Copper Mountain Mine (BC) Ltd. (CMM), which is 75% owned by Copper Mountain Mining Corporation (CMMC) and 25% owned by Mitsubishi Materials Corporation (MMC), is located 20 km south of Princeton, British Columbia, Canada.
CMM has produced copper concentrate since the mine reopened in 2011. Since 2017, a Geo-Met program has been carried out as a cooperative project by geologists and metallurgists of MMC and CMMC. The objective of this project was to understand the variance of flotation performance for various ore types throughout active mining areas and to map out the CMM mine site on a copper recovery basis to improve the accuracy of the copper production forecast.
It was revealed that copper recoveries were correlated with grain size of copper minerals, especially chalcopyrite, which is the primary copper mineral of the deposit. At first, blast-hole cuttings were visually observed in four active mining areas (Pit2 South, Pit2 West, Pit3 Stage3, Oriole Pit). The cuttings were classified based on the grain size of chalcopyrite or bornite, such as “(Very fine (<0.1 mm)”, “Fine (0.1 mm - 1 mm)”, “Medium (1 mm - 3 mm)” and “Coarse (>3 mm)” in order to understand the distribution of ore types throughout the area.
In addition, diamond drill-hole cores were re-logged with copper mineral grain size information to understand the ore type distribution at depth and in future mining areas. The observations of copper mineral grain size were quite consistent from the surface and at depth within the same area. Both observations of blast-hole cuttings and historical drill-hole cores were compiled and modelled in a mining software, Surpac. A laboratory flotation campaign for composite mining packets was conducted to understand the copper recovery behavior in the rougher flotation for various type of ores. As a result of studies from geological and metallurgical observations and test works, four copper recovery domains were created. These four recovery domains are predominantly classified by copper minerals grain size observations. They are defined as “Very fine to Fine”, “Fine”, “Fine to Medium” and “Medium to Coarse”.
The estimated copper recovery with the newly established recovery domains for the period of July 2016 to July 2017 fell into line with the actual mill performance. It was concluded that these copper recovery domains would improve the process of forecasting production and contribute for more accurate production budgeting.
As a result of this project, the copper recovery domains have been established and introduced into a block model and utilized for the actual budgeting and mine planning process since the first campaign was completed in 2017.
