From Green Field Site to Block Cave Mine - Results of Northparke's Drill and Blast Design Process

The green field site is one that has no history of mining and as such it presents the designer with a blank canvas, on which any number of drill and blasting options can be drafted. No matter which mining method is selected all technology and experience will need to be acquired from outside sources, applied quickly and produce the right results. North Limited, in joint venture with the Sumitomo Group (20 per cent), have developed AustraliaÆs first block cave mine at Northparkes in New South Wales, Australia. This innovative and large scale mining project was taken from a green field site in November 1993 to a fully commissioned block cave mine in December 1997. NorthparkesÆ Endeavour 26 mine is now producing at a rate of 3.9Mt per annum from a 27Mt ore block. Prior to 1993 no history of mining activity existed at Northparkes. The rock had never been blasted and many questions were raised about how it would behave. While it was clear that the Endeavour 26 (E26) orebody contained geotechnical properties appropriate to block caving, the blasting methods required to establish a block cave mine had never been used in Australia and no designs were available. The joint venture partners had no prior experience with block caving and it was immediately apparent that this blasting technology would have to be acquired from foreign sources and applied to the unique local conditions. Conceptual designs for the block cave drill and blast were first drafted in 1994, first issued for drilling in December 1995 and first blasted in January 1996. 470 km of drill metres and four million tonnes of rock were blasted to complete the undercutting project by September 1997. This paper will provide those developing new drill and blast projects with an inside view of how one small technical team solved many design challenges to successfully construct AustraliaÆs first block cave mine under strict quality controls and ambitious time constraints.