Gold in Nova Scotia
by Jennifer L. E. Bates
Nova Scotia Department of Natural Resources, Mineral Resources Branch, Information Series ME 13, 1987.
Table of Contents
Introduction
The History of Gold Mining
Mining and Extraction of Gold
Early Mining Methods
Extraction Methods
Occurrence and Distribution of Gold
Geology of the Meguma Group
Meguma Group Quartz Veins and the Hypotheses of Formation
Quartz Veins
Hypotheses for Formation
Present Exploration and Future Trends
References
Additional Reading
Glossary
Appendix - Do-It-Yourself
Acknowledgments
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Introduction
In recent years, Nova Scotia has witnessed a resurgence in gold exploration. The public has responded with a request for a general information document on gold in Nova Scotia. This booklet has been written as an answer to this request. In contains brief descriptions of the history of gold mining in Nova Scotia, mining methods, occurrences and distribution of gold in the Province, production figures, and the geology and theories of ore formation of the gold deposits. a glossary of terms that may be unfamiliar to the reader is included in the booklet. Anyone wishing to obtain additional information on gold in Nova Scotia is encouraged to do so and may begin by referring to the Do-It-Yourself section at the end of the booklet.
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The History of Gold Mining
There are probably not many of use who have firsthand accounts of the gold rushes in Nova Scotia, but maybe we can remember stories told by a grandparent, an older relative or perhaps an old prospector. The gold rushes have played a significant role in the history of many towns and villages in the Province and, for many Nova Scotians, gold mining is a distinct part of their heritage.
Gold may have been sighted as early as 1578 when the explorer Sir Humphrey Gilbert was given a patent to search for gold and silver in the New World. As well, French settlers may have found gild, as indicated by the village names of Bras d'Or, Cape d'Or or Jeddore (Jet d'Or). However, no ancient workings have been discovered to prove such suspicions.
Gold sightings were not referred to again until the 1830s. Labourers building roads in Nova Scotia spoke of a "bright yellow metal in the stone." These first 'discoverers' did not realize their good fortune and actually whittled the gold with their knives during mealtimes! An unidentified captain of the Royal Welsh Fusiliers was said to have panned gold at Gold River in 1840. In 1849, W. Brooks,1a farmer from Lawrencetown, claimed to have found gold in quartz while repairing a dam on his land but his farther gold him to "drop his nonsense, go on with his work and pitch the rubbish away".2Eleven years later, gold was discovered by Brooks who had been encouraged by recent discoveries at Tangiers. The area was declared the Lawrencetown gold district!
In 1857, unofficial discoveries were made by Richard Smith of Maitland who obtained gold from a river in the Musquodoboit settlement and by John Campbell of Dartmouth who 'assayed' the sands at Fort Clarence in Halifax Harbour (where the oil refinery stands today) and obtained a 'good show' of gold .
The first authenticated discovery of gold in quartz was made in 1858 by Captain L'Estrange at Mooseland.1However, he received no encouragement to continue his efforts. Within two years a farmer from Musquodoboit, John Gerrish Pulsiver, began a search in the same area of Mooseland. One the last Thursday or Friday in May 1860, Pulsiver found gold in a quartz boulder and thus initiated the first gold rush in Nova Scotia.
After the declaration of the Mooseland gold district in April 1861, other discoveries along the Eastern Shore were quick to follow in the next half year - Tangier, Lawrencetown, The Ovens, Wine Harbour, Sherbrooke (Goldenville), Waverley, Country Harbour, Isaacs Harbour, Isaacs Harbour and Gold River. Buildings were erected 'overnight' and the miners and their families moved into the new settlements.
Most the early claims were staked by people with no knowledge of geology or mining. Those who staked claims in the winter hoped there would be gold nuggets for the picking when the snow had melted. Reality did not meet with their expectations and initial claims were dropped only to be staked by companies that were able, financially and technically, to undertake the work.
John Campbell, who had observed gold on the shores of Fort Clarence, ventured to Lunenburg and worked the beach sands at The Ovens with William Cunard, Esq. of steamship line fame.3Campbell believed the sands of Sable Island contained gold but when he applied for a license, the government offered very confining terms and he was forced to abandon any idea of panning the sands.
Gold production increased as a result of the expansion in exploration to new areas located south and west of the Eastern Shore. The highest yield of gold was 27,538 ounces (780 702 g) in 1867. However, poor mining methods, bad management and incompetency led to the decline in production in the early 1870s. By 1874, the output had dwindled to 9,140 ounces (250 119 g).
The miners had no means of predicting where additional ore zones could be found and production decreased once the most accessible and richest zones had been worked. get-rich-quick schemes had been the order of the day, money earned had been squandered and no funds remained for further exploration.
However, companies that were unable to raise the capital for gold ventures would lease their property for a return payable in gold mined to individuals called tributers. This working relationship between company and the individual tributer was called the tribute system. Although profitable to the single operator, the gold yield remained low.
The second gold rush extended from 1896 to 1903 with the highest yield of 31,113 ounces (882 054 g) in 1898. The introduction of dynamite for blasting, the use of cyanide in the concentration process, and more efficient machinery and mills permitted bodies of lower grade ore to worked. Much attention was given to improving the concentration process and the treatment of tailings, with the intention of increasing the gold yield. Unlike the first rush which was a time of frenzy and speculation, this renewed quest for gold was a time of calm, organized exploration.4
In the late 1890s, the Klondike gold rush, in combination with the opening of the mining camps in Ontario, conjured dreams of 'easy gold ' in the minds of the workers. The result was a movement to the west, with a corresponding decline in gold production in Nova Scotia.
The demand for arsenic in the 1920s initiated exploration for arsenopyrite - a mineral associated with the Nova Scotia gold deposits5 - and thus renewed the search for gold. This fact, along with cheap energy costs and an increase in the price of gold (US$20.67 to US$34 per ounce), created an impetus for Nova Scotia's third gold rush. The rush spanned ten years (1932-1942) and 158,000 ounces (4 479 300 g) of gold was produced.
Although classified as a base metal operation and therefore termed a god producer rather than a gold district, the Stirling Mine on Cape Breton Island produced between 1952 and 1956 the majority of the gold (at least 95%) from Nova Scotia gold mines. The deposit was discovered about 1895, diamond-drilled from 1916 to 1918, developed during the 1920s and 1930s, recorded an initial gold production of 3,401 ounces (96 418 g) from 1936 to 1938, and produced 13,280 ounces (376 488 g) of gold in total from 1952 to 1956.
What may, in time, be considered the fourth gold rush began in 1972. The resurgence of gold exploration was encouraged by the rise in the price of gold (to ~US$820 per ounce!) in the early 1980s. a number of companies staked claim with the idea of working the tailings or old underground mine sites, or prospecting for new leads. Today, the search for gold continues and the future outlook for Nova Scotia gold is optimistic.
Photos: (not presently available)
Miners outfitted for underground work in the mine at the Waverley gold district, Halifax County (ca. 1915).
John Gerrish Pulsiver.
The discovery of gold in quartz at Tangier (Mooseland), Halifax County, Nova Scotia, May 1860.
From a posed studio photo by W. Chase.
Courtesy of the Public Archives of Nova Scotia.
Underground at the workings of the Dominion gold mines, Waverley, Halifax County.
Share certificate issued from the Caribou Gold Mining Company for Caribou Mines in Halifax County on September 14, 1894.
Interior of the milling house of the Lacey gold mine at Gold River gold district in Lunenburg County, Nova Scotia, 1934. The conveyor (top) brings rock to the surface where it is crushed and then treated in the amalgamation tray with mercury to separate the gold (foreground).
Native Waverley tributers (George, Lawrence and Lewis Sailer) mining at Laidlaws, Waverley in the spring of 1933.
Mining facilities at the Montague gold district.
Mining operations at the Moose River gold district.
Figure: (not presently available)
The quantity of gold produced in Nova Scotia from 1862 to present day. The suspected caused for particular peaks and troughs are indicated on the graph.
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Mining and Extraction of Gold
Early Mining Methods
The early findings of gold were in quartz boulders and quartz veins. The first workings were confined to excavation of surface quartz veins and trenching.
Extraction of gold involved the physical separation of the quartz from the surrounding slates and greywackes, and crushing of the quartz to liberate the gold. Picks, shovels, and muscle were the only tools.
The first underground gold mine was established at Tangier in 1860. The quartz ore was brought to the surface and crushed in an arrastra, which operated on the principle of grinding the quartz with stones and concentrating the gold with mercury.
The use of arrastras gave way to the use of more efficient crushers and stamp mills. The stamp mill consisted of a number of vertically placed iron or steel rods that were lifted 10 to 18 inches (25 to 45 centimetres) and dropped, by mechanical means, on the quartz at a speed of 50 to 80 drops per minute. One stamp was able to crush one ton of quartz in 24 hours.6Stamp mills usually were set up in batteries of three to five stamps. Crushing capacity could be increased by adding more batteries.
Another early apparatus was the Chilean mill. Massive wheels of granite revolved, on edge, in an iron pan crushing the quartz ore to a gritty, watery paste. This type of mill can be seen today at The Ovens Park in Lunenburg County.
The cost of power was high in the 1800s and it probably retarded the mining development. Cordwood or coal was used in highly wasteful steam plants. In some districts, waterwheels were utilized but the amount of energy produced was small.7
Photos: (not presently available)
Photo of front page of "the Gold Gazette", July 26, 1862. Courtesy of the Public Archives of Nova Scotia
Gold washing at the Ovens, Lunenburg County.
Drawings: (not presently available)
An arrastre: the movement of a large stone attached to a wooden arm crushes the ore.
A five-stamp mill.
The Chilean mill: wheels of granite move over the crushed ore liberating the gold .
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Extraction Methods
The gold extraction methods used in the early workings were wasteful. At the time, it was believed that in a few districts at least 30 per cent of the gold was left behind in the tailings.4The yield of gold from crushed ore depended greatly upon the size and visibility of the gold. When the quartz ore was brought to the surface, water was splashed on it and only if visible gold showed was the rock sent to the crushers! Undoubtedly, significant quantities of gold were sent to the tailing piles. Only the larger pieces of gold were extracted and much of the fine gold was lost in the crushing or concentrating process.4Consequently, the tributers who worked the tailing in later years often found their efforts were rewarded.
There are three methods of extracting gold from crushed ore which have been in use since the early gold rushes: gravity separation, amalgamation and cyanidization.8Chlorination and ore roasting were attempted in early mining days but proved to be less efficient and therefore were not continued.
Gravity separation is the physical separation, based on weight differences, of gold from its impurities. Water is added to be crushed ore in a gold pan, a sluice box or a jig. The slurry is manipulated in a matter (i.e. swirled or shook) that causes the heavier gold to collect on the bottom surface of the apparatus.
Amalgamation involves the 'dissolving' of gold in mercury. Mercury is added to the crushed ore and the free gold (gold physically separate from the impurities) is absorbed by the mercury. In one method, the gold -mercury mixture (amalgam) is first placed in a leather bag which is squeezed to remove the excess mercury. The amalgam is then heated in a closed system to evaporate the mercury. Lastly, the gold is melted into a saleable form.
In the 1880s, cyanidization replaced amalgamation as a more efficient means of extraction. In this method, crushed ore is dissolved in a mixture of lime and cyanide. The unwanted solids are removed by filtering. Zinc dust is added to the liquid, which causes gold to settle out of solution. Cyanidization is the most widely used gold recovery technique used in Canada and is the basis of the modern heap leaching process. Leaching solutions are poured over piles of crushed ore, and then collected and refined to extract the dissolved gold .
Figure: (not presently available)
The extraction process of cyanidization.
Drawings: (not presently available)
Gold panning: probably the first of the early mining methods.
Cradle or rocker box: the function is very much like that of the sluice however it uses much less water.
Figures: (not presently available)
Side and top views of a riffle section of a sluice (upper) and a close-up of the various styles of riffles (lower); a sluice is generally placed directly in the stream for greater ease when working the auriferous material.
The extraction of gold from unwanted material using the process of amalgamation and a closer look at the final steps of the mercury process of gold extraction where the amalgam is heated in a retort bringing about the separation of gold from mercury.
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Occurrence and Distribution of Gold
In Nova Scotia, gold occurs as vein (lode) deposits and occurrences, modern placers, paleoplacers and as disseminated gold in various rock types.
The vein or lode deposits are predominantly associated with the Meguma Group slates and greywackes of the southern mainland although occurrences do exist in Cape Breton Island and the Cobequid Highlands. Virtually all of the established gold districts are vein deposits in the Meguma Group rocks.
Modern placer gold accumulates in beach or river sediment as a result of the erosion of gold -bearing rocks and accumulation of gold due to wave action or current motion. These deposits were among the first to be worked in the early gold mining days as they were accessible and easy to work. Modern placers are associated with beaches and rivers at numerous locations within the Province.
Paleoplacers are placers that were formed millions of years ago and the once unconsolidated sediments are now solid rocks. The paleoplacers, found on the southern mainland, occur in Horton Group conglomerates of Devono-Carboniferous age. Erosion of paleoplacers and redistribution of the gold by modern rivers and oceans may result in the formation of reworked placers.
Gold as disseminated particles is present in various types of igneous, sedimentary and metamorphic rocks. Sightings have been noted in slates and greywackes of the Meguma Group, sedimentary rocks of the Horton Group, granites south of the Cobequid -Chedabucto Fault, volcanic rocks of the Cobequid Highlands, and metamorphic and igneous rocks of Cape Breton Island.
Photo: (not presently available)
A mining operation at Gold River.
Figures: (not presently available)
Two sketches showing the environments in which gold may be found.
Areas where gold particles may accumulate:
boulders, bedrock outcrops and gravel bars at the bends in streams;
the lee side of boulders and widened areas downstream of rapids where the velocity of the stream has decreased.
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Geology of the Meguma Group
Virtually all the declared gold districts are vein deposits in the Meguma Group rocks of the southern mainland. a brief summary of the geological history of the rocks and the hypotheses concerning the formation of the quartz veins that host the gold will be given in this and the following sections.
The Meguma Group is a six to nine mile (10 to 14 kilometre) thick, folded complex of slates and grey wackes. The greywackes were originally sands deposited over 500 million years ago as turbidites (underwater landslides) on an ancient continental rise. The slates were clays deposited predominantly on the ancient continental slope but as far offshore as the deep sea.9The gold-bearing veins associated with the Meguma Group are composed of quartz. a number of theories exist concerning the origin of the quartz and the gold.
The ancient marine environment where the clays and sands were deposited was positioned off the coast of northwestern Africa. It was similar to the present-day Atlantic margin of North America. Due to continental drift, Africa and North America 'collided' approximately 400 million years ago along the line of the Cobequid - Chedabucto Fault. In a general sense, this event resulted in the formation of the Appalachian Mountain range and a new land mass called Pangea.
More specifically, the clays and sands of the Meguma Group were compressed between the colliding continents into tight folds (anticlines and synclines), and metamorphosed to slates and greywackes. Approximately 360 to 370 million years ago granite magmas, produced by the high pressure melting of the metamorphic sediments in the roots of the Appalachian Mountains, intruded the folded rock deep below the Earth's surface. The magmas slowly solidified and, after millions of years of erosion of the Appalachian Mountains, are now exposed on the surface. The South Mountain and Musquodoboit Batholiths are two major granitic bodies formed in this manner.
Erosion of the land mass resulted in the accumulation of thick sediment sequences, as the Horton and Windsor Group rocks. The basal conglomerates, that host the paleoplacers, were formed at this time.
During the Triassic Age (160 million years later) Pangea rifted apart and the Atlantic Ocean began to form. When the land mass split, the Meguma Group rocks separated from the African continent, remained attached to North America along the Cobequid - Chedabucto Fault and formed the southern half of Nova Scotia. In the Appalachian Mountain range, the Meguma Group is unique as it is "the only outcropping remnant of Africa left in North America."10
The final event in the geological history was the deposition of glacial till during the Pleistocene glaciation. The blanket of till, which covers much of the bedrock, was produced by the grinding action of ice as it moved over the surface of the rocks. The ice sheets retreated from this region approximately 10,000 years ago, leaving behind the topography observed today in Nova Scotia.
Photos: (not presently available)
A miner cleaning muck from a recent blast in a cross-cut at the Beaver Dam deposit developed by Seabright Resources Incorporated.
The anticlinal fold structure often observed in the gold bearing rocks of the Meguma Group.
Figure: (not presently available)
The ancient supercontinent of Pangea; note the location of Nova Scotia.
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Meguma Group Quartz Veins and the Hypotheses of Formation
Quartz Veins
Lode gold is found in quartz veins that are largely associated with the complicated fold structures of the Meguma Group rocks. The gold -bearing (auriferous) veins most often lie within the slate beds. These beds are comparable to the original sediment layers, with no one particular bed containing all the productive veins. Most veins are parallel to the beds, although cross-cutting veins in the slates and greywackes have been observed and mined. The veins that run parallel to the beds are often folded or corrugated. The vein orientation, which resembles a series of casks laid side by side and end to end, was called "barrel quartz" - a term first used by the miners at Waverley.
The length of the veins can be thousands of feet (100s to 1000s of metres) and the vertical extension below the Earth's surface as much as 700 feet (213 metres). The thickness varies from one inch to 15 feet (2.5 centimetres to 5 metres). The colour and texture of the quartz veins varies from a white crystalline to a blue-grey greasy appearance. Historically, the latter type of quartz was the most productive.
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Hypotheses of Formation
Hypotheses on the formation of the veins and the source of the gold date back to the early mining days of the 1860s. There are two principles that categorize the hypotheses.
The first principle is based on the simultaneous deposition of sediment and gold (i.e. syngenetic hypotheses). While the clays and sands were settling to the bottom of the ancient sea, gold particles were doing so at the same time. With further deposition of the sediments, the gold particles were trapped. Over the millions of years to follow, the sediments were compacted, lithified (hardened) and turned to rock. Today the entrapped gold is contained within the strata (layers) of the rock. Depending upon the relative quantity of gold to clay, sand and quartz at the time of deposition, a layer of gold or disseminated gold (individual particles) was formed in the rock. According to this principle, the gold veins formed parallel to the sediment layers (i.e. concordant veins). Subsequent deformation folded and fractured the host rock slates and greywackes as well as the auriferous quartz veins.
The second principle involves formation of veins by the injection of gold -rich quartz solutions into fractures in the Meguma Group slates and greywackes (i.e. epigenetic hypotheses). The clay and sands were deposited in layers on the sea floor, lithified to form slates and greywackes, and these rocks folded, fractured and faulted. It was during these deformation events that openings, cooled and solidified to form auriferous quartz veins. Since the fractures or openings developed with no one preferred orientation with respect to the slates and greywackes, crosscutting (i.e. discordant) as well as parallel veins formed.
In summary, all geological events (i.e. deposition of sediments, lithification and deformation) did occur. However, it is the timing of the formation of the gold -bearing quartz veins that distinguishes the syngenetic and epigenetic hypotheses.
Photos: (not presently available)
Deformed quartz vein cutting Meguma Group Metasediments. This is a typical auriferous quartz vein observed in many of the gold deposits. The gold is generally found near the margins of the vein.
A quartz vein at the Fifteen Mile Brook gold district; note the intense folding of the vein.
Table: Troy Ounces of Gold Produced
Figure: (not presently available)
Simplified geological map of Nova Scotia depicting the basic geological units and the locations of the gold districts or producers; note that many of the gold districts coincide with the anticlinal fold axes of the Meguma Group rocks.
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Present Exploration and Future Trends
With the high price of gold in recent years, the investment in gold exploration in Nova Scotia has escalated. Since 1979 exploration expenditures have increased steadily. With respect to the other commodities, gold accounted for 85% of the total exploration dollars spent in 1987 - a substantial increase over the previous years.11
Current exploration programs for gold are not confined by the traditional theories or methods of exploration and mining. New theories, developed from recent studies on the origin of gold, have influenced exploration. Exploration programs are no longer restricted to the quartz veins of the Meguma Group rocks. Nowadays, programs have expanded to include not only the host rock slates and greywackes but also glacial tills, granitic rocks, and the rock units of the Cobequid Highlands and Cape Breton Island.
Feasibility studies have been done on the extraction of gold by heap leaching from the tailings and concentrates of old workings, and on the reopening of the old underground mines. At this time, gold properties at Forest Hill and Beaver Dam are in the final stages of development and nearing the production stage, with the Tangier property not far behind. Cochrane Hill, Harrigan Cove and Goldenville may be considered advanced development properties, while Fifteen Mile Stream, Mooseland, Moose River, Leipsigate and Molega are in the advanced exploration stage.
Dredging offshore sediments for gold recovery has also been investigated. Gold in glacial tills is of interest to geologists, as it may indicate if gold exists in the underlying bedrock. Lake, stream and rock geochemistry, geophysical surveys and remote sensing techniques - none of which existed at the time of the initial gold discoveries - aid in the detection and delineation of gold occurrences.
Today, gold exploration is taking a new direction. The gold discovery potential has never been better. Geological research, modern technology and the high market price of gold all point confidently to a bright future for Nova Scotia gold .
Photos: (not presently available)
A mining vehicle transporting some of the several dozen miners employed in the underground workings of the Beaver Dam deposit. The ventilation system is seen to the left of the photo. The mine is operated by Seabright Resources Incorporated.
Shaft (background) which provides vertical access to the Forest Hill gold deposit operated by Seabright Resources Incorporated. Underground development presently goes to the 200 m level.
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