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.