Overview
The Tropicana gold project is located 330 km east-north-east of Kalgoorlie, Western Australia.
The 13,000 sq km project is located in a remote region on the edge of the Great Victoria Desert and covers a 300 km strike length of an ancient collision zone between the Yilgarn Crater and the Albany-Fraser Province.
Some 1990s public data detailed a gold-in-soil anomaly that was delineated in the northern part of the tenements. In 2005, the company followed up the unexplained anomaly and discovered the Tropicana gold deposit.
Joint venture partners are Anglogold Ashanti (manager and operator) with 70% interest and the Independence Group NL which has a 30% interest.
In November 2010, the Boards of Directors approved the development of the gold project as an open-pit mining operation based on mineral reserves totaling 48 Mt at 2.2 g/t gold for 3.45 Moz. Strip ratio was calculated at 5.5:1.
Initial mine life was estimated at 10 years and average gold production would amount to 330,000 oz to 350,000 oz gold per year.
First gold production is expected in the December 2013 Quarter.
Location
Australia, Terra Australis in Latin, is a prosperous developed country located in the Southern Hemisphere. It was inhabited by hunter and gatherer Aborigines for about 40,000 years prior of being colonized by Europeans starting with the 17th century.
The first European to land in Western Australia was Dirk Hartog, a Dutch explorer. Nowadays the economy of the 2.5 million sq km state is based on mining, agriculture and tourism. The state is the third iron ore producer in the world.
Perth is the state's capital city and with a population of 1.7 million people it is Australia's fourth most populous city.
Laverton is a mining town founded as a result of a gold mining rush that occurred in 1896. In 1969, a time of depressed gold prices, an important nickel discovery was made by a prospector named Ken Shirley and as a result nickel mining heavily contributed to keeping the town afloat.
The 425,000 sq km Great Victoria Desert was first crossed by British explorer Ernest Giles in 1875. It is an active sand-ridge desert of Quaternary Aeolian sands. Scarce vegetation consists of eucalypts (Marble Gum), bushes and patches of grassland.
Tropicana gold deposit lies at its western fringes and baseline surveys found that more than 600 flora species occur within the perimeter of interest and some of them are rare or threatened species. Fauna studies also managed to identify a number of threatened species within the region.
The climate is arid, with average daily temperatures ranging from 15 deg C to 45 deg C in summer and 0 deg C to 30 deg C on winter time. The rainfall averages 150-200 mm annually and falls mostly as showers during the December to June period.
Geology
The Tropicana project covers a 300 km strike length of an ancient collision zone between the Yilgarn Crater and the Albany-Fraser Province.
Gold intercepts have previously been returned from the Tropicana prospect associated with broad intensely biotitic-pyritic and sericitic hydrothermal alteration zones, crosscutting a package of metamorphic rocks. Mineralization style is considered to have affinities to large intrusion related gold ore bodies such as Pogo in east central Alaska.
The Tropicana deposit consists of four mineralized zones namely Tropicana, Havana, Havana South and Boston. Mineralization is tabular and stratiform and dips 30 deg east to south-east.
At Havana mineralization was successfully intersected 1,000 m below the proposed Havana open pit base.
The Bankable Feasibility Study was based on a Proved and Probable Reserve of 48 Mt grading 2.2 g/t for 3.4 million ounces of gold.
As of 2010, AngloGold Ashanti was estimating a new resource including potential Boston Shaker open cut and Havana Deeps underground mineralization.
Mining & Operation
Mining is planned to be by conventional open pit drill and blast methods using trucks and excavators.
Three open pits would be sequentially mined at Havana South, Havana and Tropicana.
It has been assumed that bulk mining methods would be appropriate for waste material.
A total of 59Mt of ore and 328Mt of waste is planned to be mined using contract mining at an overall waste to ore strip ratio of 5.5:1
Processing
The open pits are expected to provide approximately 59 million tonnes of plant feed at an average grade of 2 g/t Au and produce 3.45 million ounces of recovered gold over a 10 year mine life.
The gold process flow sheet would include high pressure grinding rolls and ball milling to 80% passing 75 microns followed by a carbon-in-leach (CIL) circuit. The average recovery rate would be 90.4%.
The plant throughput on 100% fresh ore will be approximately 5.8 Mtpa and on a blend of oxide and fresh ores will increase to 6 Mtpa.
First gold production is expected in the December 2013 Quarter.
Despite the relative proximity to the mining hub of Kalgoorlie, the area is characterized by a lack of infrastructure. A substantial investment in supporting infrastructure including mine access roads (220 km), communications, power infrastructure, water supply (located 50 km from proposed plant site), fly-in fly-out accommodation village and sealed airstrip is required.
