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Mount Boppy Gold Mine was a gold mine at Canbelego, New South Wales, Australia. The original Mount Boppy Gold Mine operated from 1901 to 1922. It was, at the time, regarded as being the largest gold producer in New South Wales.
The gold-bearing deposit that became the Mount Boppy Gold Mine was discovered, in September 1896. The discoverer of the gold-bearing lode, a prospector, Michael Delaney O'Grady, lived near the Boppy Mount railway station, on the 
The new owners sank four shafts, and identified a huge gold-bearing lode, over 1,000 feet long to a depth of at least 200 feet; later mining would reach 300 feet deep, in 1902, 400 feet in 1904, and 800 feet, in 1911. The gold-bearing 
The mining village of Canbelego grew to the east of the mine's site. In 1905, the population had been around 1,500, with around 300 of these being employees of the mine. Between 1907 and 1917, the population was around 2,000.
For its time, the Mount Boppy Gold Mine was a sophisticated and well run operation, with its own assaying laboratory, and was an early adopter of the cyanide process. Below 240 feet, the lode transitioned from an oxide zone to a sulphide zone. The surface plant needed to be capable of treating both kinds of ore, especially as the mining went deeper. The company was able to reuse some equipment obtained from other mines. The company's huge 60-head stamper battery was divided so that the oxide zone ore was pulverised by 20-heads and the sulpide zone ore by the remaining 40-heads.
Water was precious in the semi-arid environment, with enormous amounts being needed for the processing operations. The mine had a 13 million gallon dam, condensed the exhaust steam from its steam engines for return to the boilers, and distilled brackish mine water. In the early 1920s, the area was subject to a long drought, which affected mining operations at the Mt Boppy mine.
The original Mount Boppy Gold Mine operated from 1901 to 1922. It was, at the time, regarded as being the largest gold producer in New South Wales. Over that period, the mine produced 13.5 tons (433,000 ounces) of gold. By the end of 1912, shareholders had received a return of 356% on their capital investment, rising to 500% over the entire 21 years of operation. After reef mining ceased in 1922, the old company reprocessed tailings, until finally closing the site and selling off equipment in 1923.Between 1929 and 1941, there was minor production of gold from remnant ore and attempts to process tailings. Around 500,000 tonnes of tailings—still containing an average of 3g of gold per tonne—were left on the surface. Starting in 1974, these tailings were reprocessed to recover more gold. Later mining operations included reprocessing of tailings sand that had been used to back fill the old underground workings. In recent years, the mine was reopened as an open-cut operation, but later placed under care and maintenance.
It is estimated that over its entire life, from
Mount Boppy Gold Mine - A Leader in its Day and More to Come, Kenneth George Mcqueen
{{Coord, 31, 33, 30.1, S, 146, 18, 57.8, E, display=title Gold mines in New South Wales
Cobar railway line
The Cobar railway line is a railway line in New South Wales, Australia. It branches west towards Cobar from the Main West Line at Nyngan. The Main West once continued northwest to Bourke but is now closed beyond Nyngan. However, copper concentra ...
. It was while walking back to his home, in September 1896, that he recognised the lode, where it was exposed in a watercourse. After dollying a sample of the rock, he found it was rich in gold.
The lode initially was worked by O'Grady and his partner Thomas Reid, under a mining claim known as 'Hidden Treasure'. In November 1897, the claim, and another 10 acres of mining claim land owned by other prospectors, were sold to the Anglo-Australian Exploration Company, for £1,000.
The new owners sank four shafts, and identified a huge gold-bearing lode, over 1,000 feet long to a depth of at least 200 feet; later mining would reach 300 feet deep, in 1902, 400 feet in 1904, and 800 feet, in 1911. The gold-bearing quartz reef
Quartz reef mining is a type of gold mining in "reefs" (veins) of quartz.
Quartz is one of the most common minerals in the earth's crust, and most quartz veins do not carry gold, but those that have gold are avidly hunted by prospectors.
In the s ...
varied in thickness, from 12 feet up to 37 feet. A 200 ton bulk sample, averaged slightly over 16 pennyweights (0.8 troy ounces
Troy weight is a system of units of mass that originated in 15th-century England, and is primarily used in the precious metals industry. The troy weight units are the grain, the pennyweight (24 grains), the troy ounce (20 pennyweights), and the ...
) to the ton. In 1900, the Mount Boppy Gold-Mining Company was formed, in London, to exploit the newly-proven, large, rich deposit. By July 1900, work on establishing the mine was well under way.
The mining village of Canbelego grew to the east of the mine's site. In 1905, the population had been around 1,500, with around 300 of these being employees of the mine. Between 1907 and 1917, the population was around 2,000.
For its time, the Mount Boppy Gold Mine was a sophisticated and well run operation, with its own assaying laboratory, and was an early adopter of the cyanide process. Below 240 feet, the lode transitioned from an oxide zone to a sulphide zone. The surface plant needed to be capable of treating both kinds of ore, especially as the mining went deeper. The company was able to reuse some equipment obtained from other mines. The company's huge 60-head stamper battery was divided so that the oxide zone ore was pulverised by 20-heads and the sulpide zone ore by the remaining 40-heads.
Water was precious in the semi-arid environment, with enormous amounts being needed for the processing operations. The mine had a 13 million gallon dam, condensed the exhaust steam from its steam engines for return to the boilers, and distilled brackish mine water. In the early 1920s, the area was subject to a long drought, which affected mining operations at the Mt Boppy mine.
The original Mount Boppy Gold Mine operated from 1901 to 1922. It was, at the time, regarded as being the largest gold producer in New South Wales. Over that period, the mine produced 13.5 tons (433,000 ounces) of gold. By the end of 1912, shareholders had received a return of 356% on their capital investment, rising to 500% over the entire 21 years of operation. After reef mining ceased in 1922, the old company reprocessed tailings, until finally closing the site and selling off equipment in 1923.Between 1929 and 1941, there was minor production of gold from remnant ore and attempts to process tailings. Around 500,000 tonnes of tailings—still containing an average of 3g of gold per tonne—were left on the surface. Starting in 1974, these tailings were reprocessed to recover more gold. Later mining operations included reprocessing of tailings sand that had been used to back fill the old underground workings. In recent years, the mine was reopened as an open-cut operation, but later placed under care and maintenance.
It is estimated that over its entire life, from hard-rock mining
Underground hard-rock mining refers to various underground mining techniques used to excavate "hard" minerals, usually those containing metals, such as ore containing gold, silver, iron, copper, zinc, nickel, tin, and lead. It also involves the ...
and tailings reprocessing, the mine has produced 500,000 ounces of gold. Only with the opening of the New Occidental mine at Wrightville
Wrightville was a mining village in the Orana region of New South Wales, Australia. Once it was a significant settlement, with its own municipal government, public school, convent school, post office, police station, four hotels, and railway ...
, near Cobar, in the 1930s, did the Mount Boppy mine lose its place as the most productive gold mine in New South Wales.
Paradoxically, it had been the company's decision not to exercise an option that it held over the Occidental Mine, in mid 1922, which had left the Mount Boppy Gold-Mining Company, despite its attempts to identify others, without suitable future gold-mining prospects.
In 2020, drilling revealed intersections of high-grade gold-bearing ore below the bottom of the existing pit. Gold was again being mined there in 2021, and that was expected to continue, until 2022, together with limited mine site rehabilitation.
References
External links
Mount Boppy Gold Mine - A Leader in its Day and More to Come, Kenneth George Mcqueen
{{Coord, 31, 33, 30.1, S, 146, 18, 57.8, E, display=title Gold mines in New South Wales