Modern Mining June 2015

MINING News

The north-west pit at Kansanshi showing the area of the record-breaking blast (photo: BME).

Another BME blasting record in Zambia

its own digital initiation system. The system allocates precise firing times to detonators, allowing engineers to design complex firing sequences in a blast to achieve desir- able and repeatable blast results. “Everything went according to plan, with the logging, programming, status check and the blast itself all on schedule and with good results,” said de Bruin. “We are now only 645 detonators away from the overall African record.” BME has been a pioneering force in the field of electronic detonation, which is growing in popularity as more mines and quarries benefit from the reliability and accuracy of these devices. According to BME Technical Director Tony Rorke, the accuracy of electronic deto- nators is not only making blasting practice more predictable, but is also allowing for larger and more cost-effective blasts. Now the leading supplier of explosives to the South African open-pit mining and quar- rying industry, BME is also an innovator of various blast-related services and products. “The use of shocktube (non-electric) detonators has always had the limitation of being reliant on hard-wiring throughout,” said Rorke. “This places certain constraints on the blast design and implementation, and can raise the risk of a mis-fire under certain conditions.” The advantages of using electronic det- onators include the ability to trigger blasts through a wireless signal. Included in these are that blasting lines to the detonators are less likely to be damaged, thereby substan- tially reducing the likelihood of a mis-fire. 

Leading explosives supplier BME has raised the bar with a record blast at Zambia’s Kansanshi mine in March 2015, detonating 4 141 electronic delay deto- nators (EDDs) in a single blast in the operation’s north-west pit. “This is a great achievement for the BME team in Zambia and another milestone for the AXXIS system,” said BME’s Country Manager in Zambia, Charles Pretorius. “It is our second record for the most EDDs in

one blast for BME world-wide, beating our own record of last year.” Wayde de Bruin, the Senior Operations Manager on site, said the blast comprised a main block, as well as trim just above the main block. The blast was done using one master blasting box at the point of blast- ing communicating remotely to the slave boxes and detonators down in the pit. To improve the safety, ease of use and accuracy of blasts, BME developed AXXIS – increased focus on resource development at the Blanket mine. The rate of explora- tion drilling has increased and will increase further when the new drill machines, which have already been ordered, are delivered and commissioned. “The upgrade of approximately 491 000 tonnes from inferred resource to indicated resource represents a significant improve- ment in the overall confidence level of Blanket’s resources.” When the Preliminar y Economic Assessment was completed in late 2014 for the revised investment plan at Blanket mine, approximately 55 per cent of Blanket’s resource base comprised measured and indicated resources and 45 per cent com- prised inferred resources. After the upgrade, the resources split has improved to 62 % in the measured and indicated category and 38 % in the inferred category. 

Blanket mine upgrades its resource base Canada’s Caledonia Mining has announced an increase and upgrade to the resource base at its 49 %-owned subsidiary, the Blanket mine in Zimbabwe.

Based on the drilling that has been com- pleted at depth below the AR Main and Blanket sections over the past year, it has been possible to upgrade 491 000 tonnes from the inferred to the indicated resource category and to add 47 000 tonnes of new inventory to indicated resource. This upgraded indicated resource of 538 000 tonnes is additional to the 2,93 Mt of reserves and indicated resource that was used for the Reserve Plan in the Technical Report prepared by Minxcon in December 2014 and represents an increase of 17,4 % in terms of tonnes and 20,5 % in terms of contained gold. Commenting on the resource upgrade, Steve Curtis, Caledonia’s Chief Executive Officer, said: “This upgrade reflects an

10  MODERN MINING  June 2015