Printer Friendly

The Alva silver mine, Silver Glen, Alva, Scotland.

A little-known, long-abondoned mine in central Scotland has recently yielded some remarkable specimens of crystallized native silver. Its history is every bit as remarkable. The deposit, first opened in 1715, ranks as the richest bonanza of native silver ever found in Britain.

INTRODUCTION

When mineralogists are asked to name European localities for crystallized native silver, most will list well-known mining districts such as Norway's Kongsberg and Germany's Harz Mountains. Very few will even have heard of Scotland's Ochil Hills, yet a small but spectacular find there in 1715 yielded dendritic silver as beautiful as that from many of the more famous continental mines. In the same year, Britain was wracked by a bloody uprising as two would-be monarchs competed for the throne - George I, Elector of Hanover, on the government's side and James Edward Stuart, "The Old Pretender," son of the deposed James II, heading the Jacobite rebels. This coincidence led to a remarkable sequence of events involving fortunes made and lost, buried treasure, betrayal, deals with the Hanoverian government, and a diversity of charming and not so charming characters.

HISTORY

The central character of the story was Sir John Erskine, who lived at Alva House at the foot of the Ochil Hills, about 10 kilometers east of Stirling in central Scotland. A distant descendant of the great Scottish hero Robert Bruce (who slaughtered the English in 1314 at Bannockburn - one of the few times Scotland actually won a battle against its southern neighbor), he was born around 1672, the second son of Sir Charles Erskine and his wife Dame Christian Dundas. According to John Ramsay of Ochtertyre, "He was a man of wit and genius, but the heat and volatility of his fancy would not be regulated by prudential considerations" (Allardyce, 1888). His elder brother, Sir James, was killed at the battle of Landen in 1693. His brothers included Dr. Robert Erskine (1677-1718), physician to and favorite of Czar Peter the Great of Russia, and Charles Erskine, Lord Tinwald, later Lord Justice-Clerk, who shall enter the story later.

In 1714, Sir John brought a miner from Leadhills to survey his estate at Alva for minerals. Around Christmas he found a promising mineral vein in a small glen just 10 minutes walk from Alva House. Mining commenced early in 1715. The work had barely begun when the miners noticed strings of a metallic ore which, when followed, led to a mass of solid ore. Analysis of this proved it to be extraordinarily rich in silver, 14 ounces of ore yielding 12 ounces of the metal according to Duncan (1796) who said that the ore consisted of native silver, adhering "in slender strings to the spar, in a variety of fanciful and irregular forms."

At this same time the Jacobite rebellion was breaking out and Sir John's cousin, the Earl of Mar, was organizing the rebels. Sir John too supported the cause, and he went off to join the uprising, leaving his wife, the Hon. Catherine, second daughter of Lord Sinclair, in charge of the mine. Sir John seems to have spent much of the rebellion in Europe, as we shall see, rather than in combat alongside the Earl.

After raising the Standard at Braemar in September 1715 the Earl headed south to confront the government forces led by the Duke of Argyll. The two armies clashed at Sheriffmuir about 8 km noah of Stirling on Sunday the 13th of November. The churches were silent that day, and the minister of Alva sent a message to Alva House that "There wad be nae Sabbath the day" (Hynd, 1981).

The battle was indecisive, and when the rebels heard that their comrades in England had been defeated that same day at the battle of Preston things must have looked gloomy. Sir John, however, was safe in France. While he was away, Lady Erskine tended the wounded from the battle, employed spies for the rebels and, of course, supervised the working of the mine. To operate the mine, the Erskines had employed one James Hamilton to oversee the labors of the workmen. When the rebellion broke out the mine had penetrated a mere 4 or 5 yards underground and had produced only 134 ounces of silver, but during the rebellion Mr. Hamilton and his men were busy. Acting under Lady Erskine's orders they dug out, in the space of three or four months, some 40 tons of ore and buried it in barrels near the gate of Alva House for safekeeping (Hamilton, 1716).

While Lady Erskine was taking care of this wealth, Sir John was busy in Europe gun-running and gold-smuggling for the rebels. There he remained for several months, and was frequently hard up for cash despite repeated attempts by his wife to make arrangements for [pounds]100 to be passed on to him. In her letters Lady Erskine assures her husband that the estate is in good order, the hedges and ditches maintained and the crops sown but she avoids any direct mention of the silver mine, perhaps in case her letters should fall into the wrong hands. There are, however, veiled references. Lines like, "Mr. Nabit does not employ old H or any of his profession at present" and, "It is yet impossible to tell what money Mr. Nabit will be worth, his reputation amongst the common sort is so high that no body credits it" (Erskine, 1716a) seem quite innocent until one realizes that "Nabit" (nowadays "Nebit") is the name of the hill on which the mine is situated.

Sir John's predicament looked grim. He was deeply involved in the uprising and was a wanted man. Ironically it was to be a betrayal by mine manager James Hamilton that was to provide Sir John with a pardon and permission to return home. On June 18th, Lady Erskine had written to her husband ". . . James went away three months agoe, for he turned wrong in the head and would not stay" (Erskine, 1716b). Hamilton traveled to London and deposited an affidavit dated July 3, 1716 with the Lord Mayor of London, Sir Charles Peers (Hamilton, 1716). This affidavit gave details of the silver mine. He took with him some samples of the ore which aroused much interest on account of their great richness.

This upset Lady Erskine greatly, and on July 8th she wrote to her husband, "It ha's grievd me very much, and it is no small satisfaction that it has not failed by any neglect of mine but he certainly designed to comitt the villainy and went away with that veiu for nothing I could doe could make him stay" (Erskine, 1716c). However, the Erskines and their friends were quick to turn this to their advantage. They exploited an old Scottish law that said that a tenth of the proceeds from any mine of gold or silver was to go to the crown. It was argued that Sir John had more knowledge of the silver mine than anyone else and that if he were pardoned and allowed to return he could resume mining with 10% of the revenue going to the government.

The government agreed and decided to send someone to inspect the mine and report on it. At first Sir Isaac Newton, Master of the Mint, who had assayed some of Hamilton's samples of ore and described them as "exceeding rich," was asked. He declined on the grounds that he was "unacquainted with these matters" (Newton, 1721). The government decided to send an expert from the king's silver mines in Germany instead. So it was that one Dr. Justus Brandshagen was given instructions to travel to Alva and inspect the mine. He was to be accompanied by James Hamilton and James' brother Thomas, and was to be paid a pound a day and the Hamiltons half this.

Brandshagen set sail on September 10th and 23 days later, after a stormy voyage in which his ship lost two masts, he arrived in Scotland. In Edinburgh, on October 15, 1716, he met the Earl of Lauderdale who informed him that Sir John had obtained his pardon on condition that he show Dr. Brandshagen the mine. They decided to wait until Sir John returned to Scotland before proceeding to Alva.

The inspection of the mine began on Tuesday, November 13. A detailed journal (Lauderdale et al., 1716) described what followed. The Earl of Lauderdale, John Haldane of Gleneagles (Sir John's brother-in-law), William Drummond (Warden of the Mint at Edinburgh), Dr. Brandshagen and James Hamilton met in Alva House. Sir John then took the gentlemen out to the site of the mine only to find that it had been filled in with earth and rubble. Accordingly, six local workmen were employed at ten pence a day to clear the debris from the workings. The men were expected to provide their own tools for the task.

The following day, while some of the men were busily engaged in excavating the mine, James Hamilton and two workmen were called to Alva House for the purpose of exhuming the 40 tons of ore said by Hamilton to have been buried there. Mr. Hamilton indicated the spot - on the northwest side of the house, near the gate - and said that there was but 6 inches of soil on top of the barrels of ore. The men set to work but after digging to over a yard depth in two places in the already loose and disturbed soil with only a few fragments of ore to show for their efforts it was apparent that the casks of ore had gone.

At this point Sir John guided the men to his garden and showed them a spot where he said his servants had told him there was some remaining ore buried. Being late in the day the excavation of this spot was postponed until the following morning when the Doctor, together with the Hamilton brothers and the workmen accompanied Sir John and his servants into the garden. There the men dug and rapidly uncovered six small casks filled to the brim. The contents were emptied out and were found to consist of little more than worthless waste rock from the mine. The servants, upon being questioned, said that the other casks had from time to time been dug up and taken away but to where they knew not. Curiously, this matter seems not to have been pursued further by the authorities, nor is there any indication that Lady Erskine was questioned.

In the following weeks, the mine was cleared and furnaces constructed for assaying the ore. The Earl of Lauderdale, together with Mr. Haldane and Mr. Drummond, returned to Alva on January 2, 1717 and, accompanied by the Doctor and the Hamiltons, went to the mine, where the Hamilton brothers took samples of ore from six separate parts of the mine. Portions of these samples were dispatched to London while the remainder were assayed over the following days by the Doctor and James Hamilton. While not approaching the legendary 12 ounces of silver in 14 ounces of ore the assays were nevertheless extremely encouraging, giving up to 6% silver. Dr. Brandshagen said of the ore:

I found it of an extraordinary nature, such as to my knowledge few or none like have ever been seen in Europe. It consists of sulphur, arsenic [sic], copper, tinn [sic], iron, some lead, and good silver. Of all these the silver is only to be regarded, for the other minerals and metals contained in the ore are of little value, and not worth the charges to separate and keep them. (Brandshagen, 1717)

The Doctor seems to have been well pleased with his treatment, for in his report to the Lords of the Treasury he wrote:

Sir John Areskine . . . has all along been not only particularly civil and kind to me, by procuring me and my family and the Hamiltons good lodging and accomodation near the mine, in the minister of Alva's house, but likewise in accomodating us sometimes with necessary tools, with work people, and with a house where we built the furnaces and made the assayes, and he contributed in everything to facilitate and carry on this business. (Brandshagen, 1717)

The government too was satisfied and allowed Sir John to stay; the mine was worked for several more years. Gradually the remaining ore diminished and gave way to poorer ores of copper and lead that were uneconomical to work, and the mine was abandoned.

With his fortune from the mine (reputed to be [pounds]40,000 to [pounds]50,000 which, at the prevailing price of 5s 2d an ounce, would correspond to 5 or 6 tons of silver), Sir John embarked on ambitious improvements to his estate. He planted the hill behind his house with native and exotic trees, made extensive enclosures and agricultural improvements and, at great expense, dug a canal to facilitate the transportation of coal from pits along the River Devon to the River Forth. When a neighbor remarked, "Sir John, all this is very fine and very practicable, but it would require a princely fortune," Sir John replied, "George, when I first formed my scheme of policy for this place, I was drawing such sums out of the mine that I could not help looking upon the Elector of Hanover as a small man" (Allardyce, 1888a).

In 1739 Sir John died after a fall from his horse. The estate passed first to his eldest son Charles, who was killed at the battle of Laffeldt, and then to the next eldest, Sir Henry or Harry Erskine, baronet, Member of Parliament, and later lieutenant-general in the army. He sold the estate to his father's brother Charles (Lord Tinwald) in about 1749.

Charles, Lord Tinwald (1680-1763), was the ablest of the brothers. Pursuing a career in the legal profession, he rose to Lord Justice-Clerk in 1748. Ramsay of Ochtertyre described him as "possessed of excellent talents, which were improved by culture, and set off to great advantage by graceful persuasive eloquence in a strain peculiarly his own." He was witty, polite, even-tempered and his oratorical skills earned him the nickname "Sweet-lips" (Allardyce, 1888).

He also shared some of Sir John's speculative spirit. He suggested, "If one could turn over the Ochils like a bee-hive, something might be got worth while" (Allardyce, 1888). So it was that in about 1758 he, together with some relatives and friends, formed a company to rework the silver mine which had lain idle for many years. Their workmen followed the course of the vein for a good distance beyond the site of the original bonanza. They also explored several other promising veins in the glen.

In spite of the extent of these endeavors only traces of silver were found; in addition, the workings kept flooding. It was resolved to drive a tunnel into the hillside lower down the glen to drain the upper workings. This had progressed only a short distance when the miners encountered what at first they took to be a second bonanza. A large mass of bright pink ore, "the colour of peach blossom," was found. A sample was sent to the eminent Scottish chemist Joseph Black who identified it as an ore of cobalt (Black, 1759).

Further samples were sent to a Mr. Nicholas Crisp in London who carried out many assays and described it as "a good cobalt ore" and said it was comparable to that obtained from the mines of Saxony - the main supplier at the time. "The Cobalt vein," he said, "contains very good lead, very good Copper and three different kinds or such of very good Cobalt" (Crisp, 1762). These ores all contained silver - up to "29 lb in the tonn Wt." (Crisp, 1761a) and this silver in turn contained "Gold in some considerable quantity" (Crisp, 1761b). This ore was extracted and sold to a company near Edinburgh who used it to produce a deep blue color on porcelain.

After Charles' death in 1763, the estate passed to his second son James, Lord Alva. (The first son, Charles, had been killed when he jumped out of a window in London while delirious with a fever.) James continued working the mines and, when it was observed that the waste from Sir John's workings from about 40 years earlier also contained cobalt, be ordered this to be recovered. In 51 days of washing and picking the waste, two miners, John Weir and James Logan, filled seven casks with cobalt ore and recovered "a small box of silver" which "did not exceed a stone(*) weight." For this work they were paid two pounds and eleven shillings (Anonymous, 1766).

As with the silver, the cobalt deposit was soon exhausted. The work was continued for a considerable distance beyond the site of the discovery but no more was found. The company was also running into financial trouble. One of the partners, Sir Henry Erskine, died in 1765 and another, Mr. Crisp, despite his initial enthusiasm, stopped paying his contributions. In 1768 another shareholder, John Stephenson of Hull, wrote to Lord Alva, "It has been great concern to me to find our Cobalt company decline to nothing" (Stephenson, 1768) and later another partner, Leith merchant Alexander Shirreff, pulled out. By now incurring a substantial loss, the mines were abandoned again.

In the 1770's, Lord Alva sold the estate to the immensely wealthy John Johnstone. His family made many improvements to the estate but did not attempt to reopen the mines. The Johnstone line ended with Miss Carolin Johnstone, who died in 1920. Unfortunately she overspent and when she died the sale of the house contents and the estate was insufficient to clear her debts. Sadly the huge house could not be sold and was demolished during the Second World War.

GEOLOGY AND GEOGRAPHY

The Ochils are a range of hills composed of Devonian andesitic lavas, tuffs and agglomerates running eastward from Stirling into north Fife, central Scotland. Their southern flank is bounded by a steep fault scarp - the Ochil Fault - to the south of which lie flat Carboniferous coal-bearing strata. Several quartz-dolerite dikes were intruded into the plane of the Ochil Fault in late Carboniferous times (Francis et al., 1970).

The western end of the Ochils has a long history of trial mines, mostly for copper, driven into barite veins along the steep south-facing fault scarp. The eastern extremity, in Fife, is famed for its abundance of fine agates. Alluvial gold and cinnabar are widespread, especially in the central area around Glendevon.

At Alva the silver occurred in a northeast-trending vein on the west bank (not the east bank as incorrectly stated by previous authors such as Francis et al., 1970; Dickie and Forster, 1974; Hall et al., 1982; and Parnell, 1988) of a small stream - the Silver Burn - in the Silver Glen, on the steep southern flank of the Ochils and about a kilometer east of Alva. The vein is hosted by an andesitic lava and is about 130 meters north of a quartz-dolerite intrusion along the Ochil Fault.

MINERALOGY

Virtually the only silver mineral present is the native metal. Electron microprobe investigations have detected minute grains of an unnamed Ag-Bi-selenide (Parnell, 1988). Associated primary metallic ores are massive and disseminated cobalt and nickel arsenides (mostly clinosafflorite and rammelsbergite, identified by X-ray diffraction and electron microprobe analysis) and copper sulfides (mostly chalcocite) in a gangue of dolomite, coarse tabular barite and calcite. These are currently the subject of research at the University of Edinburgh and Manchester Museum; full details will be published in due course. Oxidation in the dump has produced stains and efflorescences of erythrite, tyrolite, annabergite, malachite and, rarely, conichalcite and picropharmacolite. Of all these only the silver has been found as specimens of interest to the collector, although the clinosafflorite, being an extremely rare mineral, also merits a description.

Clinosafflorite (Co,Fe,Ni)[As.sub.2]

The principal primary cobalt arsenide mineral present in the silver mine dump is clinosafflorite. This rare, monoclinic polymorph of safflorite (Co[As.sub.2]) is known from only a few other locations worldwide: the Nord mine, Sweden (Burke and Zakrzewski, 1983), several deposits in the Bou Azzer region, Morocco (Vinogradova et al., 1980) and the type locality, Cobalt, Ontario (Radcliffe and Berry, 1971). At Alva it occurs disseminated and massive in dolomite/barite gangue as irregular, metallic gray masses superficially altered to erythrite and sometimes exhibiting coloform and stellate habits. It commonly encrusts silver and sometimes shows evidence of fracturing and shattering, presumably due to movement along the fault.

Silver Ag

The silver is almost invariably well-crystallized, nearly always as dendrites, typically 2 to 5 mm long but in some cases up to 3 cm. An 18th-century specimen in the Hunterian Museum, Glasgow (specimen M953), has dendrites to 4 cm. The dendrites branch at 90 [degrees] and are commonly terminated by four-sided pyramids, but also rarely by flat squares or rectangles. Cubes to 1 mm and branching mossy forms also occur occasionally but only one tiny specimen of filiform silver like that from the famous Kongsberg mines has been found, with curved wires to 0.75 mm long and 0.15 mm thick over an area of about 3 square millimeters.

The matrix is usually dolomite, sometimes barite, rarely calcite. clinosafflorite commonly encrusts the silver. A peculiar feature of some specimens is the presence of dendritic patterns in matrix occurring parallel to or in alignment with silver dendrites and occasionally containing corroded relict silver. These represent areas where the silver has been dissolved and replaced by matrix. Energy-dispersive analysis of these detects only Co, As, Fe and Ca.

The accompanying photographs have been selected to show the range of habits that occur. Matrix has been removed with acid to reveal the silver. (Orthophosphoric acid is preferred for this purpose because stronger acids liberate hydrogen sulfide which blackens the silver.) When found, specimens are normally erythrite-stained with only the shiny tips of silver dendrites visible.

CURRENT SITUATION

Recent excavations in the mine dump have yielded scores of small (and a few large, up to 100 grams) specimens of silver-beating ore from a small area which appears to have escaped being reworked by the cobalt miners. These excavations culminated in a four-day dig in May 1994 by the Royal Museum of Scotland using a mechanical digger and washing in a sluice the richest portions of the dump. During this time around 20 to 30 specimens of silver were recovered.

Specimens nowadays are virtually unobtainable, the small silver-bearing part of the dump having been systematically excavated and exhausted. The site is now owned by the Woodland Trust and the grounds of Alva House are now the Ochil Hills Woodland Park. A footpath leads from the park to the Silver Glen. Little do walkers on this path suspect, as they cross the stream, that just a few meters under their feet once lay the richest bonanza of native silver ever found in Britain.

ACKNOWLEDGMENTS

The author is greatly indebted to the following without whom this article would not have been possible: The Forestry Commission and the Woodland Trust, former and current owners respectively of the mine site, for permission to collect samples; staff at the National Library of Scotland, Edinburgh, and the Scottish Records Office and Public Records Office, in Edinburgh and Kew respectively, for assistance with historical research; Mike Rothwell, Unilever Research, for energy dispersive analyses; A. Livingstone, Royal Museum of Scotland, Peder Aspen, University of Edinburgh, and Amanda Edwards, Manchester University for mineralogical identifications; George Ryback, Sittingbourne for help with the map; Dave Green, Manchester Museum and Ken MacKay, Cambusbarron, for photography; and Dave Green for helpful comments during the preparation of the manuscript.

* A "stone" was equivalent to 14 pounds.

REFERENCES

[Abbreviations: f. = folio; MSS = Manuscripts; NLS = National Library of Scotland; PRO = Public Records Office, Kew; SRO = Scottish Records Office.]

ALLARDYCE, A. (1888) Scotland and Scotsmen in the Eighteenth Century, part I, p. 100-110, part II, p. 110-111. Wm. Blackwood and Sons, Edinburgh and London.

ANONYMOUS (1766) Wage receipt dated June 3. NLS, Erskine-Murray MSS 5099, f. 55.

BLACK, J. (1759) Letter dated January 17. NLS, Erskine-Murray MSS 5098, f. 49.

BRANDSHAGEN, J. (1717) Report dated April 29. PRO, T64/235.

BURKE, E. A. J., and ZAKRZEWSKI, M. A. (1983) A cobalt-bearing sulfide-arsenide assemblage from the Nord mine (Finnshytteberg), Sweden: a new occurrence of clinosafflorite. Canadian Mineralogist, 21, 129-136.

CRISP, N. (1761a) Letter dated November 1. NLS, Erskine-Murray MSS, 5098, f. 132.

CRISP, N. (1761b) Letter dated November 23. NLS, Erskine-Murray MSS, 5098, f. 138.

CRISP, N. (1762) Letter dated April 16. NLS, Erskine-Murray MSS, 5098, f. 152.

DICKIE, D. M., and FORSTER, C. W. (1974) Mines and Minerals of the Ochils. Clackmannanshire Field Studies Society.

DUNCAN, J. (1796) Parish of Alva. Statistical Accounts of Scotland, 9, 156-160.

ERSKINE, C. (1716a) Letter dated May 26. SRO, GD1/44/7, f. 9.

ERSKINE, C. (1716b) Letter dated June 18. SRO, GD 1/44/7, f. 12.

ERSKINE, C. (1716c) Letter dated July 8. SRO, GD1/44/7, f. 18.

FRANCIS, E. H., FORSYTH, I. H., READ, W. A., and ARMSTRONG, M. (1970) The geology of the Stirling district. Memoirs of the Geological Survey, Great Britain-Scotland, HMSO, Edinburgh.

HALL, I. H. S., GALLAGHER, M. J., SKILTON, B. R. H, and JOHNSON, C. E. (1982) Investigation of polymetallic mineralization in Lower Devonian volcanics near Alva, Central Scotland. British Geological Survey, Mineral Reconnaissance Programme Report no. 53.

HAMILTON, J. (1716) Affidavit dated July 3. NLS, Paul MSS, 5160, f. 5.

HYND, D., ed. (1981) The History of Alva and District from the Early Christian Period to 1900. Clackmannan District Libraries, p. 11.

LAUDERDALE, EARL OF, HALDANE, J., and DRUMMOND, W. (1716) Journal dated November 26. PRO, T1/201/96-99.

NEWTON, I. (1721) Notes written on a receipt for coach hire dated July 22. PRO, MINT 19/3/250.

PARNELL, J. (1988) Mercury and silver-bismuth selenides at Alva, Scotland. Mizx neralogical Magazine, 52, 719-720.

RADCLIFFE, D., and BERRY, L. G. (1971) Clinosafflorite: a monoclinic polymorph of safflorite. Canadian Mineralogist, 10, 877-881.

STEPHENSON, J. (1768) Letter dated June 5. NLS, Erskine-Murray MSS, 5099, f. 71-73.

VINOGRADOVA, R. A., KRUTOV, G. A., BOCHEK, L. I., GARANIN, V. K., EREMIN, N. I., KUDRYAVTSEVA, G. P., and SOSHKINA, L. T. (1980) Diarsenides of cobalt, iron and nickel in ores of the Bou Azzer region of Morocco. Vestnik Moskovskogo Universiteta Geologiya (Moscow University Geology Bulletin), 35 (6), 79-88.
COPYRIGHT 1996 The Mineralogical, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1996 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Moreton, Stephen
Publication:The Mineralogical Record
Date:Nov 1, 1996
Words:4394
Previous Article:Rocks from Space: Meteorites and Meteorite Hunters.
Next Article:The Kruisrivier cobalt mine, Transvaal, South Africa.
Topics:

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters