While trolling around for something interesting, I came across the term In-Situ Recovery. In-Situ Recovery, In-Situ Mining or In-Situ Leaching, according to Wikipedia, is a mining process used to recover minerals such as copper and uranium through boreholes drilled into a deposit, in situ. In situ leach works by artificially dissolving minerals occurring naturally in a solid state.
This process involves pumping of a lixiviant into the ore body via a borehole, which circulates through the porous rock dissolving the ore and is extracted via a second borehole.
Thor Mining plc an AIM listed mining company with tungsten and copper projects in Australia and the USA. Metal Tiger plc (LON:MTR) has an investment of 51,350,000 ordinary shares at 31 December 2017 representing 8% of the issued ordinary share capital of Thor Mining.