GOLD
1. PROPERTIES OF GOLD
Gold is a bright, shiny yellow metal, noteable for its great density – 19.3 times the weight of an equal volume of water; and valued for its extreme ductility, high resistance to corrosion, lustrous beauty, and for its scarcity.
Because it is the least chemically active of all metals, gold usually occurs in the free or uncombined state. It is sometimes found as nuggets, flakes or dust in gravel or sand along creeks and streams; these deposits are called placers.
More often today, gold is found in veins in bedrock called lodes. The Waverley gold was found in lodes.
2. GEOLOGY OF THE MEGUMA GROUP
The Waverly deposits belong to a formation of rocks called the Meguma group. The Meguma group is a 10 – 14 km thick folded complex of slates and greywackes. These rocks were deposited in an ancient proto Atlantic Ocean 450 – 500 m.y.a. as mud, sand and silt. Over millions of years these sediments metamorphosed into slate and greywacke (quartzite). The gold bearing veins associated with the Meguma group are composed of mineral called quartz. These veins often lie within the folds of the slates and greywacke.
Most veins are parallel to the beds, although cross cutting veins have been observed and mined. The veins can vary in length from 100’s to 1000’s of meters and can go as deep as 200 – 300 meters. The veins vary in color from white crystalline to a blue-grey greasy appearance.
3. HYPOTHESIS ON FORMATION
There are two principles that categorize the hypotheses of formation.
(A) Syngenetic hypothesis – the sediment and the gold had simultaneous deposition. The gold was settling to the bottom of the ancient ocean with the other sediment. As the sediment lithified (hardened) over millions of years the gold was entrapped within the strata (layers) of rock.
(B) Epigenetic hypothesis – the gold bearing veins were formed by the injection of gold rich quartz solutions into fractures in the Meguma group. The sediments were laid down, then lithified and folded. The intrusion of the molten quartz with super heated water occurred as the fractures formed in the already existing rock.
Both hypotheses involve deposition, lithification and deformation (folding). It is the timing of the formation of the gold bearing veins that distinguish the two hypotheses.
4. 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% of the gold was left behind in the tailings (associated non-gold bearing rock). The yield of gold from crushed ore depended greatly upon the size and visibility of the gold. When quartz ore was brought to the surface, water was splashed on it and only if visible gold showed was the rock sent to the crusher!!
Three methods of extraction: gravity separation, amalgamation and cyanidization.
(a) Gravity separation – this is the physical separation of the gold from the country rock or impurities based on weight differences. Water is added to crushed ore in a gold pan, a sluice box or a jig. The slurry (crushed ore) is manipulated in a manner (swirled or shook) that causes the heavier gold to collect on the bottom of the apparatus.
(b) Amalgamation – this involves the dissolving of gold in mercury. Mercury is added to crushed ore and any free gold (physically separate from impurities) is absorbed by the mercury. The gold-mercury mixture is first placed in a leather bag and squeezed to remove the excess mercury. The mixture called amalgam is then heated in a closed system to evaporate the mercury. The gold is then melted into a saleable form.
(c) Cyanidization – in this method, crushed ore is dissolved in a mixture of lime and cyanide. The unwanted solids are removed by filtering. Zinc dust is then added to the liquid causing the gold to settle out of solution. Cyanidization replaced amalgamation in the 1880’s as a more efficient means of extraction.
Cyanidization is the most widely used gold recovery technique used in Canada and is the basis of modern heap leaching processes. Leaching solutions are poured over piles of crushed ore, and then collected and refined to extract dissolved gold.
5. GOLD MINING IN WAVERLEY, NOVA SCOTIA
Three gold rushes in Nova Scotia
1. 1860 – 1867 600,000 ounces
(2/3 of the gold mined in N. S. was taken by 1900))
2. 1895 – 1907 240,000 ounces
3. 1932 – 1942 158,000 ounces
(Gold rush #4 1972 ?)
Over 125 years, 1.2 million tray ounces mined.
There were 65 gold districts located in Nova Scotia.
From 1578 – 1857 there were many unofficial discoveries of gold in Nova Scotia, but it wasn’t until 1860 that a farmer by the name of John Gerrish found gold in a quartz boulder at Mooseland (Tangier) that the first gold rush of Nova Scotia was initiated.
After the declaration of the Mooseland gold district in April 1861, other discoveries along the Eastern Shore and elsewhere were quick to follow. Tangier, Lawrencetown, Sherbrooke, The Ovens, Gold River and Waverly to name a few. Buildings were erected overnight and miners and their families moved into the new settlements.
6. Waverley Gold Mining District
Of the total 1.2 million ounces of gold mined in Nova Scotia from 1892 – 1976 73,000 ounces were mined in Waverley.
There is some controversy over who first struck it rich in Waverley; Cornelius Blair (Charles P. Allen’s son-in-law), Henry Taylor or James Skerry. But it was Henry Taylor, who on August 23, 1861, first made a public announcement in Halifax of the gold in Waverly.
This prompted Joseph Howe, to drive to Waverley to observe the area for himself. He was quoted as saying “I visited the place and found that hundreds of dollars worth of gold has been taken out of loose quartz boulders lying about the surface of a hill some 50 acres in extent?”
Charles P. Allen owned 700 acres of land in the area directly opposite the Waverley Bridge and rented out plots of land ¾ acre in size for $160.00 annually to 30 – 40 representatives from different companies.
In 1862 the Nova Scotia government proclaimed Waverley as a gold district. Large scale gold mining at Waverley ended near the turn of the century after two notable gold rushes from 1862 – 1867 and from 1900 – 1903. It was briefly revived in 1935. Very small scale independent mining happened now and then at Waverley until 1962. Nowadays the gold is gone and nearly forgotten.