Citigold Corporation Limited is an ASX-listed company with gold and silver exploration and mining operations within the Charters Towers tenements in northern Queensland. Charters Towers is 100% owned by Citigold and the deposit represents one of the highest grade goldfields in Australia. The project is expected to enter into a development and ramp up phase which could lead to a notable increase in production.
LionGold Corp owns 15% of Citigold Corporation Limited, and is the company’s largest single shareholder.
The centre of the Charters Towers goldfield is about 1,000 kilometres north of Brisbane and 128 kilometres southwest of Townsville in Queensland, Australia.
Size & Prospects:
Tenements include 148 square kilometres Central goldfield with control of a surrounding exploration area of more than 1,000 square kilometres through 58 holdings:
- 47 Mining Leases spanning 24.4 square kilometres
- 5 Mineral Development Licences spanning 48.9 square kilometres
- 2 Exploration Permit Minerals Applications spanning 604.8 square kilometres
- 4 Exploration Permit Minerals spanning 875.6 square kilometres
The defined Resources generally extend at a depth of between 100 and 1,200 metres in over 80 major reefs typically 0.3 metres to 1.5 metres thick over a total strike length of about 5 kilometres. The gold is finely disseminated but is largely free milling. The Central area is an established mine site and contains some 6 million ounces of gold along about 4km of strike. The Imperial area includes the Warrior and Sons of Freedom reefs to the southeast of Charters Towers and contains about 4 million ounces of gold.
Standard Minproc style Carbon-in-Leach (CIL) gold processing plant with a design capacity of 340,000 tonnes per year.
Charters Towers has been mining and extracting gold intermittently from 1993, and continuously since 2007. Over 95,000 ounces of gold and 45,000 ounces of silver have been produced from 1997. Of this, from 2007, 57,000 ounces of gold and 30,000 ounces of silver were produced from the Imperial Mine reefs. The highest recent annual production was 15,888 ounces in FY2010 (June YE). Since 1997 until June 2011, total investment in Charters Towers was reported as A$179m. In 1999, Mineral Resources had been defined at 300,000 ounces from 2 metres tonnes of ore at 4.8 grams per tonne.
The Charters Tower goldfield was discovered in 1871 and produced some 6.6 million ounces of gold from 6 million tonnes of high-grade ore from 1872 to 1920. Up to 40 companies operated 206 mining leases covering 127 mines working 80 lines of reef and 95 mills, cyaniding and chlorination plants. The field produced over 200,000 ounces per year for 20 consecutive years. The largest production year was 1899, when output was about 320,000 ounces, then a record for Queensland which stood for over 100 years thereafter. The mines were closed thereafter due high costs and limited skilled labour.
The mineralisation is of the “orogenic lode gold” type, comprising mesothermal reefs of quartz containing gold and sulphide minerals, including galena, sphalerite and pyrite, hosted by granitic bodies. The reefs are usually 1-2 metres thick but have strike lengths from several hundred meters up to 2 kilometres in the Central area.
Area of mineralisation is very large, over 40 kilometres across, with reefs dating to 404-408m years (Late Silurian to Early Devonian). The host rocks are Ordovician to Silurian granites, granodorites and tonalites, and some metamorphics, largely mica schists.
The gold is fine-grained, mostly less than 1mm. Most particles are late-stage and located along grain boundaries, with minor amounts contained within sulphide grains, mainly pyrite, readily liberated through the cyanide process. The ore is not refractory and recoveries are said to be 97-98%.