Cookes Creek Tungsten

Hazelwood’s focus in Australia is the 100% owned Cookes Creek Tungsten Project in the East Pilbara of Western Australia. Hazelwood has worked towards de-risking this project as a future source of feedstock for its downstream ferrotungsten business in Vietnam.

The project is situated approximately 220 kilometres northwest of Newman and 30 kilometres northwest of Nullagine. Granted tenure covers the entire Cookes Creek Granite around which are myriad exploration targets and historic tungsten mining centres.

The Company’s evaluation efforts have been directed at the advanced, near-surface Big Hill Tungsten Deposit for which a definitive feasibility study is in progress. A pre-feasibility study showed a 12 year operational life for Big Hill, capable of supplying up to 2/3rd of the feedstock for the downstream processing business. Big Hill is a pure tungsten project that is not plagued by contaminants such as Arsenic, Tin, Molybdenum or base metals.

Product Quality

Noble metals often occur in polymetallic deposits. The Big Hill Tungsten Deposit is purely a tungsten deposit without contaminants such as arsenic, tin, molybdenum and base metals. From surface to the bottom of the defined resource, Big Hill hosts clean, easily recoverable tungsten mineralisation in the form of the mineral scheelite.

Hazelwood has demonstrated a reliable process route for the recovery of high purity tungsten concentrate.

Large scale pilot processing testwork on bulk samples has provided samples of saleable material that satisfy end-users specifications. Since the acquisition of a majority stake in the ATC Ferrotungsten Project, Hazelwood has become its own customer for future production from Big Hill. The high quality tungsten feedstock from Big Hill offers a competitive advantage to Hazelwood’s vertically integrated tungsten business.

History

Tungsten was mined from the historical Cookes Creek mining centre during the 1950’s and 1960’s. The mining activity during that era targeted narrow vein hosted mineralisation. The project is the largest recorded historic production centre for tungsten in the Pilbara.

At the Big Hill target, extensive diamond drilling, costeaning and significant metallurgical testwork was conducted during the 1980’s by Kalgoorlie Southern Gold Mines NL and Mitsui Mining and Smelting Co. A shallow dipping zone of sheeted vein scheelite – fluorite mineralisation was delineated.

Surface apparent widths of mineralisation at Big Hill of up to 70 metres at 0.28 per cent WO3 were returned from channel sampling. 40 diamond drillholes completed on a nominal 50 metre by 25 metre pattern, confirmed the continuation of significant mineralisation at depth, and the deposit remained open down-dip.

In addition to Big Hill, several other occurrences of scheelite mineralisation were noted, flanking the Cookes Creek Granite, which is considered the source of mineralisation. Rock chip samples of up to 7.6 per cent WO3, stream sediment anomalism and significant drillhole intercepts were returned from a number of localities.

Hazelwood’s Activities

The Company’s tungsten interests at Cookes Creek are held through its wholly owned subsidiary BigHill Resources Limited, which takes its name from the leading Big Hill Tungsten Deposit.

Hazelwood has worked to de-risk the Big Hill Tungsten Deposit, rather than on greenfields speculative exploration. The Big Hill Deposit has been drill tested by more than 300 holes for in excess of 27,000 metres, with most of this completed recently by Hazelwood. In places the drilling is closer spaced than 10m x 10m. Due to the shallow dipping geometry and readily accessible mineralisation, the average drillhole depth is less than 80 metres. Mineralisation remains open at depth.

A pre-feasibility study provided a strong case for the development of the Big Hill Deposit, based on low grade bulk mining and efficient ore sorting and gravity processing techniques to provide clean feedstock for ferrotungsten production.

JORC Resource & Ore Reserve

The Company’s intensive drilling effort has led to a de-risking of the Mineral Resource, which is largely in the advanced Measured and Indicated categories under the JORC reporting system. Most of the resource is within 100 metres of the surface. Hazelwood prefers not to make use of Inferred Resources in its economic assessment of projects due to their greater risk.

Two processing options were investigated, one with ore-sorting pre-concentration, the other without ore sorting. A total of 35 process flowsheets and general arrangement drawings were derived, with mass and energy balances. The ore sorting option was selected on the basis of overall operational efficiency.

Ore is subject to three stages of crushing and ore sorting via X-ray transmission detection. Ore sorting is a proven technology in use at many operations including operating tungsten mines. The ore sorted product is transferred to a rod mill and reduced to an 80% passing size of 950 microns. Beneficiation takes place on conventional spirals and tables. No flotation is required in this circuit. 

Projected processing costs for the ore sorting route were estimated at $11.39 per tonne of ore processed (December 2009 costs).

Groundwater exploration during the prefeasibility study identified the majority of the project’s water needs within 5 kilometers radius of the proposed mine. Additional water exploration and test bores are proposed during the definitive feasibility study.

Hazelwood adopted industry best practice in its environmental monitoring by conducting flora and fauna surveys early in the evaluation schedule. Most of the required environmental surveying has been completed and there appear to be few obstacles to the development of the Big Hill Tungsten Deposit. Environmental assessment documents are likely to be lodged towards the end of the definitive feasibility study.