Gold in Tasmania

The first payable gold discovery in Tasmania was made at Tullochgorum, near Fingal in the State's east, in February 1852. The find attracted about 200 men to the area, but it did not live up to expectations and was soon abandoned.

On the west coast initial searches for gold yielded very little. Several small deposits were found near Mt Arrowsmith, in the Forth River now under Lake Cethana, and outwards towards Lake Macquarie. It was not until 1883 that it was found in sufficient quantities (in a discovery which became known as the Iron Blow), to lure Prospectors away from the gold rushes of mainland Australia and New Zealand. The subsequent activity was instrumental in the development and growth of the West.

To encourage the Prospectors, the Tasmanian Government offered rewards for the discovery of a goldfield. The maximum available reward was 5000 pounds. In 1881 a reward of three thousand pounds was given to Samuel Richards when he discovered gold on Specimen Hill near Nine Mile Springs. The Lefroy Goldfield 12 km east of George Town became the first profitable goldfield.

In the late 1870s several small goldfields in the northwest were worked by Chinese diggers. Areas yielding small quantities of gold were on the Hellyer, Cam and Inglis Rivers, and at Doctors Rock, a landmark between Somerset and Wynyard.

Traces of gold led prospectors to the Pieman River, but this area was difficult to get to on foot and even more treacherous by boat. The only landing places for big boats on the West Coast, Macquarie Harbour and the Pieman River were dangerous to enter and its bad reputation had many captains unwilling to enter. In 1867 alone three schooners, the Rose Ann, the Dolphin and the Moyne were lost at the entrance to the river.

The Linda goldfields near Queenstown were worked from 1883 until about 1890. Gold was recovered from three main creeks - Cooneys Creek, White Creek and Henrys Creek. The Iron Blow, the massive iron outcrop proved to also contain gold. The ore contained lots of iron and sulphur, a small percentage of copper, gold and silver. In 1888, the Mt Lyell Gold Mining Company was formed in Launceston to treat the ore and recover the gold. The method used was not efficient and most of the gold was lost during the treatment, causing the company to work at a loss. In 1893 the company was taken over by the Mt Lyell Mining and Railway Company, which mined for copper. This company became one of the oldest mining companies in Australia.

Other areas south of Queenstown where alluvial gold was found came from the creeks flowing from Mt Strahan to the Garfield River; Flanigans Creek, named after the man who first found the gold; on the slopes of Mt Darwin and in the area between Mt Jukes and Mt Strahan. In 1902 a 6.5 ounce nugget was found in the area of Mt Darwin.

There were several mines in the area but most proved unprofitable. The Princess Gold mine was the only mine that recovered enough gold to return dividends to the shareholders. The Macquarie Gold Mine, between Strahan and Mt Lyell, The Madam Howard Gold Mine, at Howards Plain, The Woody Hill Gold Mine near Rinadeena and the Harris' Reward Gold Mine near the junction of Newell Creek with the King River all were unprofitable due to the method of recovering the gold. All these mines used a stamper battery for recovery, which achieved excellent recovery in stone with free gold, but was not good for ores that were complex and held the gold in chemical composition with other minerals, particularly sulphides such as pyrite and chalcopyrite.

Henty Gold Mine

The Henty gold mine, owned by the world's largest gold mining company, Barrick, and is located on the West Coast adjacent to the Southwest Conservation area. Henty lies within the mineral-rich Mt Read Volcanic Belt that hosts other base metal and gold deposits such as Rosebery and Mt Lyell. Gold production comes from a number of ore zones have produced more than 900,000 ounces of gold. Diamond Drilling programs over the past few years have revealed a number of zones and these will increase the mine life by several more years, and an aggressive drilling program to further prolong the life of the mine is underway.

Henty is a mine that almost never was. In the 1979s exploration in the area was for base metals, particularly copper which was highly sought. Some low grade ores were identified but the prognosis was poor for a profitable mine. In the 1980s, a period when gold was in high demand, an assay for gold on the core samples prior to relinquishing the tenement positively identified significant gold zones, which subsequently resulted in the Henty mine. Drilling and development began in the 1980s. The main zone called Zone 96 was identified in 1989. The first gold production was in 1996.

There are a number of different mining methods applied at Henty. These vary from cut and fill in the upper orebodies, uphole benching and transverse open stoping. Access to the mine is via a decline and an internal shaft.

Water used by the mine ultimately finds its way back to the Henty River, from where it was originally drawn and as a result must be clean. Mine water is treated through specially constructed wetlands which encourage solid settling and biological filtering before release.

Beaconsfield Gold Mine JV

The Beaconsfield gold mine has a long history. Gold was first discovered on the eastern slopes of Cabbage Tree Hill, west of the current township of Beaconsfield, in 1877. An underground mine, known as the Tasmania Gold Mine, operated between 1877 and 1914 and produced 854,570 ounces of gold before it closed. At that time it was one of the richest gold mining operations in Australia. Steam driven pumping technology utilising large Cornish beam pumps was installed to pump the huge amount of water out of the mine that consistently threatened the operations. However the pumps could not keep up with the water inflow, and this, plus the shortage of labour and materials at the onset of World War 1, high wage demands from the workforce, and poor metallurgical recovery, forced its closure. The mine was left to flood and this took 23 years.

During the 1980s and 1990s a drilling program was undertaken and a high grade reef, known as the Tasmania Reef, below the old workings, was confirmed. Redevelopment of the mine began in the early 1980s.

Recently a new drilling program commenced and the results indicate the mine will exist for at least several more years. The drilling is set to descend below the 1000 metre level. The Tasmania Reef is still regarded as the best in Australia and perhaps even the world.

In July 2004 the mine mined its millionth tonne of ore since it recommenced in 1985. The ore has yielded 450,000 ounces of gold worth $240 million. The mine produces approximately 4000 to 5000 tonnes of ore a week worth $1million to $1.5 million.

The plant is designed to treat 250,000 tonnes per annum of ore from the mine. Treatment consists of crushing, grinding, gravity concentration, sulphide flotation, bacterial oxidation, neutralization, cyanide leaching, Merrill Crowe precipitation, detoxification and tailings disposal. Gravity concentration recovers approximately 50% of the gold with a combined gravity and flotation recovery of about 94%.

Facts about Gold

• Is the only yellow metal
• Is named from the Old English word for yellow - Geolu
• Has the chemical symbol Au, from the Latin word for gold - Aurum
• Is the only metal that forms no oxide film on its surface in air at ordinary temperatures
• Is so malleable that gold leaf can be rolled so thin that light will pass through it
• Is an excellent conductor of heat and electricity
• Is highly resistance to attack by acids and will not dissolve in any of the common acids
• Will dissolve in alkaline Cyanide solutions
• Has a relative density of 19.32
• Has its purity expressed in carats - pure gold is 24C. The amount of gold in an alloyed product (caratage) is represented as a proportion of the pure gold. For example a nine carat ring contains 9/24 fine gold and 11/24 alloy by weight.
• Is mixed with other metals to produce alloys of different colours. Yellow, green and red golds are alloyed with copper and silver; white gold is alloyed with silver, palladium, nickel and copper
• Is 19.3 times heavier than water.
• There are two deposit types of gold - primary formed from hydrothermal fluids, and secondary produced by weathering and erosion of the primary deposit (alluvial)
• Most gold mined today in Australia cannot be seen in rock as it is very fine grained.
• About two-thirds of Australia's resources occur in Western Australia, with the remained in all other States and the Northern Territory and most are mined as open cut. In Tasmanian Henty and Beaconsfield mines are underground.
• The largest nugget ever found was in Victoria in 1869. It weighed 2,284 ounces or 69.9kg.
• Australia had its first gold rush in 1851 in Bathurst NSW, followed by Bendigo and Ballarat in Victoria.
• The main uses for gold are jewellery, dentistry, adornments, art and circuitry in electronic equipment.
• Gold was produced in Tasmania in 2003/04 from the Beaconsfield Gold Mine, Henty Gold Mine, and from the Rosebery and Mt Lyell polymetallic sulphide mines. More than 7,000 kg was produced in the form of concentrates and/or dore.

Reference: ITAM Gold produced by the Minerals Council of Australia

More information can be found at the Minerals Council and Chambers in all States and Territories.