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February, 1938

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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 mediaeval 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 Comp^a 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

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.

Drawings and Photographs accompanying the article