Abstract: A heap leaching method to recover copper from a primary copper sulphide mineral wherein the mineral is leached in an acidic chloride/sulphate solution in the presence of oxygen with the surface potential of the mineral below 600 mV (vs. SHE) to cause dissolution of the copper sulphide.

Abstract: A heap leaching method to recover copper from a primary copper sulphide mineral wherein the mineral is leached in an acidic chloride/sulphate solution in the presence of oxygen with the surface potential of the mineral below 600 mV (vs. SHE) to cause dissolution of the copper sulphide.

Abstract: A laser protection device employing a gas plasma switch wherein applied laser radiation is focused inside a gas chamber, and a nuclear source is employed to pre-ionize the gas volume, whereupon focused laser radiation causes gas breakdown and plasma formation that attenuates the radiation. Specifically, the invention reduces the threshold of plasma switch initiation by incorporating a nuclear source within the gas chamber that constantly injects plasma forming seed particles into the vicinity of a focused laser beam. The plasma resulting from avalanche ionization of the seed particles reflects, absorbs and deflects the laser radiation. The nuclear source introduces charged particles, excimers and metastable atoms with low ionization potential into the gas chamber. Such charged particles are effective plasma initiators because they have low ionization thresholds. The present invention has been found well suited to protect against pulsed laser sources because of fast rise times and high attenuation levels.