From my limited understanding Macka the other option is...

From my limited understanding Macka the other option is pyrometallurgy (melting the ore) but usually applies to saprolite ores ,energy requirements are high and grades of nickel need to be higher ie above 2%. HPAL (high pressure acid leach) also requires grades >1.4% Ni, but heap leach will depend on soils being relatively low in clay to allow Ni to seep to the bottom of the 'heap'. Early days, we don't know enough yet. With all options one of the costly and problematic factors is that there is a sh1tload of waste.