Philex Silangan – The Effects of Copper Mineralogy
Since 2010, SRK has been working with Philex Mining Corporation on its Silangan project, located on Mindanao Island in the Philippines. For this copper-gold project, SRK was requested to investigate block caving as the mining method - a particular challenge considering this is a high rainfall area. However, Philex personnel are very knowledgeable about this mining method since they have used it successfully at the Padcal operation.
One of the features of the Silangan ore is its variable mineralogy, in which copper can exist as sulphides, carbonates, oxides, and silicates. As block caving must balance many aspects to maintain a steady drawdown of ore, it is not easy to mine certain areas selectively and the process is somewhat inflexible in terms of ore blending. Consequently, the Silangan process flowsheet must be developed to handle a wide range of ore types.
To better estimate the impact of mineralogy on process recovery, copper speciation analysis is being included in the resource block model. Copper speciation analysis estimates the relative amount of non-sulfide (acid soluble) and secondary sulfide (cyanide soluble) copper minerals.
In the figure above, the coloured surface represents the volume of ore contained in one of the Silangan deposits that has a relatively high, acid-soluble copper content. SRK is using Gemcom’s PCBC™ software to simulate the mixing that is expected to occur as the ore is removed from the drawpoint level beneath the caving zone. The white outline (or footprint) of the drawpoint level, as determined in PCBC, is also shown.
The combination of block cave simulation with the PCBC software, along with copper speciation results collected on drillcore samples, will allow SRK to accurately estimate copper and gold composition and performance for a range of ore types. This information allows more detailed economic analysis of the mine scheduling/planning process.
