Dispersion of gold in stream sediments in the Sungai Kuli region, Sabah, Malaysia
Dispersion of gold in stream sediments in the Sungai Kuli region, Sabah, Malaysia (in The 20th IGES; proceedings, Anonymous)
Geochemistry - Exploration, Environment, Analysis (February 2003) 3, Part 1: 51-56
The distribution of Au has been investigated under tropical rainforest conditions in an Au-rich tributary of the Sungai Kuamut, Sabah, Malaysia. Paired high- and low-energy sediment samples were collected, before disturbance by logging, from gravel and cobble sites on bars and riffles. Gold content of five size fractions finer than 212 mu m was determined by fire-assay atomic absorption spectrometry (FA-AAS). Use of a bulk leach cyanidation (BLC) procedure for Au was also tested. A strong, but extremely erratic, Au anomaly is present in the sand-size fractions. The highest Au values are found in gravel environments and concentrations decrease with decreasing grain size to a minimum in the -53 mu m fraction. To maintain anomaly contrast while minimizing the chance of missing the erratic Au anomalies, use of the -105 mu m fraction is recommended for stream sediment exploration surveys in the region. Because of the abundance and low Au content of the -53 mu m fraction, increased erosion and additional inputs of this fraction into the stream after logging activity could significantly dilute the Au anomaly.