Appeal No. 2000-0012
Application No. 09/024,413
stacking the treated ore in a heap less than twelve meters
high;
irrigating said heap with a dilute aqueous solution
consisting essentially of sulphuric acid and sodium nitrate to
produce a leach product, whereby said sodium nitrate is consumed
in the production of the leach product;
collecting said leach product from said heap; and
recovering metal from said leach product by electrolysis to
produce a depleted leach product.
The examiner relies upon the following references as
evidence of obviousness:
Stetefeldt 287,787 Oct. 30, 1883
(Patent Specification)
Mackay 1,737,425 Nov. 26, 1929
Keyes 2,009,667 Jul. 30, 1935
Abell et al. (Abell) 3,269,832 Aug. 30, 1966
Carnahan et al. (Carnahan) 3,912,330 Oct. 14, 1975
Kintaichi et al. (Kintaichi) 5,336,476 Aug. 9, 1994
Altaev et al. (SU '761) SU 1581761 Jul. 30, 1990
(Soviet Union Inventor's Certificate)
Appellant's claimed invention is directed to a method for
removing metal, such as copper, from sulphide ore without adding
gaseous oxygen and without producing NOx gases. The method
involves agglomerating crushed ore by treating with concentrated
sulphuric acid and stacking the ore in what is known in the art
as a heap. The heap is irrigated with a dilute aqueous solution
of sulphuric acid and sodium nitrate which produces a leach
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