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Exploration for Zn-rich mineralization in the semi-arid Cobar region of NSW, Australia

Keith M. Scott and Angela N. Lorrigan
Exploration for Zn-rich mineralization in the semi-arid Cobar region of NSW, Australia
Geochemistry - Exploration, Environment, Analysis (May 2011) 11 (2): 93-101


Soils from the vicinity of the Endeavor Mine, in the Cobar region of western NSW, have been sieved into the (a) 2-4 mm, (b) 1-2 mm, (c) 0.5-1 mm, (d) 250-500 mu m, (e) 125-250 mu m, (f) 63-125 mu m and (g) <63 mu m fractions, with a magnetic fraction (m) also prepared from the coarser soil fractions. The chemical compositions of these soil fractions show that the coarse (2-4 mm) and magnetic fractions contain the highest As, Fe, and Pb contents whereas the fine (<63 mu m) fraction is enriched in Al, Ca, Cu and Zn. Phosphorus and S have bimodal distributions. Elevated Pb and As contents in the coarse or magnetic fraction of soils in the Endeavor Mine area reflect the underlying weathered Pb-Zn mineralization and may give rise to a larger anomaly than that defined by conventional magnetic lag sampling. Within this area of Pb and As anomalism, the fine fraction of the soils directly above the Northern Pods mineralization (c. 400 m below) exhibit enriched Zn, S and soluble salt contents (the latter measured as electrical conductivity). The association of elevated Zn, S and EC (electrical conductivity) suggests sulphide-derivation and such anomalism appears more prospective than Zn-only anomalism in fine soil fractions from transported material to the SW of the mine. Unfortunately the preparation of the fine soil fraction is time consuming but, because the fine fraction of the Cobar region soils consistently represents 40-50% of the <2 mm soil fraction, the latter can be used as a surrogate for the fine soil fraction. Thus, cost effective exploration for base metal mineralization in the Cobar region could utilize the >2 mm soil fraction for determining Pb and As and the <2 mm soil fraction for S, Zn and EC. Use of the <2 mm soil fraction discriminants should be considered during exploration for Zn-only mineralization in semi-arid regions like that at Cobar.

ISSN: 1467-7873
EISSN: 2041-4943
Serial Title: Geochemistry - Exploration, Environment, Analysis
Serial Volume: 11
Serial Issue: 2
Title: Exploration for Zn-rich mineralization in the semi-arid Cobar region of NSW, Australia
Affiliation: Australian National University, Research School of Earth Sciences, Canberra, A.C.T., Australia
Pages: 93-101
Published: 201105
Text Language: English
Publisher: Geological Society Publishing House, London, United Kingdom
References: 24
Accession Number: 2011-052144
Categories: General geochemistryEconomic geology, geology of ore deposits
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 8 tables, sketch maps
S31°30'00" - S31°30'00", E145°49'00" - E145°49'00"
Secondary Affiliation: Minerals and Metals Group, AUS, Australia
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 201129
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