The Bisha Mine in Eritrea, with 12+ years of current reserves, ranks as one of the highest grade open pit mines in the world.
Nevsun Resources Ltd. is pleased to advise that the Bisha Mine copper expansion project (“project”) is proceeding well against schedule and budget.
The Bisha copper expansion project will expand ore processing capacity from 2.0 to 2.4 million tonnes per year and convert from gold/silver doré to copper concentrate production. Annual run-rate copper production is expected to be 180 million pounds of payable metal per year, in concentrate with significant gold and silver by-product credits.
The copper plant total spend forecast remains approximately $100 million and hot commissioning is scheduled for Q2 2013.
The project is currently tracking within schedule and budget. As at the end of May, approximately 60% of the project was committed (ordered and price fixed). The remaining un-committed budget includes a relatively large $7 million in contingency.
COPPER PLANT PROGRESS
With all major process critical and long lead orders placed, the current project activities include outstanding procurement, equipment delivery, completion of civil works and commencement of steel erection. Most of the major equipment, including all the copper flotation cells, has arrived at Bisha and is awaiting installation. The filter press frames, regrind mills, concentrate thickener, mill cyclones and regrind cyclones are in transit. Foundations for the cells, racking, reagents store, and workshop will soon be complete. Assembly and installation of the plant equipment is expected to commence this month.
COPPER CONCENTRATE BULK HANDLING UPDATE
After careful consideration of various bulk shipping alternatives to smelters, the Rotainer system has been chosen for delivery of concentrate into bulk shipping carriers, using the existing Massawa container port. Rotainer and Rotainer equivalent systems are proven in both the iron ore and copper concentrate industry, mainly in Australia.
Concentrate will be trucked in specially built, Rotorcon reusable intermodal containers from the Bisha Mine site to the port of Massawa, and stacked at the existing container facility. Container trucking will be contracted and no specialized prime mover (truck) or trailer equipment is required. The copper concentrate containers will be discharged into the bulk carriers using Rotainer`s Lid-Lift crane equipment which rotates the container a full 360 degrees after lifting the lid.
The Rotainer system is designed with industry leading dust suppression allowing Bisha to operate out of the existing Massawa container port. The environment is a key focus for the State of Eritrea and the Rotainer system meets both the needs for copper concentrate export while setting high environmental standards for mining operations in Eritrea.
The estimated capital cost of the Rotainer system and containers is expected to be under $25 million.
Effectively this Rotainer system is in substitution for the need to develop dedicated bulk handling facilities at the port of Massawa for the Bisha concentrate. The Company will take responsibility of the cost and control for commissioning of the Rotainer system, which reduces schedule risk. Nevsun is confident that the Rotainer system will be operational for copper concentrate shipping, starting in mid-2013.
Cash on hand and from Bisha operations is more than sufficient to pay for the remaining cost of approximately $80 million for both the copper plant and the rotainer system.
The Bisha copper expansion project (“project”) will increase ore throughput from 2.0 to 2.4 million tonnes per year and convert from gold/silver doré to copper concentrate production. The open pit mine, crusher and grinding circuit remain unchanged. The bulk of the project capital cost is constructing a copper flotation plant and copper concentrate load out facilities. The existing carbon-in-leach (CIL) processing plant will be on care and maintenance in a condition so that it could be re-commissioned if additional gold oxides at or near Bisha are found.
The project budget is $100 million and production is scheduled for mid-2013.
The project is being built under EPCM contract by SENET of South Africa. SENET was the same contractor who successfully built the original Bisha plant on-time and under budget.
COPPER FLOTATION PLANT PROCESS
The copper flotation plant is a standard two stage design with re-grind. Ground ore from the milling circuit is fed to the rougher flotation circuit. Rougher concentrate is sent to the primary cleaner flotation circuit. Primary cleaner concentrate is sent to the concentrate thickener. The primary cleaner tailings are sent to the regrind circuit. After re-grind the material is delivered to the secondary cleaner flotation circuit. Secondary cleaner concentrate is sent to the concentrate thickener. Secondary cleaner tailings is combined with the rougher flotation tailings and sent to the existing tailings thickener and on to the tailings management facility. Thickened concentrate is dewatered in filter presses and stored in bulk.
Concentrate is blended and trucked 340 km to the Port of Massawa on the Red Sea for bulk export to copper smelters worldwide.
The new flotation plant and copper concentrate load-out facility are being constructed north of the current CIL plant per Figure 1 – Project General Arrangement. The facilities being constructed include the flotation plant described above, reagent handling area, workshops, concentrate thickening and storage, concentrate load-out and related support infrastructure.
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