Monday, 26 October 2015

A Couple of North Pennines Lead Mine Articles from Mine & Quarry Engineering

Main Menu - click above
Lead Mines of the Northern Dales

By J. E. Metcalfe, A.M.I.M.M., Assoc.M.I.M.E.
Mine & Quarry Engineering, January, 1952 

West Allendale

West Allendale was a more productive field than East Allendale, and although there was no active mining for many years (in contrast, for example, with the modern workings of Sipton), some prospecting and development were done before the war by the Vieille Montagne Zinc Company.

Kiersleywell (No. 19) was an adit which, started by the Beaumonts in 1729, worked until 1789. Attempts at revival were then carried on from 1816 to 1830 and 1847 to 1853, but only produced 597 tons of concentrates. Mohopehead (No. 4), another adit, between 1729 and 1878 produced 4,200 tons of concentrates. Wellhopehead (No. 7), at the head of the Nent Valley, another drift working, appears to be of quite ancient origin.

On the Northumberland side of the West Allen the most interesting mine is Coalcleugh (No. 14), where the earliest workings on the Low Coalcleugh Vein were from shallow shafts. Later a prospecting level, Coalcleugh Level, was driven to the High Coalcleugh Vein and cut it at 2,500 ft. from the portal. About 1760 the Barneycraig Horse Level (No. 13) was started and driven for over a mile, giving access to the working of the Barneycraig Vein which came into production between 1808 and 1823. Several other veins were worked in Coalcleugh and Barneycraig, and among them were a number of flats.

These two mines were worked by the Beaumont Company from 1729 to 1878, in which period 187,924 tons of lead concentrates were produced, besides 31l tons of zinc concentrates between 1874 and 1880. The mines were taken over by the Vieille Montagne Company in 1899, and between then and 1920 the production was 6,687 tons of lead concentrates and 52,566 tons of zinc concentrates, with a silver yield averaging 8 oz. per ton of lead. Coalcleugh Mine has recently been reopened for the working of fluorspar, and a new company, the Allendale Metalliferous Mining Company, has been formed for this purpose and for the exploration of 9,000 acres of moorland.

Nentsberry Mine (No. 7A), although partly in Cumberland, should be considered as belonging to this field as its workings extend into the Wellhope area of Northumberland (not to be confused with the Wellhope in Durham). Access was originally through Nentsberry Haggs Horse Level, but a shaft — Wellhope (No. 6) — was sunk in 1925, connecting with the level at a depth of 416 ft. The Vieille Montagne Company took the mine over in 1913-14 and did a great deal of development which led to the discovery of rich oreshoots of average width 6-7 ft., with such individual widths as 20 ft. and 12 ft. Between 1923 and 1928 a total of 277,657 tons of crude ore was extracted, yielding 33,998 tons of lead concentrates containing 80 per cent, lead. Nearly all the ore was treated at Nentsberry mill; difficulty was experienced in separating blende and witherite, and there is still ore of this type left in place. The Non-Ferrous Minerals Development Control (Ministry of Supply) in 1942 established the existence of 54,000 tons of this ore averaging (in percentages) 8.75 zinc, 1.5 lead, and 13 barium carbonate, over widths of 5 ft. and 8 ft. Between 1913 and 1938 Nentsberry production was 39,251 tons of lead concentrates and 4,152 tons of zinc concentrates, with 6.5 oz. of silver per ton of lead.

Durham: Weardale

The earliest definite evidence of lead-mining in this area is Norman. During Norman times Weardale was the property of the Bishops of Durham, and according to the Durham archives King Stephen, in 1135, granted the Minariam de Weredala to Hugh Pudsey, who was bishop at the time. This phrase implies that lead-mining in Weardale was already established; the bishopric had its own mint, and no doubt used silver from the lead. While Cardinal Wolsey was Bishop of Durham he made a valiant but unsuccessful attempt to "melt and try lead with sea-coals" at Gateshead, and in 1527 granted a lease of his furnaces and all his mines in Weardale for thirty years at £5 a year. This sum was paid annually for over a century. In 1696 the mines were leased to the Blackett family, and the ore was smelted by the London Lead Company. At the beginning of the nineteenth century the company leased a number of the mines while the others were leased by Colonel Beaumont, and in 1809 the mines were producing sufficient ore to keep three smelters going. Records name Breckonsike and Wolfcleugh as among the richest mines, the former having produced 4,000 tons of ore in one year, but there is little evidence supporting the alleged prosperity of Wolfcleugh. In 1821 there were 36 mines working in Weardale, and the total production was 6,800 tons. The Ecclesiastical Commissioners took over the ownership from the Bishopric in 1836.

Breckonsike Mine workings (No. 52) were reached from an adit, and the vein was that worked in Allenheads Mine in Northumberland. Originally the Breckonsike Vein was worked opencast, and a sample of fluorspar from the dumps averaged 88.4 per cent. calcium fluoride and 5.05 per cent. silicon dioxide (Imperial Institute, 1941). In 1929-30 a little dump material was taken, but inaccessibility made it uneconomic. Production of galena from 1836 to 1878 was 5,852 tons, but by then the workings were connected with Burtree Pasture Mine, which principally worked the Burtree Pasture Vein and which produced, between 1818 and 1890, about 175,000 tons of concentrates.

Wolfcleugh Mine (No. 32) may have had a wealthy past, but in the recorded period of Beaumont operations, between 1818 and 1846, there is only evidence of 325 tons of galena. The Weardale Lead Company reopened the mine in 1901, and up to 1912, when it was abandoned, succeeded in producing 3,400 tons of fluorspar and 1,639 tons of galena. The company made a further attempt in 1946.

One mine which has worked successfully within comparatively recent years is Boltsburn (No. 38), which for a time was the most important producer of the Weardale Lead Company, owing to the prolific production afforded by the capacious flats. These flats, extending over a distance of two miles, up to 200 ft. in length, 50 ft. in width, and 10 ft. in depth, kept the mine going until 1932, when it had to be closed down on account of increased haulage and winding costs.

Sedling Mine (No. 53) was originally worked primarily for lead, and from 1818 to 1878 the Beaumont Company produced 10,411 tons of concentrates. The Weardale Lead Company produced 6,159 tons betWeen 1889 and 1938, but long before that the galena content of the Sedling Vein had been decreasing with an increasing proportion of fluorspar thus, between 1900 and 1916 (according to Louis), the galena production, 2,708 tons, was only about 4 per cent. of the total, the fluorspar production for that period having been 49,732 tons. From 1900 to 1940 the total fluorspar production was 145,477 tons, and a small, modern, well-equipped mill came into operation.

Two mines which have been reopened in recent years for the production of fluorspar are Stotfield Burn (No. 39) and Stanhopeburn (No. 42). Stotfield Burn was developed by the Rookhope Valley Mining Company between 1863 and 1884, access following the customary pattern of a main shaft with an adit level. Since 1914 work has been fairly regular on the whole, except for intermissions before 1929. The mine is being worked by the Weardale Lead Company, and Dr. Dunham gives the following production figures: lead concentrates, 1863-82, 1,808 tons, and 1932-40,104 tons; fluorspar, 1905-40, 15,168 tons. The neighbouring property, Stanhopeburn, was worked by the Earl of Carlisle & Co., in the eighteenth century, and in the nineteenth century the lease passed to the London Lead Company. The Beaumont Company took it over in 1866 and abandoned it in 1875. In 1906 it was reopened by the Weardale Lead Company, who worked it with some success till 1933. Messrs. Beaston & Elliott again reopened it in 1937, and in 1941 it was acquired by Fluorspar Ltd.

Apart from recording that the Weardale Lead Company opened a new central mill at Rookhope in November, 1949, and is now developing newly discovered veins at Rookhope and Cowshill, we can afford no more space on the Weardale mines, of which, as will be seen on the map, there are, or were, a great number, even though Westgarth Forster lists only seventeen.

Durham: Teesdale

Although there were mines on the Yorkshire side of the Tees, the most productive area was on the northern side, west and north of Middleton-in-Teesdale, where the Whin Sill makes its most southerly appearance at the waterfall known as High Force. The number of mines listed by Westgarth Forster in Teesdale is about correct — ten worked by the London Lead Company and eighteen by minor companies. The London Lead Company was active in the area from 1752 to 1904; there are no figures for the years before 1816, but from then until 1851 the company produced 122,420 tons of lead concentrates. After 1851 the figures for individual mines are available. Barytes was a useful by-product of this district until recent years, when, like fluorspar in the more northern dales, it practically ousted lead ore and became the main product.

Greenhurth (No. 82), one of the most celebrated of the mines, had a chequered history from 1799 to 1868, when it was taken over by the Greenhurth Mining Company which, until the final closing-down in 1902, produced 18,240 tons of lead concentrates, 21 tons of zinc concentrates, and 25 tons of barytes. The deepest shaft was about 500 ft., and assays of the tailings dumps have shown that extraction was efficient.

Cowgreen Mines (No. 116), comprising a number of shafts and adits working several veins, were originally abandoned in 1835, but from 1855 onwards passed through different ownerships. Production periods were divided into the stages 1855-71, 1876-81, 1886-95, and 1898-1920, and the last period embraced the production of Dubbysike Mine (No. 91), 1¼ miles to the north-west on Herdship Fell. In all, 701 tons of lead concentrates was produced (with a silver content of 4.4 oz. per ton of lead), but since 1886 the main product has been barytes, of which the production up to 1920 (chiefly under the Hedworth Barium Company) was 59,123 tons. The Anglo-Austral Mining Company took over the property in 1935, installed modern mining equipment and a mill, and according to Dunham had produced nearly 120,000 tons of barytes by 1945. The entire finished output is used in the manufacture of lithopone, and although in 1939-40 run-of-mine ore averaged 65 to 70 per cent. barium sulphate, treatment of ore with less than 40 per cent. has been found economic.

The Coldberry group of mines (No. 103) was originally worked by the London Lead Company. Coldberry itself produced 45,059 tons of lead concentrates, yielding 3 oz. of silver per ton of lead, from 1852 to 1902, and Red Grooves produced 10,110 tons from 1852 to 1886. After the company surrendered its leases various concerns became interested, but between 1907 and 1912 only 59 tons of ore was produced. The group was explored by English Lead Mines Exploration Ltd. in 1938-39, and although on the whole there seems little likelihood of a future on those veins which were worked, development on other veins has indicated a proved reserve of lead ore in place. The Coldberry Lead Company was registered in 1946 and is still in operation.

Other war-time work carried out in Teesdale included a survey of the Ettersgill zinc deposit, undertaken in 1941-42 for the Ministry of Supply by Non-Ferrous Minerals Development Ltd. Prospecting included diamond drilling and the driving of an inclined drift for 760 ft., and the total zinc content was found by sampling (mainly done by Mr. J. D. Willson) to be 10 per cent. Mr. L. A. Wood and Minerals Separation Ltd., showed that a high-grade zinc concentrate could be obtained by flotation.

Teesdale is separated from Swaledale (the next ore-field to the south) by the extensive structural and topographical depression known as the Stainmore Syncline. The only part of this area known to be mineralised is Lunedale, where a few mines, since the decline in lead production, have yielded substantial quantities of barytes, and it is considered that this area merits further investigation.

Yorkshire: Swaledale

Nothing is known of mining in Swaledale before the times of the Romans, but evidence of Roman working was furnished many years ago when miners at the Hurst Mines (No. 131) holed into old workings and found a pig of lead — said to have been subsequently lost — stamped with the name of the emperor Adrian (Hadrian A.D. 76-138). There are no Saxon records, but Auld, Ald, or Old Gang Mines (O.E. gang road) are thought to have been old in the sixth or seventh century. In the twelfth century, according to a Pipe Roll of Henry II, the mines of Richmond were affiliated with those of Aiston Moor, under the Bailiewick of Carlisle, but this affiliation was dissolved in 1223. In 1182 a Pipe Roll account of the export of lead from Yarm, Teesdale, shows that lead was brought from Arkengarthdale by ponytrack.

There was some confusion over weights and measures in that period. Lead was sold by the "carretate" (cartload) or by the "wey," "waghe," or "vega," and although the common wey was 15 stones the wey of the Richmond merchants was 14 stones. An account of 1294-95 gives the following: "8 waghes of lead and proceeds of a coal mine, 16s. 4d. "6 carretates and 8¼ waghes lead, £7.0s.5¼d."

The lead in question was supplied to the Abbot of Jervaulx for roofing purposes, and, incidentally, as this was the period of greatest expansion of the Yorkshire abbeys, demands like these were responsible in part for the development of mining.

The Grinton Mines (No. 176) are mentioned in a Royal Mandate of 1219 for the protection of the miners and the restoration of the conditions of employment that had prevailed in the reign of Henry II, and there is a record that in 1285 the Lord's Mine (the mine of the Lord of the Manor of Richmond) yielded a profit of £4. In 1396 there was a grant of mines in Downholme, and in 1433 a coal mine for smelting was granted to the Swaledale lead mines. This example of the early use of coal is in itself of interest.

In the sixteenth century there were numerous leases of mines and smelt-mills. Many new mines were opened, the principal operators being the Bathurst family in Arkengarthdale, who built up the "C.B." (Charles Bathurst) group of mines. At that time access to the workings was by means of adits and shallow shafts, but the improvement of winding and pumping methods made possible deeper sinking and the driving of drainage adits at lower levels on the hillsides. The first long level to be made was the Sir George Level (after Sir George Denys), sometimes called the Catrake Mine, at Keld, which was designed to extend from the side of Catrake Foss, on the Swale, to the foot of the deepest shaft at Lane End Mines (No. 156), a distance of three miles. It was entirely dead work through bad ground, and, before it was completed, the mines it was intended to drain were forced to close down, in 1846 and 1849, because of water and lack 'of rich ore at depth.

The early nineteenth century, in fact, was the period of long-level speculation. The Sir Francis Level (Francis was George's brother), driven from a low point in the Gunnerside Beck, led to workings which were equipped with expensive winding and haulage gear, the cost of which, and the cost of development, exceeded the value of ore obtained by £13,000. Work was shared by the Old Gang Company and the "A.D." Company.

Westgarth Forster lists only ten mines in Swaledale — Arkendale, Beldi Hill, Ellerton Moor, Fell End, Grinton Moor, Hurst, Old Gang, Skelhorn, Surrender, and Swinnergill — of which the only two we have been unable to locate are Fell End and Skelhorn. There were, however, as our list indicates, many more mines working at one time or another. The most celebrated was the Old Gang group (No. 168), which had their heyday in the eighteenth century when the area between Reeth and Keld must have presented a scene of bustling industry. Today some of the mine buildings remain in ruins, including the smelt mills, which, in the words of the late Ella Pontefract, "add to the grandness of the stretch of moor as a ruined abbey adds to the beauty of riverside meadows." Another relic is a flue, half a mile long, for the collection of fume. In 1933, unfortunately, four archways above the furnaces were pulled down and the stone used in the building of a Methodist chapel.

Women were employed for carrying the ore in baskets ("kibbling"), washing and separating, and gleaning, and in the seventeenth century their wages consisted of a shilling a week and two flannel petticoats a year. In spite of the conditions and lack of regulations, accidents are said to have been few.

Hurst, where the Roman pig of lead was found, is like Goldsmith's Deserted Village. It is full of sad ruins, but its saving grace lies in the thatched roofs of the cottages. Miss Marie Hartley has an old account book for "ye Leade Works" at Hurst for 1660-63, when as many as 31 miners ("grovers") and two or three women were employed. Yearly earnings averaged £13, but could be as high as £63. It is little wonder that today the fells of Swaledale are so sparsely wooded, for in the accounts there is evidence of packhorse men bringing hundreds of "sacks of chopwood" and "dozens of timber," and it is highly probable that much of this wood was burnt for fire-setting. The last recorded production of Hurst Mines was in 1880, with 55 tons.

Hunt gave the following figures for production of lead ore in Swaledale: 1857, 5,537 tons; 1858, 6,576 tons; 1859, 5,717 tons; and 1860, 4,878 tons. He said: "Distributed over an area of about 200 square miles, there are 192 distinct veins known in Swaledale, and of these 170 are returned as having produced lead." The period of greatest productivity was over in Hunt's time, however, and he listed only twelve mines.

Yorkshire: Wensleydale

Wensleydale differs from the other Northern dales in that its modern name is derived not from the river flowing through it — the Ure — but from a village. This was not always so, however, for before the nineteenth century the valley was known as Yoredale, but even the name of the river gradually became corrupted from Yore to Ure. The name Yoredale is still retained, of course, in the series of beds lying between the Millstone Grit and the Carboniferous Limestone.

Wensleydale, on the whole, has suffered less deforestation than its neighbour, Swaledale, so that its aspect is less forbidding and its slopes more immediately attractive. Lead-mining has not been on such a scale as in Swaledale, but many of the hillsides are deeply scarred with the signs of hushing. The richest veins were on the edges of the high moors; there was no mining below the water-table, and all drainage was through adits. In spite of that the shafts reached considerable depths, and at Keldheads (No. 184), for instance, it was 960 ft. from adit level to "bank."

The mining areas, with exceptions, were mostly north of the river, in the district north-west of Askrigg and in the tributary valley of Apedale. Westgarth Forster lists eight mines — Apedale, Keldheads, Longcleugh, Penhill, Sargill Side, Walden Head, Worton, and a mine bearing the safe name of "York and Lancaster United" — of which the third, sixth and last have defied search.

Mining is known to have been carried on in Wensleydale as early as the twelfth century, when certain mining rights were held by the monks of Jervaulx Abbey. The oldest mine in the dale was Sargill (No. 161), two miles west of Askrigg, which was once owned by two brothers Winn, a parson and a lawyer, who, according to Miss Pontefract, built a smelter to save them the trouble of carting the ore to Swaledale. When the ore appeared to be nearing exhaustion they gave their mine to a miner on condition that if he found ore he would pay them so much a bing (8 cwt.). The miner thereupon hushed the hill, uncovered a new vein, and made a fortune. Sargill was finally abandoned in 1886.

The relatively small amount of mining done in Wensleydale leads one to think that further exploration might be profitable. The most active district was Apedale, which today presents a familiar scene of desolation all too common. Most of the miners lived around Redmire and Castle Bolton, and the present custodian of Bolton Castle (once the prison of Mary Queen of Scots) has a fund of information about the mines. The moor still bears evidence of the effect of lead fume, although damage to farms was prevented by the construction in the eighteenth century of a flue two miles long from Keldheads smelt-mill. Keldheads was the biggest mine in Wensleydale; it once employed over three hundred men and in one year produced 1,374 tons of lead. Up to recent years there were old men living who had worked in the mines when a beginner received eightpence a day, a more experienced man a shilling, and a fully-fledged miner half a crown. They often worked in partnerships for so much a fathom or a bing.

It is of passing interest to note that, in Yorkshire generally, a miner could prospect anywhere except in private walled grounds, and if he found a vein of ore he became the owner, or "mere-man," the mere measuring 27 to 32 yards along the strike. He was the mere-man only as long as no period greater than one month passed without the erection of timber in the mine.

Lead Mining in Alston Moor
Mine and Quarry Engineering, February, 1938 

Some account of the operations at the Rotherhope Mine of The Vieille Montagne Zinc Company, Cumberland

Alston Moor is particularly rich in mining traditions. The fact that the district is traversed by the Maiden Way and contains the support camp Alstonioni points to Roman operations, for the gossans were rich in silver, as subsequent history shows. That no direct trace of Roman workings has been found is not surprising, for the whole district has been scoured for hundreds of years and early diggings would naturally suffer total obliteration. It was the practice too, in past generations, to resort to "hushing" and the huge scars torn into the hillsides where veins outcropped would sweep away all evidence of shallow workings. The only pointer towards Roman activity is a long mound of slag, definitely ancient and in all probability the refuse from lead smelting operations, within a few miles of the camp and lying between the latter and the mineralised terrain.

Of medieval mining, history is equally blank and while certain place-names may or may not be evidence of German or Saxon miners brought over to work the mines, it is not until Tudor times that our footing is secure. Cardinal Wolsey in the reign of Henry VIII had dealings with the lead mining areas of the North. There is abundant evidence in Elizabethan times that the mines — the Queen's Silver Mines as they were called — were important contributors to the Royal Revenue.

Much data, in the way of minute books, plans, account books, etc., exist regarding the activities of the London Lead Company.* On October 4th, 1692, William and Mary granted a Charter for "Incorporateing the Governour and Compa for smelting downe of Lead with Pittcoale and Seaacoale." From that date to the year 1905 when the affairs of the Company were wound up, this variously named mining corporation (known as the Bristol Company, The Society of Royal Mines — Copper, and the Ryton Company, the Quaker Company and finally as the London Lead Company) conducted operations in England, Wales, Ireland, the Orkneys, Scotland, and the Isle of Man. Their connection with Alston Moor and its lead mines extends over a very long period of time. Early in the eighteenth century the Company were operating lead mines and smelters in Alston Moor. The forfeiture of the Earl of Derwentwater's estates to Greenwich Hospital after his participation in the Jacobite Rebellion of 1715, enabled the Company to considerably extend their leases in the area, which now became their most important centre.

A general decline in lead mining set in towards the end of the nineteenth century and eventually the Company sold their interests to the Vieille Montagne Zinc Company who still maintain their connection in the area.

Geology of the district

Numerous veins carrying lead ore occur in the Mountain Limestone series of the Pennines which, on that account, are sometimes termed the Lead Measures. They consist of a succession of beds of limestone shale and sandstone (known locally as hazle) and dip slightly eastwards. The various limestone beds are well characterised and permanent over large areas ; the Great Limestone, which averages over 60 ft. in thickness, is the most important. At a point relatively low down in the series occurs the Great Whin Sill. This intrusive sheet of dolerite is general throughout the greater part of the area and outcrops in certain places. Generally it has been found that the veins have not been productive below this sill, but there are a few cases where it has been mineralised. Rotherhope is one of these exceptions, lead having been mined in the Sill and in the Jew limestone. The most productive veins in Alston Moor extend from East to West and although other veins running North and South occur, they are not so productive except perhaps at the points of intersection and for some little distance beyond. In certain areas in the district these fissure veins are characterised by their habit of "flatting," i.e., the formation of horizontal beds or sheets of ore. These "flatts" lie between the strata in much the same manner as coal seams. Well defined walls are not present, and, as limestone gradually makes its appearance among the ore, the latter becomes progressively less until only fine particles of galena are disseminated throughout the limestone. Apparently these flatts have been caused by the mineralising solutions laterally traversing the horizontal planes of weakness following the joints of the limestone.

Rotherhope mine

This mine has had a long and varied history and it is proposed to give some little account before dealing with present-day operations. It is situated about 3 miles south-west of Alston and some 7 miles from Cross Fell, the highest point in the Pennines. On the property are two main veins — the Rotherhope and the Victoria — running almost east and west.

The Rotherhope vein has been proved over a length of 6,808 ft. along its strike. The average throw is 24 ft., north cheek up. This vein can he distinctly traced along its outcrop and has been productive in various sills. At the extreme point east it has been considerably influenced by Sir John's vein and is broken up and poor. At the West End the vein has been disturbed by a cross-course, and although this interference may have caused "flatting" of the vein to occur, it seems more likely that the vein in this random had this habit without any interference from the cross-course. These flatts occur on either side of the Tyne Bottom limestone. On an average the vein width varies from 10 to 20 ft., the walls being somewhat ill-defined. The vein filling is galena with which is associated fluorspar and calcite. Blende is very rarely met with. In the past the old miners drove a level to intersect these veins in the top random. Most probably by means of small winzes they would ascertain if the veins were mineralised at lower randoms and a second, or Middle, level was driven a distance of 3,600 ft. This level would have the advantage of the 5-yards limestone, the 6-fathom hazle and the 3-yards limestone. Both veins were driven on from this level and it is understood were extremely productive, especially in the Scar limestone lying just below the level and being 5 to 7 fathoms thick here. During the operations a ventilation shaft was put up to the surface a distance of approximately 31 fathoms — and would prove the upper values. Afterwards this shaft was put to further use as will be mentioned later. Operations at further depths proved that the Rotherhope vein was still productive, but there is little evidence of extensive workings below the Middle level in the Victoria vein, nor is there evidence to prove that the workings on the lower Middle level random were sufficient to connect the present adit level. This, known as the Blackburn level, was commenced in 1837 according to the date on the keystone at the adit mouth, and was driven approximately 4,200 ft. where it now connects with the shaft from the Middle level and also the surface. It is interesting to note that 3,000 ft. of this adit is perfectly straight and a good example of surveying and driving when taking into account the equipment available in those days. At the 3,000 ft. point the Victoria vein was intersected. Here the level is in a section of strata of the Lower Carboniferous series and is driven in the alternating beds below the Scar limestone which at this section consists of hazle and plate or shale with portions of limestone in two places. The latter rock would impede the progress somewhat and, according to reports, it took 6 years to drive the 4,200 ft. length At the latter point the Rotherhope vein was intersected, good values were encountered and fairly extensive workings east and west are in evidence, A shaft was sunk at this point through the Tyne-bottom plates and the Tynebottom limestone. The result of this was to prove that the vein had "flatted" in the limestone and was carrying good values. The shaft was further extended through the Great Whin sill, which is 120 ft. in thickness, but the ore values at this random were not very rich. Drives east and west were put forward for short distances and a hydraulic engine was installed for winding and pumping duties. Another shaft North of the vein was sunk to a depth of 20 fathoms and was connected at the bottom with the other shaft. By this means the flatts in the limestone at the 10-fathom random were made more accessible while elaborate accommodation was made for a second hydraulic engine installed for winding and pumping at this second shaft top. The engine house, an example of excellent workmanship, is approximately 36 ft. long by 21 ft. wide by 24 ft. high. These are inside measurements of a large arched structure with other arched entrances. Here it should be stated that pumping is necessary from the levels below the Blackburn adit. The first engine pumped the water to the 20-fathom random and the second engine pumped it to the adit level. This latter engine was fitted with an 8 in. clack and bucket set and also had a compressor attached. A hydraulic pipeline from the reservoir at surface passed down the air shaft via the Middle level to the engines. Later a 6 in. dia. pipeline supplied water to a Pelton wheel driving a Cranston compressor installed by the present company. Just before the Vieille-Montagne took over the property someone maliciously liberated the water from the reservoir with the result that the air shaft was wrecked from the surface to the Middle level and another shaft had to be sunk and a new pipeline installed. After a preliminary survey, operations on this second shaft were commenced by sinking from the surface and by rising from the Middle level, the two portions meeting almost exactly. A hydro-compressor was installed underground, as the shafts connecting the surface and Middle level, together with the existing reservoir, provided the necessary requirements for such the hydro-compressor is still working satisfactorily. This installation enabled machines to be employed for drilling and also supplied compressed air to the pumps. In addition a water-blower pump was installed to relieve the clack and bucket pumps then in use.

When the Vieille-Montagne took over from the Rotherhope Mining Company they commenced to develop the East 20-fathom random and encountered good values. A shaft was sunk from the main West End adit level into the Whin Sill where good values were also proved. Such were the prospects that a new dressing floor was eventually erected at surface and the mine ore ("bouse" as it is termed locally) was stored outside.

For a long period operations had been conducted on the Rotherhope vein itself but flatts were discovered in the West End section on the north and south sides of the vein. The South flatt was approximately 22 ft. lower than the flatt on the north side, owing to the existing throw of the vein. Fairly good values were obtained from these flatts. Owing to the ore having to be trammed back to the West End shaft by means of an intermediate level and hoisted from thence a distance of 20 fathoms to the Blackburn adit level, an incline to connect the two flatts with the adit level was commenced at each end (the top and the bottom) the top portion went down 3 or 4 ft. below the limestone. These two inclines were not connected because, owing to the low price of lead, operations on a large scale ceased in 1930. The pumps were kept going with air from the hydro-compressor until November, 1934, when the mine closed.

Present-day operations [circa 1938]

An improvement in the Base Metal Market had the result of re-opening the mine in October, 1935, when it was the intention of working the North and South flatts again. Pumps were put to work and eventually the water was mastered. The water-blower pump mentioned above was found to be a great asset in these un-watering problems. A bad fall was encountered in the main level West and a fork level was driven to avoid it. While this work was in progress, parallel vein strings approximately 6 to 8 ft. apart were encountered some of these carried small quantities of galena. After getting into the main level again, another bad fall was encountered but this was beyond the north side incline. The strings found in the fork level led the management to expect these would feed flatts. Development to prove this commenced at the bottom of the incline with the result that an extensive section of flatts was discovered. A forebreast was driven approximately 40 fathoms from the vein and good values were found. Six rock drills, working double shifts for the last eighteen months, have been in operation on this section, which is still showing good values.

At the other shafts, the water was lowered below the 10-fathom random and, expecting the vein to behave in the same manner, exploratory work on the outskirts of the old miners' flatts was put in hand. Within a week evidence of further values was obtained but the lack of power was beginning to be felt and a new installation was decided upon. The old hydraulic engine was scrapped and the elaborate engine house used to accommodate the following plant :— a 130 h.p. Metro-Vick slip-ring type motor at 970 r.p.m. is driving a 3-cyl., 11½ by 12 in. Broom and Wade compressor giving 600 cu. ft. free air per min. at 325 r.p.m. A similar make and type of motor but of 100 h.p., and running at 965 r.p.m. is driving a 3-cyl., 10 by 12 in. Broom and Wade compressor giving 450 cu. ft. free air at 315 r.p.m. In both cases vee-rope drives are employed. Power is taken from the Mid-Cumberland Electricity Supply Co. Ltd., at 11,000 V direct to the engine room which, as already stated, is 1,400 yards from the adit mouth. Metro-Vick transformers step the current down to 400 V and 1 10 V for power and lighting respectively. Starters and motor slip-rings are interlocked with the main starting switches.

The lower 10 fathoms section of the shaft was converted into a ladderway and hopper as the water was still being lowered to the 20-fathom random. A drift was started at the 10-fathom random in the bottom of the limestone where evidence of a flatted vein with traces of galena were present. After driving 4 ft. 6 in. to the North, a parallel string approximately 2 in. thick was cut through; this immediately mineralised the flatt. A distance of 80 ft. has been taken out as a flatt 20 to 24 ft. wide and the indications are that this will prove to be a rich block of ground ; two other flatts are being taken out each in opposite directions (East and West) and all are giving good values. In the foremost flatt (i.e. North) another string has just been passed through and evidence exists of richer values. Between the East and West sections of the flatts there is a distance of approximately 350 yards while the shaft at the East section is 20 fathoms deep at this random. An existing level to the West provides a favourable point of attack on the North and South flatts lying midway between the two sections and a rise is being put up to prove these values.

Timbering in these flatt deposits is governed entirely according to conditions prevailing. It has been found that timber frames, well packed with "deads," form the best supports.

Throughout the mine Atlas drills are in use and 1 in. dia. hollow hexagon drill steels with rose bits are employed. Steels are sharpened by Holman Twin-Grip drill sharpeners.

The new installation is working very smoothly; a constant supply of air at 85 to 90 lb. per sq. in. pressure for the drills and hoists is and has been of tremendous assistance in obtaining maximum efficiency. Prospecting, development, and the breaking of ground for milling ore have all been considerably facilitated.

Extraction

All ore broken in the flatts is loaded into 18 cwt. capacity wagons and hand-trammed to the air hoists which raise it to the Blackburn level. Here, horse transport is employed, the loaded wagons being drawn out of the mine on this level direct to the mill.

Milling operations

The mill is situated some 800 ft. from the Blackburn adit mouth and has a present capacity of 7 tons of mine ore per hour. Hand picking, crushing and screening, coarse jigging and slime treatment are allowed for in the design; classification is carried out wherever possible.

On entering the mill, the crude ore is tipped over a set of grizzley bars which are spaced with 4 in. openings. Undersize is sent direct to a storage bin of 25 tons capacity. Any waste rock in the oversize is eliminated by hand picking, the remainder being reduced and sent to the storage bin. From here it is automatically fed to a revolving screen or trommel and graded in the following sizes :— 15 mm., 25 mm., and 50 mm. The fines, up to 15 mm. in size, go direct to the elevator, while the other two screen products are passed over revolving picking tables where pieces of clean, high-grade, galena and waste rock are taken out. After this the 25 mm. size is sent to rolls for reduction to minus 15 mm., while the 50 mm. size passes through an Ord and Maddison jaw crusher, any oversize (plus 15 mm.) from this crushed product going to the rolls for further reduction. All is now elevated to another trommel and graded into 10/15 mm. 5/10 mm., and minus 5 mm. sizes. The 10/15 and 5/10 mm. sizes are dealt with in the first and second rough jigs respectively. These jigs produce concentrates of well over 80 per cent. Pb. content from the first hutch, while the middlings are passed through rolls and then sent back via the trommel for further grading and jigging. The minus 5 mm. size goes to another trommel and is graded into the following sizes :— minus 2 mm., 2/3 mm., and 3/5 mm. Of these sizes the 3/5 mm. is jigged to produce a concentrate, the middlings being elevated, ground in a Hardinge mill and classified for table treatment. The 2/3 mm. size is jigged and a concentrate produced ; middlings are sent to a Hardinge ball mill and thence to the slime plant. The minus 2 mm. size is sent to a classifier, the overflow from which goes to the slime plant, while the 1/2 mm. is jigged to produce a concentrate and the middlings are also ground in the Hardinge ball mill before being passed to the slime plant. After leaving the Hardinge mill, further classification is effected, the coarse or sands product being treated on Wilfrey sand tables and the fine overflow being treated on a James Slimer and two round slime tables. In this way a fine lead (slime) concentrate is produced.

Concentrates are produced in the following sizes :— 5/15 mm., 3/5 mm., 1/3 mm., and slime lead. Apart from the slime galena which assays somewhere about 78 to 79 per cent. Pb., the bulk of the concentrates assay around 84 to 85 per cent. Pb. This is a very high-grade galena which is carefully selected, dried and packed in double bags before despatch.

A certain amount of revenue is obtained from the sale of some of the tailings, or waste, from the jig and tables. These comprise graded chippings and sands and, being of hard limestone, washed and entirely free from dust, are of very attractive appearance and quality.

Power plant

Advantage of water power is taken whenever possible. Over a very wide area the water is collected from the surrounding hills and stored in two reservoirs on the Rotherhope fellside. An 80 h.p. pelton wheel working under a 194 ft. fall of water and a Gilkes turbine capable, when the race is full, of developing 70 h.p. under a 64 ft. fall of water, are installed. In addition there is a twin-cylinder Campbell fuel oil engine of 175 b.h.p. This engine formerly drove air compressors for the mine and also took a certain amount of the mill load. Now the new underground installation is running, the engine will be used as a standby for the mill when supplies of water for the Pelton and turbine are running short.

In concluding this account we wish to say that Rotherhope cannot be termed a rich mine in the accepted sense of the word. The outlook is promising and, on the whole, the mine is in a healthy condition. It has had a long history, has produced much galena, and the monthly output is now consistently increasing. Exploration is being steadily pushed ahead in order to prove the existence of further ore bodies in the flatts. To what extent these may prove to be, and if they are richly mineralised, no one can say with certainty. But that is the fascination of metalliferous mining.

It is interesting to record that the Vieille-Montagne, who, in 1896, took over the Nenthead mines (Alston Moor), recently attained its centenary. One of the oldest established and most important of European zinc concerns, it was formed in 1837 and takes its name from the original mine at Moresnet, known as the Altenberg mine, of which "Vieille Montagne" is the French rendering. This mine, although operated continuously since the fifteenth century, has always yielded considerable quantities of high-grade calamine, blende and galena. It was at Moresnet, 70 years ago, that compressed-air operated drills were first used, as were also nitro-glycerine, dynamite and similar explosives. Wolf installed his first double cylinder pump at Moresnet and it was there Kley constructed his first rotary pumps with variable discharges. Today, this Belgian firm of world-wide ramifications possesses mining properties in France, Sweden, Italy and North Africa, and has controlling interests in mining concerns in Norway, Italy, Spain, Greece, Mexico and Indo-China. An affiliated company owns the German Bensberg (Rhineland) property. The first company in Europe to undertake the production of electrolytic zinc, the Vieille-Montagne possesses extensive reduction plants in Belgium and France. These comprise smelting plants producing ordinary and special grades of zinc, rolling mills, zinc oxide plants, a lead refinery equipped for the recovery of silver and the manufacture of sheet and pipe lead, and roasting plants where sulphuric acid, nitric acid and super-phosphates are produced.

We desire to thank the Vieille Montagne Zinc Company for facilities to visit the property and to take photographs. We also wish to place on record our appreciation of the kindness extended to us by the Manager, Mr. A. Treloar, and his staff on the occasion of our visit in this connection we would mention Mr. Hugh Millican, in charge of the underground operations at Rotherhope, to whose good offices we are indebted for much of the information incorporated in the article.

* The London Lead Company, 1692-1905. By A. Raistrick, Ph.D., F.G.S., M.I.Min.E. Trans. Newcomen Society, Vol. XIV. 1933-1934.



Please help beat cancer - DONATE click above

 

A STEAMPUNK NOVEL, FULL OF
ANARCHIC EXPERIMENTAL SCIENCE


"Hodges emitted a scream the like of which
I hadn't heard since his scrotum was burned off
during my experiment with fluorine gas last year."


The Exotic Experimentation of Ernest Glitch,
Victorian Science with a Smile

More information & sample chapters here

Search for Ernest Glitch on your Kindle
or visit Amazon -
UK here
USA here


Unrelated to this post, below is an example of
eclectic science esoterica 




Main Menu - click above
WARNING - Many subjects outlined within this site are extremely dangerous and are provided here for information only. Please don`t experiment with high voltages or chemicals unless you are fully conversant with safe laboratory practices. No liability will be accepted for death, injury or damage arising from experimentation using any information or materials supplied.