Controlled in-situ leaching of mineral values

Abstract

Abstract A freezing liquid, usually a liquified gas easily vaporized by the absorption of heat, e.g. liquified oxygen or nitrogen, is injected into or around an underground area to be treated for the recovery of solid mineral values, usually a naturally occurring deposit of such mineral values as copper sulfides or oxides or a mine waste dump containing same. When injected under pressure into an area of low permeability, the freezing liquid effects hydraulic fracturing of the mineralized solid materials. Control of the operation is preferably achieved by freezing either natural ground water or injected water in boundary zones, e.g. relatively pervious zones adjacent to relatively impervious zones, to provide barriers against dissipation, into such boundary zones, of both the injected freezing liquid and subsequently injected leaching or other treatment fluid. In the instance of natural ground water at least, air under pressure may be advantageously introduced into the area to be treated immediately prior to the introduction of the freezing liquid. When sulfide minerals are involved, liquid oxygen as the freezing liquid will aid in fracturing the underground formation by reason of volume increase due to chemical reaction with the sulfide.

Inventors

• 👤 H Spedden
• 👤 E Malouf

Bibliographic Details