Chalcopyrite leaching followed by precipitation of other minerals
Prerequisites for leaching (mobilisation) and precipitation (immobilization) of the mineral chalcopyrite (CuFeS2) are that the chalcopyrite is in close contact with pyrite which, in conjunction with rain/snow/fog may be oxidated (i.e. in air) and form diluted sulfuric acid which will leach copper from chalcopyrite and then precipitate it as chrysocolla or malachite.
Precipitation takes place as pH regains neutrality, that is when the pyrite has been diluted with enough rain/snow/fog on its way down the mountain (on condition that no more pyrite is oxidated on the way down). Precipitation may also be influenced by for example carbonate-streaks along the steep rock face which the solution passes. If it passes a calcite-streak the sulfuric acid will be neutralised and malachite can be formed. Air also contains carbon in the form of carbon dioxide (today about 400 ppm, and increasing because of the massive carbon combustion and the traffic), so ordinary oxidation with O2 + CO2, and also CO, may cause thin surfaces of malachite (and/or azurite - deep azur-blue carbonate mineral).
Pictures showing leaching, with or without microbes, look exactly the same in macro scale.
Reaction of leaching and precipitation
Chalcopyrite + Pyrite + O2 + H2O => chrysocolla / Malachite + Fe-oxid/hydroxid