Price: 60p

By N.W. & J.P. Tuck

Editor:D.J. Irwin, The Belfry, Wells Road, Priddy, Nr. Wells, Somerset.

Further copies are available from B. M. Ellis, Knockauns, Combwich, Bridgwater, Somerset.



Some Roman sites shown as follows:-

      Legionary fortress

¦ Fort

•   Town

o  Settlement



Page 20, 2nd para, line 10 should read:-

found on Page 32).    The comb was        …………..


We wish to express our appreciation of the help given by many-people, who willingly gave information and  encouragement.

We are particularly indebted to: –

Dr. H. N. Savory, M.A., F.S.A., and Mr. G. C. Boon, B.A., F.S.A., F.R.N.S., of the National Museum of Wales, Cardiff.

Mr. A. Griddle, B.Sc, Iff.Sc., who has made a detailed study of the mineralisation of this area.

Professor J. Piatt, and other staff of the University College of Wales, Department of Mineral Exploitation.

Members of the Forestry Commission, in particular Mr. Geoffrey Rose, and many caving friends.

We also wish to thank the Forestry Commission and Residual Lands Limited who allowed us to carry out this exploration.


Permission to explore the workings within the forest must be sought from the Forestry Commission, whose local office is situated just south of the Maen Llwyd Inn, Rudry.

Permission should be obtained also from the holders of the Mineral Rights who are: –


Part of the area is leased to Glamorgan Naturalist Trust.


Roman Mine was first entered, in March 1965 by a party of four cavers including the authors.  (1)

The discovery was made quite by chance – we were Looking for Draethen Mine which we knew lay in one of the depressions.  While searching for the entrance to Draethei Mine we came across this depression which had a small hole in the bottom.  Stones dropped in fell an estimated distance of fifty feet, there was a strong draught, and the expedition to Draethen Mine was abandoned in the search of the unknown.

Much digging widened the small hole from about a foot across to a size big enough to let us through.  An incredible length of ladder was fed in (and unknown to us piled up on the slope inside! and we slid in down a long earthy slope.  Our excitement grew as we began to follow the passage, for beautiful stalactite and stalagmite was everywhere and we were sure that we were the first to see the mine probably since it was abandoned.  Charcoal lay everywhere, some with stalagmite formed over it; we became more convinced that we were in a mine of respectable age.  As we explored more passages, we came to the conclusion at the time that we were in a natural cave which had been much worked over and enlarged by the miners.  The walls were smooth and the stalactite so profuse that it was difficult, to believe otherwise, but this conclusion has since been proved erroneous.  In fact the delay in producing this report has been due so the ability of Roman Mine to produce constant surprises, and new evidence contradicting what seemed to be so certain a short time before.

It was not until about four hours later that we made our first important discovery within the mine.  At the end of one passage blocked by a pile of miners infill, lay a piece of pottery, and while searching among the rocks for more shards, we found pieces of comb carved out of bone.  The pottery was later identified as Roman, and we then knew that we had found something quite out of the ordinary.


The hill of Coed Gefn Pwll du lies on the south-eastern rim of the South Wales “basin and consists chiefly of Carboniferous Limestone.  The strata generally dips to the north-west, usually at an angle of between 20° and 35°, but this is variable.  The hill is associated with the Caerphilly Syncline .

Draethen Brook has cut its course mainly along the Old Red Sandstone, near its junction with the Lower Limestone shales, and above these shales lies the Carboniferous Limestone series.  At the north-western side of Coed Cefn Pwll du this limestone dips under the Millstone Grit, three coal seams (which have been mined) and eventually the Pennant Sandstone.  Coal can be seen outcropping along the forestry road which runs south from the forestry gate near Rhyd-y-gwern.  However, the whole area of the hill under which the mines Lie consists of Carboniferous Limestone which has been dolomitised, the succession being as follows: –

6.         Coal Measures

5.         Millstone Grit

4.         Dolomite (recrystallised with pseudobreccia)

3.         Lower Limestone Mudstone

2.         Lower Limestone Shales

1.         Old Red Sandstone

Within the dolomite mineralisation took place along the joint patterns which subsequently acted as loci of tectonic movement, faulting affecting most but not all of the complex vein systems.  Many of the mines were worked in the more intensely faulted and brecciated veins.  A. J. Griddle considers however that some of the ore bodies represent cavity or cave infilling, and the origin of the two kinds of mineralisation is still debatable.  (2)

Minerals  occurring (in order of decreasing quantity approximately) are : –

Barytes, calcite, galena; dolomite, Limonite, quartz; sulphides of copper – bornite, digenite, chalcopyrite; carbonates of lead, copper and zinc – cerrussite, anglesite, malachite, Smithsonite.  Sphalerite has recently been found in the cavity infill deposits near Rhyd-y-gwern and in the mining debris on the tram track leading down to Cwm Leyshon.



Whilst this report deals chiefly with the Roman Mine-Draethen Mine line of workings, a note will be made first of the various groups of mines in the vicinity.  These are :-

A.        Ochr-chwith.  

Extensive areas of large depressions, now grassed over, between Machen and Ochr-chwith, in dolomite as at Coed Cefn- pwll-du, and with similar minerals to be found in the vicinity.  Although there is faulting nearby, the mines are not on a fault line and the veins of barytes with galena appear to pre-date this faulting.

A possible reference is in the Tredegar MS. (3)  This is an article of agreement made in about 1665 for mining to take place “in the parish of Mauchon in the Co. of Monmouth.  .  . for one and twenty years”.  The workings are well described in the Powis MS (4) which is tentatively dated to the last quarter of the 18th century.  (The extract is quoted in this Report, Ch. 7) William Coxe in his book of 1801 mentions ‘mines of lead, calamine and coal’ on Machen Hill, just west of Risca, which probably refers to at least some of these (5).

Whether mining was carried out in much earlier times is not know but the workings might be interesting to investigate because they are above and only one mile away from Lower Machen. Roman settlement.

B.        Shaft at Rhyd-y-gwern.  (6)    

A twenty-foot deep shaft leads to workings running in a north-south direction.   About 150 feet of passage is known at present but further progress is often barred by very deep water.  The level of this fluctuates greatly and is probably dependant on the water table since a spring rises nearby at about this level.  Beyond the pool the passage has been blocked with rubble, presumably from the surface.

The ore is very profuse indeed even in the entrance shaft and consists of galena, quartz, barytes, sphalerite, with minute quantities of arsenic etc.  This is one of the few places in the South Wales outcrop where quartz is found in association with galena. The ore may have originated in a cave infilling.  There appear to have been natural fissures here before the mining.

From the richness of the deposits remaining, it is thought that the mine was commenced and then deserted at an early stage.  Shot holes can be seen in the walls, indicating that these workings are comparatively modern.  They may be trial workings following the license given in 1871.  Map reference: 214 884.

C.        Line of depressions on side of hill overlooking Draethen Brook (East end).

Shallow depressions, not yet investigated.   No shafts known.  Map reference:    214 875.

D.        Depressions just north-east of Maen-llwyd Inn. 

Small pits giving access to small workings about ten feet under surface.  Passages variable in size, up to 7 feet in height.  Little stalactite, but barytes, galena and calcite can be seen in them.  Their age is unknown but they were probably grubbed out sometime before the 19th century working, their haphazard nature suggests that they are neither Roman nor 19th century.  They might have been mined in the 18th century (8).

The shaft marked on the 6″ Ordnance Survey map is now only eight feet deep (blocked).  One working leading off is about 7 feet long, 3 feet high and 3£ feet wide.  There is a vein 6″ wide in the roof, and other veins and pockets of barytes and galena. Sootmarks cover the walls »   Map references 204 868.

E.        Workings south of Penhow in Coed Llwyn-hir.

Very large square cut shaft, probably a trial, now filled in but revealed by settlement of infill.    Shaft vertical.

Much ore has obviously been taken from these mines and there are large dumps of spoil; rakes and cuttings can also be seen in the vicinity.  A tram track led from here to Cwm Leyshon, and these shafts are clearly remainders of the last period of mining. Map reference:   208 870.

F.         Long rake near Penhow entrance to Forest. 

Age uncertain but the shothole in the underground working at the end, and the rake’s proximity to the 19th century excavations and the tram track, suggests that it belongs to the more modern period of working  (See E).  Map reference: 207 870.

G.        Cwm Leyshon.  

An adit leading north-west and draining water connects with a vertical shaft leading from the surface and about 130 feet deep to water level.   Another vertical shaft also connects with the adit, calcite gangue 5-6 feet across can be seen.  The adit can be followed across the water in the shaft and continues north-west but cannot be followed further owing to the exceedingly dangerous conditions of the roof.  When the water level is low, lower galleries can be seen leading off below the adit, and probably others exist, but the level of the water precludes exploration.  Great care should be taken by anyone risking entering this adit – both the floor and the roof are on the point of collapse at points not far from the entrance.

These mines must also belong to the last period of mining on the hill at about 1850.  Map references:  211 872 & 211 871.

H.        Cwm Leyshon.   

Series of small depressions in a line from the above shafts in a westerly direction? and up hillside to the north­east .     No information, may belong to same period as (G).  Map reference: 212 871.

I.           Adit in quarry near valley bottom near Draethen village. 

Nothing known, probably not Roman or modern.

J.          Mine workings south-east of Maen Llwyd Inn.   

These are for haematite and show that the galena zone dies cut here, giving way to the iron deposits which occur from this vicinity to Llanharry, Glam.

These Rudry haematite mines were worked from 1868 to 1876. T he ore follows the base of the main limestone which here dips to the north (12). Map reference:   204 865.

K.         Depressions each side of Forestry road, just south of Draethen Mine. 

Large but blocked.  Before the road was built, a gallery could be followed for about 100 feet in an approximately westerly direction, but this was destroyed during road making.  It was entered at the bottom of a depression, was constricted at first, but continued as a rift about fifteen feet high and over six feet wide. Map reference:    214 875.

L.         Circular pits just to the west of the Forestry gate past entrance to Penhow. 

Now filled.  There are a few deads around, pieces of barytes can be seen. Map reference:   207 871.

M.       Draethen Mine – Roman Mine line. 

The hillside is scarred with pits and dumps from mining activity, but the most obvious pits lie in the line between these two mines, marking the direction of a main run of ore and the subsequent faulting.  The group consists of both shallow and deep depressions, sometimes with rock sides, and sloping shafts giving access occasionally to underground workings. (Not Draethen shaft which is vertical.)  They are situated about half a mile from the Roman settlement at Lower Machen.

The hanging (south; wall frequently shows slickensides in both Roman and Draethen Mines, and the shape of the passages is very dependant on this fault which appears to have had some vertical movement.  The passages of the Second Rift in Roman Mine also exhibit signs of faulting by more slickensides in certain places – for example in Hoot Passage.


Vein of calcite

Oxidised galena

Against the hanging wall lies fault breccia intermixed with galena and other minerals already described.  In Roman Mine at Mouse Corner there are signs that brecciation followed the deposition of galena.

Draethen Mine might have originated as a tectonic chamber.  Signs of the working of about 1850 can be seen three-quarters of the way along the western galleries, but most of the working appears to be earlier.  The eastern workings are quite different in character from the rest of the mine.

It is difficult to assess the richness or size of the veins of galena before they were worked, as the remnants are usually poor, especially in Woman Mine.  In Draethen Mine small deposits of rich ore can be seen in the lower rifts under the modern workings.

However, most of the galleries in both mines have been so worked out that it is hard to find anything but minute veins and pockets left.

Ores taken later from Coed Cefn-Pwll-Du and Machen Hill have been examined by A.J.Griddle who has found that their silver content is reasonably high, between three and six ounces of silver to the ton.  This proportion of silver is much greater than in any other lead ores found in South Wales.

Map reference of Roman Mine:   217 877

Map reference of Little Mine: 216 877

Map reference of Draethen Mine: 214 876


The pre-Roman inhabitants of Britain mined Lead, and it is not impossible that the Silures knew of its existence at Cefn Coed Pwll du, or even that they mined some of it.  The Romans first came into contact with the Silures in AD 47, but guerrilla warfare continued until AD 75 (13) when Julius Prontinus gained the stronger hand.  Caerleon was founded in AD 74 – 75, a Roman fort (14) was estab­lished just north-west of the present Caerphilly Castle in AD 75 (inhabited until about the middle of the 2nd century) and the Machen area was in Roman hands by AD 75, even perhaps before (15).

The invaders began mining at sites in Britain at the earliest possible opportunity, as they required large quantities of metal both for export and for use in their settlements.   Caerleon and Caerwent must have need considerable quantities of lead for roofs, piping and other purposes.  Part of a pig of lead found during excavations in House XXVIN at Caerwent in 1947 can be seen in the National Museum of Wales; the inscription reading L)EG II AVG denotes that it was the property of the legion, and the fragments of slag embedded in the under-surface show that the pig came direct from the smelting works.  It was considered that the lead of this pig could have had its source in the Draethen-Maonen area.

Lead mines were Imperial property and, in such newly-settled country as this part of Wales, lead mining may have fallen under military supervision.  The Second Augustan Legion, who had been overseers at the extensive lead mining works and smelteries on the Mendips, were transferred to Caerleon which remained their head­quarters during most of the Roman occupation.  It is possible that they supervised the lead workings at Coed Cefn Pwll du for a time(16).

In 1937, excavations for the new road at Lower Machen revealed a Roman settlement extending from the Post Office for 400 yards eastwards along the south edge of the old road (17).  Amongst the finds were layers of charcoal with numerous pieces of lead, lead ore and pottery of the late 1st century and the 2nd century.  It is thought that the site was a small mining settlement under government control from Caerleon, about eight miles away and the nearest military station.

In 1779, John Strange observed “….in some old lead mines at Keve’npwll du, near Machen, are very deep and large caverns in the limestone rock, which, as well as from their great extent, as the manner in which they appear to have been worked, are supposed by the inhabitants in the neighbourhood to have been opened by the Romans.  However that may be, Roman coins, especially of brass, are not uncommonly found there” (l8).  Again, he says that coins of Nero and Domitian have been found in workings for lead at Coed Cefn Pwll Du (19).

The precise provenance of these coins not being known,  it was assumed that Roman lead mining in this area would not be surface pits, and it was not until March 1965 that more evidence was forth­coming when Roman Mine was discovered and an investigation found under ground galleries obviously unentered for a considerable time (1).

Late in the 4th century the Romans left Wales and almost no mining took place in South Wales from then until 1066.  Viking raid­ers swept in from the coasts between the 9th and 11th century, even raiding Newport in the reign of William I.  They may have had some permanent settlements, possibly near Cardiff (13).

A little lead mining is known in Monmouthshire and Glamorgan in the 11th and early 12th century, but none is known in the vicinity of Machen.   In 1268 Gilbert De Clare started building Caerphilly Castle (21); one is tempted, to think that he may have obtained lead from the sources near Machen.  In England, more lead mining took place between 1350 and 1400, and many old workings dating before the intro­duction of gunpowder could belong to this period (22) but again there is no evidence of interest in the Machen area.  North (23) considers that mining in Wales restarted in 1485, getting into its stride about 1564.  A great period of lead mining came in the 17th century; gun­powder was in use before 1700 and was frequently used by the end of the 18th century (11).  Another change in mining technique took place at the end of the 18th century.  From Mediaeval times until the 18th century underhand was general, but after this overhead stoping was introduced (25).

An Article of Agreement drawn up in about 1665, between William Morgan of Tredagar and Robert Stanfield and William Sawer of Llantrisant, allowed the two miners to dig for lead in the parish of Machen in the county of Monmouth for twenty-one years, and provided that they could deliver the seventh part of ore as payment “…at such place as the same oar shall wased and purified” (3).  These workings would presumably have been to the east of the Thymney be­tween Machen and Ochr-ehwith.

According to the Powis Manuscript, ore was taken out by Mr. Hopkin Rees and Company about 100 years later.  These documents can­not be accurately dated, but perhaps belong to the last half of the 18th century, probably nearer 1800.  Since one described so fully the state of mining activities in the neighbourhood at that time, it is here quoted in full:-


An account of the Mines proposed to be taken of Mr. Morgan of Tredegar.

(commonly known by the name of Machan Mine in two different parishes)

The mines are situated within the County of Glamorgan and partly within the County of Monmouth.  The Veins make their courses E and W, crossing the River Romney which divides the said counties.

These mines were discover’d and work’d by the Romans more than a mile up-on the Glamorgan sides in a western direction, to a certain point where Mr. Morgan’s lands are cut off by the Earl of Plymouth’s estates, and even into these, for some range, the workings were confined;  tho’, seemingly, upon the declension:  Which, with some degree of probability, may thus be accounted for. Viz. that here the Bearing Beds dipping fast to the westward, by open-cast (the only method of mining in use with the Romans) they could scarcely be reached to in the Earl of Plymouth’s lands:  Yet visibly many ancient attempts were made, for that purpose.  From the River to this boundary, the Ground rises; and here a Flat, suddenly intervening, may naturally occasion the fast dipping of the beds.  Three or four Capital Veins (running parallel to, and at inconsiderable distances from each other) were here wrought upon within Mr. Morgan’s limits.  A deep level may be gained from the East, and be driven upon the course of the most eligible of these veins; and hence, by Cross-Cuts, discoveries (at a very small expence) may be made into every other of the parallel veins.

Upon the eastern side of the river (in Monmouthshire) all these Veins (with some others) have likewise been wrought.  Hillocks (now coated over with the common Verdure of the Mountain) are here also to be traced, in a course of Two Miles; abounding with tender Lead-Ore, and plainly indicating immense treasures formerly to have been scooped out of their adjacent Veins.

No appearance of Adit, or Shaft (Inventions of much later date than Roman Era) is, in any place, to be met with among these Old Workings.  Modern Powers were then wanting to prosecute such discoveries in depth; and adepts, of later ages, have largely availed themselves thereby.  Commodious Levels are here to be gained from the west, with equal advantages arising there from, as from that already mentioned, upon the other side of the River.

There remains no tradition of these Works in the Country; and casually (with in Twenty Years) the Eyes of its Inhabitants in some small measure, were thus open’d concerning them.  An Hillock, having been broken up for the repair of an adjoining High-Road, Lead Ore appeared therein, in such plenty, that the Pile was turned over, and cleared to good profit:   some Roman Coins were, likewise, discover’d to be in it.

A lease far the term of Seven Years was hereupon solicited for, and obtained by Mr. Hopkin Rees and Company.  An Eighth ton was given in tribute and the lesser allowed timber for the necessary uses of the Mines.  Their Tryals were made to the Eastward, wide of the range of the Veins afore mentioned: there the Adven­turers discover’ed a Belly of Ore which yielded many Hundred Tons, at an easy expence; and continued to yield ore until the expiration of their term.  The Company avoided to look: into the Old-Works, which, under so short a limitation, would have been imprudent to have attempted.

At the expiration of the Lease, the Proprietor,  judging this to be an object well meriting his own attention, took up the advenure; prosecuting the same, at large cost, only in such places where the Company had, heretofore, been engaged.  The Metal having in a greater measure, been hence exhausted; The Project, in course of time, and expence, became discouraging; and totally disregarding those Ancient Remains which point out the surest riches.  These Valuable Mines stand, to this day, entirely neglected.  Streams of water may plentifully be obtained for the uses of them.  The Neighborhood abounds with timber; and their situation not more than five computed miles distant from Water Carriage.   In short, regarding all circumstances, this affair may well be judged, in the mineral way, to be one of the most desirable objects in Great Britain.

Whilst the possibility of mediaeval as well as Roman lead-working at Coed Cefn pwll du and Machen Hill must not be over­looked, the Powis MSS clearly indicate that much of the working on these hills had already been carried out by the end of the 18th. cent.  Lewis (8) quotes a little lead-mining in Maen Llwyd in the 18th.cent.  It is odd that John Strage does not mention any contem­porary or recent workings at the time of his writing in 1779.

After 1800, following indications of earlier workings, a new generation of lead miners began work on the hill of Coed Cefn Pwll du, and evidence of their efforts has been found in part of Drae­then Mine, only 1,000 ft. west of the present entrance of Roman Mine.  The remains of a tram track, modern shafts, clay pipes, nails, broken shoes, etc., tan still be seen – but so can stalag­mite obviously existing prior to this time and turned over by these miners.  Working is thought to have taken place until 1855, since when the mines have been disused.  It is said that the ore was washed in the Draethen Brook near Gwm Glesyn (Cwra Leyshon), and it is supposed to have been smelted at a furnace at Farm Furnace Blwm at the west of Caerphilly Common (7). Lead slag has been found near the junction of Cwm Leyshon and the Maen Llwyd – Draethen road; suggesting that it belongs to the 19th. cent, working.

A license to dig trial pits for ore in Rhyd-y-gwern and Rudry was granted in 1871, but it is not known if any mining followed this.  The agent of Lord Tredegar would not allow the lead to be washed in Draethen Brrok which was used by the Draethen villagers(28).

The records of these later periods of working are so scanty as to be misleading.  It is clear that large quantities of ore have bean removed from this hill throughout the last two thousand years, and yet the only tonnages recorded are very small.  Perhaps because of this, North thought that “the ore is rarely present in paying quantity and efforts to exploit it in modern times have been short lived.  (27)


Main Passage is cut in fault breccia, and the miners have excavated the breccia which is here interpenetrated with ore.  The southern wall is fairly straight, following a fault line, and shows frequent slickensides; it hangs over the passage at an angle of about 70°.  The northern wall is irregular, its shape depending on the distri­bution of the ore.  Supplementary veins have been taken out of pockets at high and low levels, and a ledge behind the hearth has been cut to follow a thin horizontal vein.  The roof is generally rounded, meeting the south wall at an angle.

Scraped out veins of galena can be seen; a vein ½” wide has been left although wider veins have been left in places.  There are tool marks going up vertically into the ceiling.  They were made by a pointed implement of square cross-section, the longest mark seen was ¾” deep.

The floor along Main Passage consists of rubble (in size from mud to rocks of about 18″ in diameter) to a known depth of eighteen feet in places and probably considerably more.  Mixed with this is much charcoal, often with stalagmite overlying it.  All the rubble has settled down towards and under the southern wall, following the angle of the rock walls.  The hearth has heaps of deads about 15 feet to each side of it, the one on the east may be spoil from cavities above, and the heap on the west perhaps from other cavities with the little pool.  Stalactite and stalagmite is very profuse.

This passage is at present between 18 inches and twenty feet in height and nearly three hundred feet long.    It may have extended past Mouse Corner in the west and certainly extended past the present entrance towards the eastern edge of the hill.  This end is choked with a cone of mainly earthy material down which one climbs from the entrance, but digging between the rock wall and this debris shows that the passage extends downward and eastward without change so far as we have excavated.

Including the present entrance shaft, there are five possible openings to the surface above; the distances between them are approximately 60 feet, 60 feet, 90 feet, and 40 feet, from east to west.  At Mouse Corner is an area of collapse which may disguise a connection to the surface.  Before the survey of the mine was carried out, readings were made with a radio-location device at the junction of Mouse Corner and Mouse Crawl which indicated that this point lay 98 feet under the surface.  However this was not borne out by the survey, which showed that Mouse Corner was 70 feet below the surface.  A sloping shaft from this junction could connect with the depression a few yards east of Little Mine.

The archaeological evidence found in Main Passage will be discussed later.  As the roof above the hearth is solid, the pottery and other finds at this point could not have fallen in from above.  There appears to have been little or no settlement of the deads at the hearth site since the hearth was used.




MOUSE CRAWL: – CROSS SECTIONS                                                                     Scale: 1” reps. 4ft.

Lower end (looking approx. to North)

Junction looking to Mouse Crawl


Stalactites ½” long


Rubble with charcoal floor.  Two small stal. Flows on deads.  Deads to depth unknown at this point.

Flat rock floor.

Deads and charcoal at sides.

Although this passage is small, its width and depth would be much greater if the deads were cleared out.  They appear to have run in or to have been piled in from the western side, and could indicate a gallery or shaft behind Mouse Corner.  The passage has a rock floor only 2 ft. 3″ below the roof at one end, but for the most part its depth and shape are unknown.

At the southern end of Mouse Crawl (on the west wall) a vein can be seen about ½” thick and dipping to the south-west.  It has been worked out to leave the roof sloping at the same angle as the original vein.  As the vein rises towards the direction of Mouse Corner, the roof becomes higher until the vein is either too far in or too inferior in quality to be worth following.   The roof height immediately drops to the low portion of Mouse Crawl.

The wide shape of Mouse Crawl, as it now is, perhaps caused by the flatter angle of the vein, is quite different in cross-section from the usual rift-shaped workings of the Mine.


Comb Rift has a rift-like appearance, slopes at about 60°, and extends downward for at leash thirty feel and upward indefinitely.  N. Tuck’s excavations to find the route upward have completely changed the appearance of this pact of the mine.The passage a few feet to the west of the point drawn above appears to have been cut to follow a vein of ore dipping at about 70° to the south east.  There are several chambers in the vicinity which are now almost filled with deads and thickly stalagmited.

It was found (1965) that the width from the edge of the passage to the west side was ten feet, and there was open space downward for twelve feet from this point and five feet upward.  The rubble lay at a just stable angle of about 50° and consisted of large rocks (up to 15″ diameter) mixed with small rocks, charcoal, and animal bones (domestic).  There was no stalactite.  Lying partly between and partly on top of these large rocks were portions of a Viking bone comb, none of which were more than six feet apart.  (A report by Dr. Savory of the National Museum of Wales can be
found on Page          ).  The comb was fragile and would certainly have been crushed had such rocks moved far; because of this we consider that when the comb was dropped in, the shaft must have been open almost to this depth, causing the comb to land on the deads only a few feet above Potsherd Passage level.  Since then, movement of the rubble scree has separated the segments of the comb.  A search was made as much as possible for the remainder of the comb, but the angle and size of the deads made their removal so extremely dangerous to anyone digging there that we were not able to follow the rift downwards.  As the continuing shaft below is filled loosely with deads for at least twenty feet below the level of Potsherd Passage and thus below the comb, it, must have bean filled to this point before the 11th century.

Many tons of rocks have since been brought down from the upper part of the rift, but it, has still not been possible to clear a way upward.  The large deads were followed by small rooks and earth, more animal bones, one piece of (?) 1st century pottery, and a piece of white glass bottle thought to be of modern manufacture which makes it evident that the shaft has been almost open with the surface until recent times, and probably connects with the sur­face.  The presence of the Roman shard above the comb is not difficult to account for on such a steep slope of rock debris, as any movement would have caused parts of the infill to move down­wards for differing distances.  The pottery might also have been knocked into the shaft at a much later date.

When rocks are moved in this rift, there is corresponding move­ment at another unknown place combined with loud distant rumbling, and it is therefore probable that other open galleries exist above, perhaps extensions from Mouse Corner.  Rocks moving in Comb Rift can be heard at Mouse Corner, and vice versa, so that there must be a direct connection between these two places which is not accessible at present.  There must also have been workings below connected to this shaft, for it appears to be too large to be merely a trial shaft or a hauling way for the small vein of ore along Potsherd Passage.  Possible workings underneath must at this stage remain conjectural, but points to be considered are (a) the workings if any would be expected to run in an east-west direction following the veins, and (b) there are continuous surface indic­ations of workings of unknown age from this point towards the west.  Perhaps the Romans threw deads into the lower part of this shaft and moved on to the next valuable part of the hill, or perhaps deads in an undiscovered working above collapsed into Comb Rift at post Roman, pre-Viking times.  This cannot be clarified until further excavation of the shaft is carried out.

A provisional survey showed that Comb Rift lies in the vicinity of Little Mine, and we therefore attempted to dig down into it at this point.  An excavation to a depth of about twelve feet was made at the bottom of the slope into Little Mine, and it was found that a cut shaft continues (blocked with earth and leaf humus) below this point, but that shoring would be necessary before work could be continued.  Another excavation was made in the furthest and deepest part of Little Mine.  This revealed that the rock wall continued downwards under the miners’ waste, but after only two feet it was found that the rocks were not only covered in stalag­mite but were cemented solidly together: proof that the way to Comb Rift, following a modern glass bottle, could not lie here.

Another effort to prove a connection was made in September, 1968, when a smoke flare was set off in Comb Rift.  All the depressions around Little Mine and Roman Mine were watched with only negative results.  No smoke came up the present entrance of Roman Mine either.

In January, 1969, readings with a radio-location device were made to find the exact position of Comb Rift in relation to the surface.  An instrument measuring the electro-magnetic field was set up in Comb Rift at the level of Potsherd Passage floor, and the signals received indicated that this point lies vertically underneath a small mound about 30 feet south of Little Mine, and 85 feet under the surface.

This was not borne out by the Survey later, which shows that it is in fact about 86 feet below ground level, and under a point about 50 feet east of Little Mine, i.e. nearer the next depression.  It will be necessary to excavate in Little Mine before the pattern of workings in this vicinity can be plotted with certainty.


Upper Ledge Passage was worked to follow a vein of ore.  A hole in the floor and a connection towards the western end gives access to Middle Passage.

At the eastern end this gallery becomes a ledge at the top of the Aven, from which a low passage (Gour Passage) opens into Main Passage at high level via The Windows.

The whole of Upper Ledge Passage is heavily decorated with stalactite and thick flows of stalagmite over the floor.  There are shallow deads mixed with charcoal.

MIDDLE PASSAGE (at second hearth)                                                                                     Scale: 1” reps. 4 feet


Middle Passage was excavated to follow a very steep vein 1” wide which can be seen in the roof of the passage.  Supplementary veins have been picked out in pockets.  The veins continue up into Upper Ledge Passage and down into the deep rifts under Bloody Ledge.  There are deads on the floor mixed with charcoal; their pattern indicates that they were thrown back by miners working towards the west.  Many stalactites have formed.

A hearth of unknown date can be seen. A search was made under and around the hearth for archaeological evidence, but nothing was found.


Remains of a thin vein are visible in the Lower Traverse Passage; the direction in which it was worked is not known.  It is obviously deeper, at the western end under the deads which now nearly fill it.

Charcoal is mixed with the debris and stalagmite has formed over the floor.  There are many stalactites.  The walls are blackened, probably with smoke.

Under the Lower Traverse Passage are two short tunnels, one only a few feet long.  The other, named Lower Traverse Cul-de-Sac Passage, was excavated to follow a small horizontal vein which can be seen along the roof (now ½” wide).  Both must have been worked from east to west, have shallow deads and much charcoal stalagmited in over the floor, and are very pretty with profuse stalactites and thin curtains of flowstone.  Fine examples of the types of stalactites peculiar to this hill are found here (a description of these will be found elsewhere).



Cut to follow the deep portion of the main vein of ore which slopes down from Upper Ledge Passage.  They were worked downward and the ore hauled up.  A vein 3″ wide can be seen in the roof of the westerly working.

The actual depth of these rift-shaped passages is not known as the base is filled with mixed rubble and charcoal.  They are free of stalagmite.  The roof and walls are covered with a soft black deposit ?” thick, probably carbon deposited from the smoke of fire-setting.


Scale: Roughly 1″ reps 8 feet


The Aven is a main shaft sloping to the south.  The width varies between 20 and 30 feet broad from east to west;  between two and six feet broad from north to south.  The total height of the Aven is just over 50 feet.

It does not cut through to the surface, which lies about 63 feet above the roof, but gives access to all the passages in the Second Rift.  Most of these now (partly blocked with deads) are constricted.  A ledge about twelve feet above the bottom has charcoal and rubble lying upon it.  At the bottom but along a few feet to the west, is a pool about five feet deep.

Below this same ledge is a small working, rift-shaped, leading down to the west.  A portion of clay pipe stem was found in this, lying on the deads a yard from the Aven.  No further pieces could be found, but it is possible that the pipe fell down the Aven and that the remainder could be in or near the pool.

Because of the irregular shape of the Aven, it is thought that it was probably excavated to follow a larger deposit of ore, although it may have doubled as a raise.


This is a narrow but lofty rift, the main connection between Main Passage and the Second Rift Passages.  High in the southern wall at the lower end is another working heading towards the east at about the level of the lower chockstones across the Aven.

Many deads fill the lower part, there is also charcoal.  Stalac­tite and stalagmite is present, particularly at the Main Passage end.

This gallery presents a problem.  From its position it should have been a throughway for the ore to be brought out, but at the levels now accessible its width is fairly constricted and no effort has been made to widen the passage for easy portage of ore.   Perhaps it is larger under the present layer of rubble, but this is doubtful.


Dangerous Passage has been mined to follow the lower part of a vertical vein below Pool Passage and below Main Passage with which it appears to have connected.  Deads of variable depth fill the nar­row part at the bottom of the rift.    There is charcoal but little stalactite.

Although parts of the roof of this passage are of bedrock, others are of loose deads which have been thrown in from the gallery above.  The ceiling in one place is so unstable that it will not be possible to pass under it without a strong roof support, and because of this we have not been able to follow to the end although the passage can be seen continuing in a straight line to the east.

The survey indicates that it ran through to the bottom of the entrance rift but was probably not used as a throughway for ore from the Second Rift passages as it was awkward and constricted.

It must pre-date the eastern end of Main Passage, or the deads in the roof could not have been piled in from above.


ROOT PASSAGE                                                                                                   Scale: 1″ reps. 4 ft.

-The Entrance.

Looking north into Aven.


                                     stal floor

East of Aven: Cut to follow a narrow vein in the middle section from the Aven to beyond the long pool.  The vein has been picked out as far as is practicable.  Beyond the pool, the vein lies parallel with the southern sloping wall which may be another fault plane.  The miners have taken the vein out to a total depth of perhaps twenty feet, leaving a tall narrow rift-shaped passage, but as the lower parts are filled with deads, the lower limit is not known.  This peters out 130 feet east of the window into the Aven.  The rift-gallery at this end is usually only two feet or so wide.

There are deads of variable depth, and charcoal.  There is profuse and very pretty stalactite, some of the longest in the mine, and appearing quite undisturbed.  Stalagmite lies over much of the rubble.  This passage rises towards the surface but does not connect with it.  Decayed hair roots from the trees above can be seen hanging from the roof in places.

West of Aven: The passage branches into about three small parts where ore has been worked out, generally lower than the windows. Stalactite is profuse.

The only outlets for both these workings are the two windows into the top of the Aven, and all the ore must have been brought out this way.



The discovery of the comb and shead during the first exploration, of Roman Mine led to the finding of a hearth in the Main.  Passage, remains of a fire place in the Middle Passage, and other smaller objects in various parts of the mine.  All the small finds are in the care of the National Museum of Wales (Reference 66.518), on loan from the trustees of the Tredegar Estate.


It was not possible to carry out a formal archaeological excavation because of the cramped conditions in most of the mine, and because of the enormous volume of miners’ deads often piled up at steep angles.  Artefacts found could not be attributed to any particular stratigraphical position as any object dropped on the floor in the past would be likely to fall two or three feet through the debris.  For these reasons we decided to limit excavation to the careful examination of the floor of each passage and not dig to any depth except in certain places as here described.


A mound of rocks in one of the wider parts of Main Passage attracted attention when large basal shards were seen lying on the surface beside and under the skeleton of an animal, and a circle of rocks filled with charcoal was revealed about two feet to the east.  A site 15 feet long and about 5 feet wide was taped off, and excavated to a depth of three feet by the hearth and two feet at the western end.  The hearth itself was not disturbed.



Large grey basal shards

Grey shards similar to (4)

Light grey, portion of rim

Black with undulating pattern.

Rough dark grey,  large wavy patterned


Lying with fox remains on top of deads

Just under surface and at deeper levels

Depth 15″

Depth 12″

Depth 10″

Ref No


6, 24, 30





Copy of Antoninianius Tetricus II AD 270-274 (12mm diameter)

Copy of coin similar to (5) AD 274-282

Many small bronze pieces

Bronze coins, indecipherable

Bronze blanks         


Just under the surface

Just under the surface

Scattered over many feet

Depth about 10″

Depth between 9″ – 12″




14, 23, 28

19, 20

22A, B, C, D


Bone and hair of fox

Iron nail

Two pieces of iron

1″ long stalactite straw

Piece of bronze length 7/16″

Two cave pearls

Many tiny cave pearls

Soft material

Much charcoal throughout



Inside hearth ring in charcoal and ash

Depth about 6″

On rock upturned amongst deads

Depth 13″.  This appears to be the remainder of a bar from which coin blanks were cut

Depth about 13″.  These stalagtitic formations were found out of natural context.  They must have been dropped there by human agency, not formed there in the deads.

Depth about 12″.  Mixed with charcoal.  Out of context.  Appeared as if a small shovelful had been dumped in deads.

Probably the remains of wood

Not in significant pattern




16, 17





18, 35



Somwe digging was done to investigate workings below the entrance door, at the bottom of the Entrance Rift and beyond Mouse Corner. But nothing of archaeological significance was found at these three places.


Dark grey course shard

Dark grey course shard


Under south wall, about seven feet east of hearth.  Fitted into pot with (4), (6) etc.

At junction with Pool Passage.  Stalagmited with deads and galena.  Possibly same vessel as (4) etc.

Ref No




Iron nail ¾” long

Mixed bones, probably domestic animals

Wood bough


Near junction with Pool Passage under a stone

Near junction with Pool Passage

Found on first visit leaning against wall near Gour Passage window.  Roughly trimmed and rotten






A fire place was discovered and this area well searched with no result. See scetch facing page.




In Potsherd Passage, one foot away from edge of Comb  Rift,  lying on smooth mud floor a shard of carinated bowl was found.  Described by the National Museum of Wales as “hard, coarse, grey ware; outer surface smoothed with a tool.  Groove just above the carination.  This type of bowl, usually in a much finer grey ware and often black-surfaced, is common in Flavian contexts at Caerleon (cf. Archaeol. Cambrens. 1929, 229, fig.36, No.120 (Jenkins Field); 1932, fig.63, Nos. Uk5 – 6 (Prysg Field); and the present specimen is probably a local copy of this type”.   At first this shard was dated c..A.D. 75 – 110, but it could be as late as 3rd. Century.

Shard in dark grey ware Wood bough


Pieces of bone comb.

Above comb in Comb Rift


In Comb Rift, mainly on level of Potsherd Passage.  Pieces within about 6ft of each other and in loose deads to a depth of about 12″




The National Museum’s report on this find is as follows: “Portion of a single-edged bone comb of the normal composite form consisting of six sawn plates held, by bone pegs, between two, slightly arched, lateral strips; a decoration of four scored lines at the end of each strip, as preserved.  The end plate is of a slightly horned shape.  This type of comb is not Romano-British, and in so far as it can be dated, clearly belongs to the Merovingian or later periods on the continent, i.e.  to the VIIth cent,  or later.  Cf. Anna Roes, Bone and Antler Objects form the Frisian Terp-Mounds (Haarlem, 1963) PI.XIX,5.  The Draethen example is plainer than this, but it exhibits the beginning of the more correctly designated ‘winged’ where the end plates protrude above the line of the back.  In the winged type, however, the back tends to be more boldly arched than here.  Dr. H. N. Savory informs me that combs of similar type have recently been found, in Viking period contexts, during excavations in the city of Dublin.  In the full medieval period, the tendency was for combs to become once more double-edged (cf. London Museum Catalogues, No.7 Medieval Catalogue (1940),291).  Although, therefore, the Draethen comb cannot be said to be closely dated, it would appear most likely to have been of “Dark Age” to early medieval date, with the emphasis probably on the 9th-llth centuries”.

Base of bottle in white glass

Bones of domestic animals

Above comb, loose in deads.  Of modern manufacture, probably 20th Century

Throughout deads




Fragment of clay pipe stem 

About 4 feet from junction with Aven. Lying on top of deads.


This little working was searched to a depth of about twelve inches but nothing more was discovered.



The pieces of pottery found throughout Roman Mine are the remains of probably six pots, including one large grey urn of height one foot (no pieces of the rim have been found), one carinated bowl, and two cooking jars.  All are probably late 3rd century in date, although one shard might belong to an earlier period.

The evidence of the coins and the remains of about one dozen counterfeiters blanks shows that forgers were using the deserted mine probably between A.D.  275 and A.D. 282.  The hearth itself cannot be identified positively as belonging to any particular century, but as it hardly been disturbed by later natural move­ment, it can probably he associated with the counterfeiting activities, for sufficient time must have elapsed for the deads to have settled since working ceased in the Main Passage.  The site is the widest convenient place for resting in, especially if the then easiest entrance was in the east.

There is thus no evidence of the exact date of the Roman mining, except that it had ceased in the Main Passage a consider­able time before the arrival of the counterfeiters.

Amongst the deads of the hearth site and under some of the shards was found the equivalent of a small bagful of tiny cave pearls, mixed with charcoal.  Two larger cave pearls were found above them, about 13″ below the top of the deads.  They could not have formed in this position, and prove that either natural fissures existed nearby which were dug away by the miners, or that there were at least two periods of working with sufficient time elapsing between them for the growth of this stalagmitic formation elsewhere.  In confirmation, amongst the deads between the hearth and the hanging wall, was found a rock with a stalactite “straw”, lying on its side.  Like the pearls, this must have been thrown there, and must have been derived either from a pre-existing natural cavity or from previous workings.  In a very few places pick marks can be seen in stalactite, but this cou1d have been done by casual explorers within the last few hundred years.  (Little significance should be given to the presence or size of stalactites in the different galleries of Roman Mine, and because a passage is bare of decoration, it should not therefore be presumed that it is more recent.  For example, many of the galleries in Draethen Mine have no stalactites, but t he re is quite a thick flowstone over the  new workings) .

The discovery of the Viking Comb is of considerable interest and value , not only in itself, but because it proves that the shaft of Comb Rift is very old and must have been open partly, probably to the surface, before the eleventh century.  The close distribution of the pieces within a few feet indicates that Comb Rift could not have been used by later miners as a route to take ore out.  The shaft extends downwards at least twenty feet, perhaps to other galleries, and must have been filled to just above the level of Potsherd Passage in pre-Viking times.  In addition, the presence of 20th century glass proves that the shaft remained partly open until recent times; it is not clear how this could have passed down the shaft past the many deads, or whether miners’ debris of a later date has been dumped into the shaft.


Just over half a mile to the east at Lower Machen lie the remains of a Roman mining settlement where many traces of lead smelting have been found.  It is thought to have been inhabited from about 75 A.D. to the  last years of the second century.  If lead was needed by these smelteries for about a hundred years, it is likely that mines other than. Roman Mine were opened at Oced Cefn Pwll du, unless a richer source was found elsewhere at an unknown site, for example, on Machen Hill.  However the close proximity of the settlement, to the workings indicates that Roman Mine itself was probably excavated during the time of the settle­ment, possibly during its earlier years since the mine seems to have been worked out.  The survey shows that Comb Rift might be the  lower part of Little Mine, and if this proves to be so, it would seem that  lead-workings took place in Little Mine in Roman times also.

The recorded coins of Hero and Domitian found in “some old lead mines” (or “in an old lead mine”) at Coed Cefn Fwll du (20) have too vague a source to be used as evidence for any particular mine or depression, but again suggest an early date for mining on the hill.  No access has yet been gained to the workings under the length between the western end of Roman Mine and the eastern end of Draethen Mine, but there is every reason to suppose that underground galleries at present blocked by roof collapse link these two mines.

The deads now filling several of the shafts in the Main Passage may have been dumped there by Roman workers, but some access way was available in the third century when the mine was used by counterfeiters.

The possibility of mediaeval or later working on the hill must not be ignored, but nothing definite relating to Coed Cefn Pwll du is known until the report by John Strange of “very deep and large caverns” showing that in 1779 there must have been access to more than one mine on the hill, and indicating that there must have been fairly substantial remains in the eighteenth century, either of shafts or of opencast mining.  The Powis Manuscripts state specifically that Mr. Hopkin Rees, and, later, the “Proprietor” did not mine the “Old Works” but made their excavations elsewhere.

The 19th century mining activities seem to have taken place to the south and west of Coed Cefn Pwll du, the workers taking ore out of Lraethen Mine and ignoring Roman Mine.

Finally, the evidence of the pipe-stem and the branch shows that, at some period between Elizabethan times and 1900, Roman Mine must have been explored.  (Wood in a similar condition is found in Draethen Mine in conjunction with artefacts of about 1850).   It is not possible to say whether Roman Mine has been open for long periods, but the unbroken stalactites and undisturbed hearth is almost in the middle of the Main Passage surest that few people have visited it since it was deserted.



Before describing mining techniques used in the Mine, it will he necessary to discuss whether all the galleries are of Roman age.

The pre-Roman inhabitants of Britain mined lead and the Romans are known to have taken over their mines immediately the relative part of the country was in their hands.  It is therefore not impossible that the existence of lead in the Machen area was known to the Silures, for the Machen mining settlement was established very early (15).  The shape of the mine is not unlike pre-Roman workings found in Montgomeryshire (10) but no evidence at all of British working has been found in the mine.

If we list the possible ways that ore could have been taken out of the Mine during its history, we find that these consist of five openings upward from Main Passage to the surface, horizontal passages to the side of the hill from the large rift under the present entrance, and Comb Rift.

The presence of the pottery and coins at the hearth site proves that Main Passage, the largest part of the mine, is 3rd century at latest, and since the archaeological remains are undisturbed it seems in the highest degree unlikely that ore could since have been brought along to the outlets between Pool Passage junction and Mouse Corner.  Comb Rift must have been more or less blocked from Dark Age times, as has already been discussed, so ore could not have been hauled up this shaft after the comb was dropped there.

If any ore was worked after the departure of the Romans, there­fore, it could only have been worked in the multiple passages of the southern rift, but the only possible means of carrying ore out in later times from these were (a) up Pool Passage and out via the eastern end of Main Passage, or (b) along to Mouse Crawl and up through the outlet behind Mouse Corner.  Either of these seems unlikely and should have caused some disturbance of the Hearth.  The two pieces of pottery found near the junction of Pool Passage and Main Passage could have been picked up and dropped by post-Roman visitors, so no conclusions will be drawn from their presence here.

This later lack of a route to carry ore out, and the similarity of working in all the galleries, allowing for differences in the quantity and the lie of the ore, disposes us to think that if the Mine was worked at all in post-Roman times, it could have been only in the smallest way.  Whilst there is no archaeological evi­dence from the Seeond Rift passages to show this, the fact that no mediaeval or other important remains have been found might be an indication, for the piece of clay pipe can be easily accounted for.

In contrast to the adjacent Draethen Mine, there is the negative evidence of no shotholes, no recent timbering, no clearly-cut vertical shafts, and no track or easy walkways, which rules out any but the slightest of mining in the nineteenth century.

A hypothetical order of working could have been as follows:

The earliest mining probably took place along the fault line outcropping down the hill, where levels were cut towards the west along a promising vein of galena.  Surface working along the top of the hill may have started from this time to find the lie of the veins or to remove valuable ore.

The main run of the ore would have led the miners along deep under what is now the Entrance Rift and into Dangerous Passage, and as the galena was excavated upward, it would have been convenient to pass it out to the side of the hill through a higher gallery.  There are clear signs of levels (a) about 30 feet below the entrance and (b) about 70 feet below the entrance.  There may be at least a third level.  Deads can be seen most of the way down the hillside.

The miners did not cut formally shaped galleries, but followed the shape of the ore bodies, throwing the waste material into the worked out spaces at the bottom or where convenient.  The passage walls therefore slope at the same angle as the veins.  Deads were thrown into the lower part of the workings, now the roof of Dangerous Passage, and work proceeded at a higher level of Main Passage.

Work in the Main Passage probably proceeded in advance of that in the Second Rift, for the greatest volume of ore-bearing rock lay along the Entrance Rift-Mouse Corner line, and should not have been difficult to follow 9 lying up against the slicken-sided wall of country rock.  Also, the ore from the Second Rift must have been passed out through Pool Passage into the existing lofty part of Main Passage, and later through Gour Passage or through to Mouse Corner.  It would have been easier to ventilate the galleries of the Second Rift if Main Passage with its surface exits was already there, and, if these exits did not exist, it would have been very useful to have extended the Aven through to the open air, an extension which was not made.

During the history of the Mine the Romans seem to have gradually worked upwards and westwards through these two main lines of galena-bearing minerals.  They used a form of overhead stoping, and beam-holes can be seen particularly in the Entrance Rift.  Perhaps they attacked this steeply inclined ore material as high as could be reached, standing on deads or wedged stemples and platforms across.  To reach the loftiest part of the present galleries along Main Passage, the miners must have had to use timbering.  No definite beamholes have been found here but there are possible niches for stemples between the Windows and Mouse Corner.  At intervals, the Romans have followed the hanging fault wall upwards as a shaft to the surface, perhaps because there was ore at these points or simply for light or as ventilation shafts and hauling ways.  Marks on the footwall of the Entrance Rift show that it was filled with deads to a height roughly the same as the deads along Main Passage and settlement probably accounts for the slumping.

The ledges and the chockstones in the Aven also suggest that it was cut from below towards the top, since access was needed across it to reach the higher workings.

Finally, the roof of Mouse Crawl seems to have been cut from the Junction towards Main Passage, partially following a small vein rising at a shallow angle.   Potsherd Passage seems to have been worked from east to west.


The Romans were competent miners, and skilled at the cupellation of silver from lead where profitable under the standards of the time.  Generally their method of mining was to open pits for ore to a depth of about fifty feet, but after this depth to drive shafts and tunnels, as the removal of such an overburden would be too laborious.  They worked in an orderly fashion, sinking shafts at frequent intervals both for removing ore and for ventilation, and supported the roof when necessary with wooden beams (29).  At Ogofau gold mine (26) timber was found which appeared to be beams for support, cross-pieces for resting upon them, and boards and branches for stopping stones from falling upon the workmen.  The entrances to mines were usually steep.

In Roman Mine charcoal is frequent throughout even in the smallest tunnels, mixed with deads, lying on ledges, and often coated with stalagmite.  Much of this charcoal is derived from the practice of fire-setting which was a method of cracking rock in use up to the early nineteenth century, even after the intro­duction of gunpowder.  Wooden fires were laid against the rock until this was heated sufficiently, and then cold water or vinegar was thrown upon it, causing it to split into angular pieces.

The fire-setting produced much smoke: a black patina can be seen over many of the walls and roofs, often incorporated in the stalactitic flows, and the deposit is ?” thick in the deep rifts under Bloody Ledge.  Partly because of this need for a good through draught, the Romans sank shafts at frequent intervals.  Whilst the Main Passage is well supplied with outlets to the surface, the passages of the Second Rift must have been difficult to clear of smoke while they were being worked.

When the gallery could be entered again after fire-setting, the miners broke the ore by hand and sorted it in the mine itself, packing the waste into deserted pockets and chambers.  The brecchia of the Main Passage is relatively easy to hack away, and working in the mine may have been facilitated by small natural cracks or fissures, some of which can be seen still.  The walls’ appearance now is remarkably smooth, the main tool marks being along the remains of the veins which have been picked out.

Tools known to the Romans are similar to many used by miners up to the present day; gads, chisels, hammers, crowbars, and single-bladed picks (30).  Iron tools were used, so also were stone wedges and hammers.  Stone tools are known to have been used up to Antonine times (31).  No tools have been found in Roman Mine, but pick marks are frequent.  They were made by a pointed tool of square cross-section, the deepest mark seen being ¾” deep.

No identifiable pieces of timber have been found and this is not surprising, for wood in the adjacent Lraethen Mine is totally decayed after only about a hundred years.  Beamholes can be seen in the Entrance Rift wall, most about 4″ across and at distances apart varying from 20 inches to 40 inches.


Davies (32) thought that in Britain miners were usually free but employed under compulsion.  Nash Williams (17) considered it likely that the labourers employed from Lower Machen were slaves and convicts under military supervision, and that they would have been accommodated in barracks grouped together.  Although mining workers often lived in deserted parts of mines, we have found no recognisable traces of this in Roman Mine.  Bones of domestic animals were found in Main Passage/Pool Passage junction, Mouse Corner, and Comb Rift, all places where they probably came from the surface, dumped in with rubble.  Although the Romans took some care of their workers, the lives of miners at this time were usually short (33).

They worked in Roman Mine in what were often very constricted places even inches wide when the vein was being followed out. Some of this labouring could be attributed to the employment of children.


The rocks obtained by picking or by fire-setting were separated into deads and ore-bearing pieces in the mine, and the rubble was packed into worked-out galleries and chambers.  The ore could have been dragged on wooden trays or wheel-less trolleys, or carried in leather sacks or wooden buckets (34).  A bucket and windlass was probably used to haul it out of the shafts as this was the usual Roman method.  Beamholes can be seen in Little Mine but until this is excavated, their age will be uncertain.

Tips of waste on the surface lie spread around the depressions along the fault line, and there is a large deposit of rubble down the hill east of the entrance (NGR.218 876).  From this we de­duce that the once-sorted ore material was hauled to the surface, and sorted over again near the shaft mouths.

It does not seem to have been washed on the hilltop.  Although the Romans were accustomed where necessary, to channel water to convenient places for washing ore (for example, at Ogofau gold mine they constructed an aqueduct seven miles long) it would have been arduous to bring water to the top of this dry hill when two large streams ran close below.  The washed ore was then taken to the smelting hearths near Lower Machen.

Although the Romans could not extract such high proportions of ore as can be done by more recent processes, they had an abundant supply of cheap labour and little machinery, so that they were able to work ores which could not be profitable in succeeding centuries.  They usually followed the vein, but if they lost it, were seldom able to find it again. (35)

The surface of the hill has been so disturbed by mining activities of different periods, road making and tree planting, that it is difficult to know where surface buildings if any may have stood.  Perhaps traces will be uncovered by the Forestry Commission in the course of its work which will tell a little more about the methods of the miners.



Some of the for mat ions in the workings at Coed Gefn pwlL du are of a most unusual type, and as far as is known have not been found elsewhere in Britain in such a well-developed form.

The stalactites and stalagmites throughout these mines are of hard crystalline material and are not the soft growths more usually associated with artificial excavations.  The archaeological evi­dence dates them as being formed during the last nineteen hundred years.  Some, usually the largest, are of pure white crystal, but many have incorporated the brown or red colouring from the iron present in the rock.  Occasionally the stalactites have horizontal stripes of colour, but in some places in Roman Mine the stalactites are lined with brown or red material inside the ordinary creamy exterior.  “Snow” formation is found on stalactites and on some of the flowstone.  A similar soft deposit is found inside some of the stalactites giving their interior a white, limey, appearance.

It is the shape of the stalactites, however, which is so notable.  It will be seen from the sketches that many of the stal­actites begin like the usual straw formations, but soon change their shape.  The bottom of the new stalactite instead of being circular develops a split at the side as it grows, often associated with a thickening of the lower part of the stal.  This may widen very rapidly into a bell or boot shape, nearly always slit at the side.  The effect is apparently caused by the water drop hanging to one side, thus depositing mineral around most, not all, of the rim.  As the stalactite grows in length or thickness, the water drop may change position and build up a deposit at an angle to the previous growth.  An irregular line is often seen down the stalactite, representing the former slit of the opening which has since been closed as the stalactite grows.

Other types of this stalactitic formation begin immediately from the roof, as in diagrams 5 and 6, with an exceptionally large water drop.  In Draethen Mine some of this shape had a large crystal floating on the surface of the water, in one case the crystal was firmly attached to the rim of the stalactite.

All types have the bell end filled with water which has passed down through the neck via the usual small space.  The edges of the bell are often very thin and fragile, but some, in contrast, have edges which are thick and smooth.  The most fully developed are of a nodular appearance, on average about 1½ inches across and 2 inches in length, when growth has been mainly outward.  The most usual length for others is 1 to 4 inches, but longer slit-sided stal have been seen, and there seems no limit to their possible size except time.  The stalactites are found at all depths, down to 150 feet below the surface.   They do not seem to be dependent on possible ventilation draughts or temperature.  Although one would expect that the slope of the roof would influence the course of the water drop in the early stages of stalactitic growth, causing the slit-side to form on the side facing the upper slope of the roof, this is not so.  Examination of groups of stalactites showed that they faced all directions.

About 80% of the formation in these mines is of this unusual shape, and it appears that whether the stalactite begins as straw, helictite or anything else, it almost always develops this tendency to bell out.  It is clear that the sloping bottom edge of the stal, and the slit-side, are caused by the drip running to one side and depositing crystals accordingly, but it is strange that this is not common also in caves in other areas(*).  Probably this out of the ordinary feature is dependent on the actual mineral content in solu­tion in the water, deriving in this area from the limestone rich in magnesium, and the nearness of these mines to the surface and plant acids.

N.W. and J. P. Tuck

* Ed. note:- Since this paper was written similar slit-sided for­mations have been seen in a cave in Cheddar Gorge, Somerset.





by D.J. Irwin.

Following the discovery of Roman Mine several important sites of archaeological interest were found within the system.  A need to accurately position these sites and to relate surface features to the mine made the requirement of an accurate survey a necessity.

The instruments used were an ex-WD liquid filled prismatic compass, clinometer and 50ft. fibron tape.  All of the instruments were calibrated and read to conform to the requirements of a Cave Research Group Survey Grade 6.  Because of the horizontal nature of the passage from Bloody Ledge to the base of the Aven the survey was carried out minus the clinometer.  Only one traverse was comp­leted to Grade 6 (Main Passage; Mouse Crawl; Bloody Ledge; Top of Aven and through window to Main Passage.)  Length 294-60ft.; Horizontal misclosure 1.29ft. and Vertical misclosure 0.17ft.; Slope error 0.44%.

Length of Roman Mine                                           Surveyed:       840.2ft.

Unsurveyed: 100.0ft. approx.

Total:- 940.0ft. approx.

Depth =  64ft.  from Ground Level (surveyed end of Dangerous Passage)

            = 46ft. below entrance gate.

The symbol         indicates the position of the hearth in Main Passage.



      1. British Caver, Vol.42 (1965) p.40 – J.Tuck
      2. M.Sc. Thesis 1967, University of Wales – Mineralisation in the Carboniferous and Mesozoic Strata in the Area of the South Crop of the South Wales Coalfield. – A. Griddle B.Sc, M.Sc.
      3. Tredegar MS 756; Pettus, p.33
      4. Powis MSS 3977 and 3978
      5. A Historical Tour Through Monmouthshire,  (Davis & Co., Hereford, 1904) – William Coxe (1st print 1801).
      6. Mem. Geol. Survey, Part (Geol. of S.W.Coalfield), 2nd Ed. 1909,  p.22
      7. Mem. Geol. Survey, Part (Geol. of S.W.Coalfield), 2nd Ed. 1909,  p.22
      8. Leadmining in Wales (University of Wales Press, 1967) p.164 – W.J.Lewis.
      9. —————       
      10. Lead mining in Wales (University of Wales Press, 1967) p.24 -W.J. Lewis
      11. Lead mining in Wales (University of Wales Press, 1967) p.l60 -W.J. Lewis
      12. Mem. Geol. Survey, Part 1  (Geol. of S.W. Coalfield) 2nd Ed. 1909 p.22
      13. The Cardiff Region – A Survey (1960). The Roman Period -L.Alcock.
      14. Archaeologia Cambrensis, Vol. CXV (1966), p.67 – J.M. Lewis
      15. Archaeologia Cambrensis, Vol. CXV (1966), p.67 – J.M. Lewis
      16. Archaeologia Cambrensis  Vol. XCIV (1939), p. 108 -V.E. Nash-Williams
      17. Archaeologia Cambrensis  Vol. XCIV (1939), p. 108 -V.E. Nash-Williams
      18. Archaeologia,   Vol.V (1779) p.377 – John Strange
      19. Archaeologia,   Vol.V (1779) p.35 – John Strange
      20. Archaeologia Cambrensis, Vol.XCI (1936) p.379 – V.E. Nash-Williams
      21. H.M.S.0 Publication – Caerphilly Castle, Glamorgan.
      22. Mining for metals in Wales (Cardiff, 1962) p. 32 – F.J. North.
      23. Mining for metals in Wales (Cardiff, 1962) p. 33 – F.J. North
      24. M 11 11 11
      25. Mining for metals in Wales (Cardiff, 1962) p. 53 – F.J. North.
      26. Mining for metals in Wales (Cardiff, 1962) p. 16 – F.J. North
      27. Mining for metals in Wales (Cardiff, 1962) p. 27 – F.J. North
      28. Journal 1871 (November 25th) p.l052
      29. Roman Mines in Europe (Clarendon Press, 1935) p.19 – O. Davis
      30. Roman Mines in Europe (Clarendon Press, 1935) p.32 – O. Davis
      31. Roman Mines in Europe (Clarendon Press, 1935) p.38 – O. Davis
      32. Roman Mines in Europe (Clarendon Press, 1935) p.14 – O. Davis
      33. Roman Mines in Europe (Clarendon Press, 1935) p.16 – O. Davis
      34. Roman Mines in Europe (Clarendon Press, 1935) p.30 – O. Davis
      35. Roman Mines in Europe (Clarendon Press, 1935) p.16 – O. Davis