Search CRC LEME :

powered by FreeFind

Publication Policy

Open File Report Series

OFRS Index


Regolith Maps

Annual Reports

Articles & Papers


Minerals Briefs

"Focus on Salt"

Other LEME Reports

Order Form

Open File Report 107

Selective and partial extraction analyses of transported overburden for exploration in the Yilgarn Craton and its margins

Gray, D.J., Wildman, J.E. and Longman, G.D.

Seven sites from across the Yilgarn Craton and the northern Proterozoic margin were selected to test the utility of partial extractions for exploration for buried mineralization. The techniques used were selective extractions for carbonates, Mn oxides and amorphous Fe, varying HCl treatments, the CSIRO iodide extraction for Au, mobile metal ions (MMI) and enzyme leach. The selective extractions work consistently and give good correlations with the HCl digests. The MMI method involves two separate extractions: the first, for Cd, Cu. Pb and Zn, gave results that are similar, in terms of comparison between samples at each site, to HCl and selective extractions; whereas the second extraction, for Ag, Au, Co, Ni and Pd. commonly dissolves all of the extractable Au and Ag (commonly 70-80% of the total Au, and closely correlated with total, iodide and HCl soluble extractions). Therefore, the MMI extraction does not appear to be giving any additional information for Au or Ag than can not be obtained using standard analyses. The enzyme leach reagent is targeted at an 'amorphous' Mn phase, though the proportion of the Mn dissolved (< 0.5 to 20%) varies dramatically between sites. The enzyme leach method also appears to give unique results, not correlated with other methods, and gives a much larger range of elements than MMI. However, Cs, Fe, Ga, Hf. La, Li, Nb, rare earth elements, Pb, Sc, Sn, Th, Ti and Zr show very close linear correlations, suggesting either a highly specific interaction between these elements and Fe or an analytical interference from Fe

The extraction results for the soil traverses indicate that soil is a successful exploration medium only where the transported overburden in thin (<10 m), as at Safari and in restricted areas at Baxter and Fender, and that Au, for a number of methods, is by far the best target element. Use of partial extractions gave a number of strong false positives and/or very poor ability for the extraction methods to shows buried mineralization, except where total extractions would work anyway. Even at those sites where Au successfully delineates mineralization, partial extraction methods for the other elements are unsuccessful.

Last updated: Sunday, August 05, 2001 14:02:36


Cooperative Research Centres Australia

About Us | News & Events | Research
Publications | Education | Staff Only | Links

Contact Us | Disclaimer | Sitemap
© CRC LEME 2004

CRC LEME is established and supported under the Australian Government's Cooperative Research Centres Program. The CRC Program is an Australian Government initiative which brings together research groups with common interests.

CRC LEME Core Parties