Kennecott Copper Corporation

Limin Hsueh

Ray V Huff

Donald H Davidson

Robert A Hard

Peter James Lingane

Lawrence MacLagan Cathles, Iii

Method and apparatus for introducing finely divided gas bubbles into a lixiviant used for in-situ mining of minerals containing metal values, such as copper values. The lixiviant is supplied to a plurality of porous tubes formed of sintered powdered metal while a gas is supplied under pressure about the tubes to cause the gas to penetrate into the interior of the tubes in the form of fine bubbles which are wiped from the interior of the tubes by the lixiviant passing therethrough. The method and apparatus can be advantageously employed in situations where it is desirable to perform in-situ mining with an oxidizing lixiviant. In these cases oxygen is supplied under pressure about the tubes.

In-situ method and apparatus for sparging gas bubbles

An environmentally compatible, industrially safe, and potentially economic means for recovering copper and/or nickel from deep-seated deposits without resorting to extensive underground development. A two-phase ammoniacal leach solution containing oxygen bubbles is forced under high pressure through an injection hole several thousand feet deep into a leaching interval of a deep lying deposit containing copper or nickel or copper and nickel. The two-phase leach solution travels through the leaching interval of the deep lying deposit and is pumped out of withdrawal holes spaced apart from the injection hole. The two-phase leach solution under high pressure (more than 500 psi) penetrates the deposit through cracks, fissures and fractures, leaching copper and/or nickel along the way. Under a controlled pressure gradient, the leaching solution migrates over a period of time to receiving holes from which the pregnant leaching solution is withdrawn. The pregnant solution is then processed for recovery of copper or nickel or copper and nickel before it is returned to an injection hole. A method and apparatus for producing the two-phase leach solution and for maintaining a system in which the gas bubbles are able to penetrate the deposit is disclosed. Also disclosed are various parameters, such as hole spacing techniques, hole completion techniques and stimulation techniques.

In-situ mining method and apparatus

A process is disclosed for in-situ mining of copper from a subterranean ore body characterized, at least in part, by the presence of a sulfidic ore and by natural, microscopic fracture openings. The process comprises forcing a stable, two-phase lixiviant comprising an aqueous phase, a multiplicity of gaseous, oxygen-containing bubbles having a size sufficient to pass through the natural fracture openings in the ore body, and a surfactant for enhancing the formation of the bubbles and for minimizing bubble coalescence through the ore body to leach copper. The aqueous and gaseous phases of the lixiviant are mixed at the surface and injected into the leaching interval through an injection hole, or preferably, are mixed in a subterranean sparger within the hole above the leaching interval. The pregnant liquor is recovered through one or more production holes and, after the copper is recovered, the lixiviant may be reconstituted and recirculated.

In-situ mining of copper and nickel

This invention pertains to a method for in-situ mining of copper values from ore formations and, more particularly, this invention pertains to oxidative in-situ mining of copper wherein, for example, an oxygen-acid, a ferric iron-acid or a nitrate-acid lixiviant is being employed for recovering copper values. Further, this invention pertains to the recovery of copper from a deposit in which the ratio of pyrite to chalcopyrite is low. Still further, this invention pertains to a combination of acid-preinjection, monitoring, acid adjustment and additional monitoring or tell-tale ion monitoring for acid supply increase or decrease in the ore formation as steps in a combination for rendering highly controllable the acid preinjection process, thus providing further improvements to in-situ mining processes. Additionally, this invention pertains to a broad range of in-situ leaching processes including, for example, oxidative leaching of nickel sulfides, molybdenum sulfides or rhenium sulfides, or an oxidative leaching of pitch blende.

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Bedford, MA, United States of America

Limin Hsueh