TY - JOUR
T1 - Mineralogical and metallurgical study of supergene ores of the Mike Cu–Au(–Zn) deposit, Carlin trend, Nevada
AU - Barton, Isabel
AU - Ahn, Junmo
AU - Lee, Jaeheon
N1 - Funding Information:
Newmont Mining provided background geological data, assays, and samples for this project. Freeport-McMoRan Inc. prepared and analyzed the head and residue samples and donated QEMSCAN time for the mineralogy. The time and expertise shared by Dick Reid and Rachel Burgess (Newmont) and Martin Lyders, Veronica Alejandro, and Casey Cochran (Freeport) are particularly appreciated, as are the guidance and advice of Profs. Mark Barton, J. Brent Hiskey, Jinhong Zhang, and Eric Seedorff at the University of Arizona. The analyses for Au in thiourea leach liquors were performed by the Arizona Lab for Emerging Contaminants (ALEC) at the University of Arizona, Tucson, AZ. Comments from two anonymous reviewers helped to improve the manuscript.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/3
Y1 - 2018/3
N2 - The undeveloped Mike Cu–Au(–Zn) deposit on the Carlin trend of Nevada, USA, currently held by Newmont Mining, hosts an unusual suite of oxide Cu and Au minerals. This study evaluates the possibilities for economic recovery by 1) comparing the Cu and Au extraction achieved from the supergene ores by six different lixiviants, and 2) identifying which minerals cause low recovery for each lixiviant and why. Gold is present as auricupride and electrum and copper exists as conichalcite (Ca–Cu arsenate), native Cu, cuprite, chrysocolla, and minor malachite, with locally significant copper in jarosite, hematite, and goethite. The reagents tested were sulfuric, sulfurous, and methanesulfonic acids to recover Cu, cyanide and thiourea to recover Au, and glycine to recover both. No reagent recovered both Cu and Au effectively, although sulfuric and methanesulfonic acids recovered most of the Cu and cyanide and thiourea recovered most of the Au. Glycine recovered nearly all of the Au and >50% of the Cu from the cuprite- and native-Cu-dominated ore type, but did not recover much Cu or Au from any of the other ore types. This supports the hypothesis that Cu2+ catalyzes Au dissolution in glycine, and thus effective Au leaching by glycine from oxide Cu–Au ores may be contingent upon the solubility of the Cu minerals in glycine. Post-leaching QEMSCAN analysis indicates that conichalcite and Cu-bearing Fe oxides failed to dissolve completely in all reagents and were the principal causes of low recovery. In addition, native Cu dissolved only partly in thiourea, and chrysocolla dissolved only partly in thiourea, glycine, or cyanide. Other observed mineralogical changes include the total loss of dolomite and partial loss of alunite and iron oxide from all samples, with apparent gains in alunite and jarosite.
AB - The undeveloped Mike Cu–Au(–Zn) deposit on the Carlin trend of Nevada, USA, currently held by Newmont Mining, hosts an unusual suite of oxide Cu and Au minerals. This study evaluates the possibilities for economic recovery by 1) comparing the Cu and Au extraction achieved from the supergene ores by six different lixiviants, and 2) identifying which minerals cause low recovery for each lixiviant and why. Gold is present as auricupride and electrum and copper exists as conichalcite (Ca–Cu arsenate), native Cu, cuprite, chrysocolla, and minor malachite, with locally significant copper in jarosite, hematite, and goethite. The reagents tested were sulfuric, sulfurous, and methanesulfonic acids to recover Cu, cyanide and thiourea to recover Au, and glycine to recover both. No reagent recovered both Cu and Au effectively, although sulfuric and methanesulfonic acids recovered most of the Cu and cyanide and thiourea recovered most of the Au. Glycine recovered nearly all of the Au and >50% of the Cu from the cuprite- and native-Cu-dominated ore type, but did not recover much Cu or Au from any of the other ore types. This supports the hypothesis that Cu2+ catalyzes Au dissolution in glycine, and thus effective Au leaching by glycine from oxide Cu–Au ores may be contingent upon the solubility of the Cu minerals in glycine. Post-leaching QEMSCAN analysis indicates that conichalcite and Cu-bearing Fe oxides failed to dissolve completely in all reagents and were the principal causes of low recovery. In addition, native Cu dissolved only partly in thiourea, and chrysocolla dissolved only partly in thiourea, glycine, or cyanide. Other observed mineralogical changes include the total loss of dolomite and partial loss of alunite and iron oxide from all samples, with apparent gains in alunite and jarosite.
KW - Alternative lixiviants
KW - Automated mineralogy
KW - Conichalcite
KW - Leaching
KW - Oxide Cu–Au ores
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U2 - 10.1016/j.hydromet.2018.01.022
DO - 10.1016/j.hydromet.2018.01.022
M3 - Article
AN - SCOPUS:85041456780
SN - 0304-386X
VL - 176
SP - 176
EP - 191
JO - Hydrometallurgy
JF - Hydrometallurgy
ER -