The Ecstall Story: The Transition from Pit to Underground

"FROM THE BEGINNING OF THE PIT, it was known that the surface mining method had a projected life of about ten years, and that the ore extended to depths recoverable only by underground mining. When serious consideration was given to underground mining in 1968, it was realized that tremendous advantages could be gained by starting the underground mine as early as• poss1ble. These included: 1. The availability of underground ore for grade control, which would become more difficult as the pit deepened. 2. The need to develop new systems, equipment and skills to take full advantage of the technological revolution in underground mining. 3. Early knowledge of rock behaviour through trial mining on a small scale prior to finalizing plans for major blocks. In addition, the pit would be available to guarantee the mill supply if problems were encountered. 4. With sufficient time and early mining experience a much better job could be done on all mine planning. Because ample reserves of economic underground ore were virtually assured, the desired underground mining capability became a function of two restraints: first, the time required to excavate and construct the permanent headframe, shaft and ore-handling facilities necessary to handle large volumes of stope ore; second, the time for lateral and stope development on at least one level which would normally follow shaft sinking. The decision made was to move immediately on the permanent hoisting installations and at the same time embark on the planned ramp from surface, which would allow much stope preparation to be completed prior to .bringing the shaft on stream. Both projects were placed on an urgent basis early in 196S' and the following decisions made shortly thereafter."