HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Webb, G. Articles by Fenstemaker, T. PubMed Articles by Webb, G. Articles by Fenstemaker, T. GeoRef GeoRef Citation Agricola Articles by Webb, G. Articles by Fenstemaker, T. Related Collections Mining Wastes Heavy Metals Soil Physics

ORIGINAL RESEARCH

Field-Scale Analysis of Flow Mechanisms in Highly Heterogeneous Mining Media

^a Dep. of Geological Sciences and Engineering, Univ. of Nevada, Reno, NV 89557
^b Thunder Mountain Gold, Elko, NV 89801, formerly Cortez Gold Mines
^c Dep. of Mining Engineering, Univ. of Nevada, Reno, NV 89557
^d current address, Dep. of Mining Engineering, Univ. of British Columbia, Vancouver, BC, Canada
^e School of Geology, Oklahoma State Univ., Stillwater, OK 74078
^f current address, Drumlin Energy Corp., Calgary, AB, Canada T2P 2Y3
^* Corresponding author (styler{at}unr.edu).

Received 10 July 2007.

A large-scale injection and tracer test was conducted in highly heterogeneous Au ore under typical mining practices of heap leaching. A total of 24 zero-tension lysimeters were installed beneath an active Au heap leaching operation and irrigated for 90 d with a cyanide solution. While rapid breakthrough of the wetting front suggesting preferential flow was observed in some lysimeters, the majority of the fluid flow did not follow preferential pathways. Rather, those lysimeters showing the most rapid breakthrough also showed the lowest steady-state drainage flux, suggesting that while rapid flow through the 6- to 8-m profile could occur, only a small percentage of the applied fluid volume was transmitted through these rapid pathways. Electrical resistivity imaging from the surface showed qualitatively good correlation between observed resistivity and the onset of drainage in adjacent lysimeters and also appeared to track the reaction of the infiltrating fluids with the carbonate ore and a lime amendment. The observation of limited preferential flow supports the empirical observations that heap leaching of Au ore with run-of-mine, end-dumped placed rock is a surprisingly efficient reactor in spite of the large heterogeneity inherent in these materials that would be expected to produce preferential flow.

Abbreviations: ERI, electrical resistivity imaging