Located at Rosebery, on Tasmania's North West Coast, the underground mine has operated continuously since 1936. Current exploration aims to achieve a mine life beyond 2020.
The mine produces approximately 700,000 tonnes of ore, which we process into concentrates containing zinc, lead and copper. Silver and gold is also extracted from the ore and cast into dore bars.
The orebody, extends for approximately 2 kilometres north-south and to a depth of 1.5 kilometres. The polymetallic nature of the orebody enables us to achieve a significant relative cost advantage after by-product credits compared to many of its global peers.
The mine is an important part of the regional economy and social fabric of Tasmania's North West Coast.
Key statistics
| Name |
Rosebery |
| Location |
Located at Rosebery, on Tasmania's North West Coast in Australia. |
| Product |
zinc concentrate, concentrate, gold doré |
| Reserves* |
0.42 million tonnes zinc, 0.12 million tonnes lead, 0.01 million tonnes copper, 0.18 million ounces gold, 10.17 million ounces silver |
| Resources* |
1.7 million tonnes zinc, 0.5 million tonnes lead, 0.1 million tonnes copper, 0.8 million ounces gold, 61.8 million ounces silver |
| Employees |
243 |
| Mining Method |
Mechanised underground mining |
| Start Date |
1936 |
* as at 30 June 2008
Key production statistics 2006/07
| Ore treated |
707,331 tonnes |
| Zinc concentrate produced |
150,619 tonnes |
| Contained zinc |
82,938 tonnes |
| Lead concentrate produced |
36,783 tonnes |
| Contained lead |
23,490 tonnes |
| Copper concentrate produced |
7,379 tonnes |
| Contained copper |
1,570 tonnes |
| Gold Dore |
559 kilograms |
| Contained gold |
324 kilograms |
View the latest Quarterly Production Report
Mining Operations
Rosebery mine uses mechanised underground mining methods, notably bench stoping, and sub-level open stoping with some mechanised cut and fill. Access to the mine is by a decline and all ore is trucked directly to the surface.
Concentrator Operation
The relatively soft Rosebery ore is subjected to two stages of crushing and two stages of grinding. Gold is recovered by gravity separation and smelted on site before being sold as dore bullion. Copper, lead and zinc concentrates are produced using sequential froth flotation. Tailings are treated then pumped to dam storages.
Concentrates are transported to the port of Burnie by rail where they are shipped in bulk carriers.
Exploration and future developments
Rosebery Mine has traditionally had a rolling mine life of six years. Our exploration program, Project Horizons, commenced work in 2006 and expanded the resource by 65 per cent to 11.7 million tonnes.
The potential for a small zinc resource was identified at the Jupiter prospect near the Rosebery mine.
A pre-feasibility study was carried out in 2007/08 to review the economic merits of renewing the surface facilities at Rosebery. While benefits from replacement of the grinding and flotation circuits at a cost of $125 million were identified, these are not essential in the short-term. The feasibility study will be completed and then the final design and construction phase will be deferred. Work on the new tailings storage facility and the underground ventilation upgrade will continue.
South Hercules
The South Hercules deposit, approximately 10 kilometres south east of the Rosebery Mine, has an indicated resource of 1.1Mt at 2.7% zinc, 1.4% lead, 99g/t silver and 1.6g/t gold. A feasibility study into mining the deposit and processing the ore through the Rosebery mill was deferred in 2008.
Que River Bass Metal Project
Utilisation of the assets at Rosebery Mine was improved in 2008 with an agreement with Bass Metals Ltd to purchase ore from the first stage of its Que River Base Metal Project on the North West coast. The agreement allows for MMG to purchase 120,000 tonnes of ore from Bass Metal over approximately two years at an average of 8.3% zinc metal content.
Tasmanian North West Coast Exploration
In western Tasmania MMG exploration is progressing over 448km2 of the Mount Read Volcanic arc sequence host to the polymetallic, Rosebery, Hellyer and Que River deposits.
Production
In 2008, 84,939 tonnes of zinc in concentrate, 28,674 tonnes of lead in concentrate, 2,062 tonnes of copper in concentrate and 30,675 ounces of gold doré was produced at Rosebery.
Production (contained metal in concentrate) for 2009 is planned to be 80,000-90,000 tonnes zinc, 20,000-25,000 tonnes lead, 15,000 to 20,000 ounces of gold and 1.75-2.0 million ounces of silver.
View recent production results.
Safety, Health and Environment
Rosebery Mine management are committed to safety, health and environment.
At Rosebery, management are committed to achieving zero harm. We have recorded significant improvements to both our medically-referred and lost-time injury rates during the past four years. Initiatives such as our wellbeing program, and enhancements to our injury management process β including timely and supportive rehabilitation management β have sustained these reductions.
We have introduced a behavioural safety program β with all site personnel completing at least one safety observation per month. Our aim with the observation program is to provide two-way feedback between the operator and observer. The program has improved our hazard and near-miss reporting, enabling us to focus on preventable measures to avoid incidents.
We have identified blood lead as a key health risk to our personnel due to the production of lead concentrate on site. We have developed a blood lead management program and awareness campaign
We have also developed a wellness program to promote improved wellbeing, fitness and nutrition among our workforce. This is part of our commitment to providing a safe place of work, and to help ensure that all employees and contractors are βfit for work'.
Environmental management at Rosebery is taken seriously. Initiatives have included the developed of a wastewater treatment facility whereby sewage from the Rosebery township is redirected from the Stitt River to the mine's water treatment system. The site has been reviewing operations tailings dams which are no longer used for mining operations but are where the town sewage is treated. Currently, the sewage requires further treatment along with mine wastewater before it can be discharged, but Rosebery mine is working on the longer-term goal of making the old tailings dam area a self-sustaining system with wastewater quality suitable for direct discharge. This will allow treated water to be discharged to the Stitt River and for the town's sewage treatment system to operate independently after the mine closes.
Rosebery Mine Sustainable Development Report 2007
Rosebery Mine Sustainable Development Report 2006
Rosebery Mine Sustainable Development Report 2005
Geology
Rosebery's ore is a complex of metal sulphides containing lead, zinc, copper, silver, gold and iron. The ore is contained within a host rock of fine-grained sediments which were laid down in an active volcanic region, known as the Mount Read Volcanics, about 600 million years ago.
The ore body as it is know extends for approximately 2,000 metres, north-south and to a depth of 1.5 kilometres.
