Implementation of Electronic Detonators at Barrick Goldstrike Mines, Inc

摘要

In March of 2001 Barrick Goldstrike Mines, Inc. began evaluating the potential benefits of electronic detonators at the Betze Post open pit gold mine. The original evaluation focused on increased fragmentation, and excavator productivity. During the original evaluation there was an attempt to quantify mill throughput. Early tests indicated that there would be a benefit to mill throughput, however management was hesitant to take on the added cost of electronic detonators based on the initial evaluation. In early 2002 a decrease in mill throughput was being forecast as a result of harder ore being encountered. As a result of the initial electronic detonator evaluation a team of individuals from the Open Pit and Process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative. This initiative was targeted at improving mill throughput as the harder ores were encountered. Batch tests were conducted to determine if adjustments to drilling and blasting in the open pit could increase mill throughput and justify a 50% increase in drilling and blasting costs for the harder ore material. Mill throughput was increased through: 1) The use of electronic detonators allowing for high-speed precise timing. 2) Increased shock energy through the use of a high VOD Ammonium Nitrate. 3) Improved explosive distribution by decreasing pattern spacing and hole diameter. Digital analysis, plant operating data, and circuit surveys were used to quantify the gains in mill throughput. A micro-fracture analysis of the blasted material was also conducted using a scanning electron microscope. There was clear evidence of micro-fractures in the D2M material. The results of the batch tests indicated that an increase in mill throughput of 5% to 10% could be attributed to the optimized drilling and blasting techniques using electronic detonators. A rock response study was conducted in order to optimize the delay intervals to produce the best fragmentation in the D2M material. Four test blasts were monitored to define rock mass response, and four methods were used to determine the range of P-wave or seismic velocity of the D2M material. Based on the results of these tests a range of delay intervals between holes in a row and the delay interval between rows has been effectively defined. The resulting optimized delay intervals would not be possible without the use of electronic detonators. As a result of the D2M Continuous Improvement initiative the Barrick Goldstrike management team made an economic based decision to implement the use of electronic detonators along with the high VOD Ammonium Nitrate in the ore. The recognized gain in mill throughput offset the increase in drilling and blasting costs.