Since December 1996, Sirocco Resources N.L. (SRO) has been progressing planned recommencement of operations at it’s Toms Gully gold project near Darwin in the Northern Territory. The Toms Gully mine was last operated by Kakadu Resources Ltd in 1995.
A 3 staged development concept has formed the basis of this plan as follows:
Stage 1 - Re-commissioning of the existing process plant using tailings from the previous operations, followed by open cut ore sources from the nearby Quest 29 prospect.
Stage 2 - Commence mining operations from underground at Toms Gully and blend this ore with ore from Quest 29.
Stage 3 - Optimize the operation.
In the pre-feasibility study it is noted that the operational timing is not prescriptive. Current thinking involves allowing about 1 year for each stage to be completed. The staging is being undertaken to minimize capital expenditure from capital reserves. The pre-feasibility study focuses on Stage 1 of the plan. This notice of intent is for this Stage 1 only. A revised notice of intent will be issued for Stage 2 (recommencement of mining operations from underground) at that time.
Detailed drilling to shallow depths (<50m) at Quest 29 in 1997 delineated a total resource of 2.2 million tonnes at 2.0 g/t Au (138,000 contained ounces of gold) in two zones, the West Koolpin and the Zamu Dolerite. A separate report providing details of this programme has already been submitted to the Northern Territory Department of Minerals and Energy. During the pre-feasibility study, preliminary pit design showed that 0.8 million tonnes at 2.2 g/t Au (0.4 g/t Au cutoff can be mined from two shallow pits at a waste to ore ratio of 3.2: 1.
Cyanide bottle roll tests have been undertaken on 33 composite samples from both resources at Quest 29 to examine lateral and vertical variability within the resources. These tests have allowed characterization of two main ore types viz. oxide and sulphide (primary). There may also be a transitional zone in the Zamu Dolerite zone. Recoveries in the oxide zones are excellent exceeding 90%. Lower recoveries occur in the Zamu Dolerite sulphide zone in particular. Further development metallurgical testwork is currently underway to resolve the issues.
The pre-feasibility study discusses environmental issues particular to the project including:
- Dewatering of acid mine water in the Toms Gully pit
- Containment of all wastes including sedimentation on both sites
Toms Gully is an existing mine site with infrastructure well established to control all potential environmental hazards in accordance with all Government regulations. All necessary permits are in place. Quest 29, as a new operational site, will establish controls within the draft guidelines outlined in the pre-feasibility study report and this notice of intent.
Licenses were in place for controlled release of acid water from the Toms Gully open pit into the Mt Bundey creek, during high creek flow events in the 1998 'wet season'. Controlled release in past 'wet seasons' has been shown to be effective. Careful independent monitoring of these releases has shown no damaging environmental effects from water toxicity. Following the completion of the 1998 'wet season', storage of residual water will be in evaporation ponds. Continued dewatering of further inflows will take place, however, this water is likely to be neutral to mildly acidic and suitable for discharge into the landowner's artificial wetland.
Infrastructure and services at Quest 29 will be established generally using refurbished secondhand equipment. The access road from the Arnhem Highway to Rustlers Roost Mine road requires upgrading from the turnoff to the Quest 29 site (about 10 kilometres) for ore haulage to Toms Gully and access for equipment. Site roads, power and water supply, office and workshop, a heap leach pad, associated ponding and stripping columns, pit bunding, creek diversion and a siltation pond and waste dump site(s) will need to be established for Stage 1 at Quest 29. An office upgrade and refurbishment of the process plant at Toms Gully will also need to be undertaken for Stage1.
SRO proposes to employ personnel on individual contracts and will operate on various shift arrangements depending on the final configuration of Stage 1. An accommodation strategy involving nearby available local motels, as well as own housing with transport from Humpty Doo is being considered. Because of the project location, even commuting from Palmerston (Darwin), about 1 hours drive, may be possible.
The pre-feasibility study report concludes that further studies are warranted to enable a full feasibility study to be prepared by late July 1998 (current schedule). The work programme is detailed in the pre-feasibility study report.
The purpose of this notice of intent is to involve the Northern Territory Department of Minerals & Energy in a consultative planning role, thereby assisting the Company in its feasibility study planning. This will enable the Company to respond to Government requirements during the feasibility study and enable the project to proceed as soon as possible following completion of the feasibility study, the final notice of intent, formal Government approval and ultimately the Board's decision to mine.