Illegal mining operations in Indonesia cost the country $6.1B per year in lost tax revenues and license fees. The Indonesia Police Laboratory (Puslabfor) uses HDXRF technology in forensic investigations targeting unlicensed gold, silver and other precious metal mining on public and private lands. Over the past 2 years, hundreds of rock, soil and sludge samples from over a dozen potential sites have been surveyed to identify precious metal and other elemental content. Using this new forensic tool, Puslabfor can link seized materials to specific mining sites making it easier to disrupt illegal mining.
Forensic investigations for illegal mining require on-site sampling across many sites to find geographic matches with seized samples and processed materials. Traditional testing methods, like wet chemistry, require highly trained specialists and can be very costly. Outsourcing samples to a lab is not ideal due to long turnaround time which delays the investigation, high cost, and logistical issues like breaking the chain of custody for evidence.
Using HDXRF, Puslabfor is able to quantify the elemental composition of samples on-site, making it possible to quickly survey and discover links between field measurements and pre-measured contraband. The precision of the HDXRF measurement provides reliable ratios of elemental content that can be used as signatures for matching and identification purposes. Compared to traditional wet chemistry testing, HDXRF is much faster, more cost-effective, more efficient, safer and as reliable. Which is why many prefer HDXRF analysis, especially when working with dozens of samples that make lab-based measurements labor intensive and cost-prohibitive. HDXRF instruments are also very easy to use and do not require highly trained professionals to operate, allowing officers in the field with minimal training to produce court ready results.
||ND < 155
||ND < 118
||ND < 56
||ND < 48
||ND < 73
||ND < 21
||ND < 55
||ND < 67
Table 1 shows measurements of investigated samples using HDXRF to identify the precious metal content (Au, Ag, Cu) and lead and mercury contaminants. Sample A is from raw material that has been processed to concentrate the gold and heavier elements, typically by panning or sluicing, before the mercury-based refining process. Sample B shows substantially higher concentrations of gold compared to Sample A, with heavy mercury content from in-the-field refining operations. Sample C is from remelted jewelry based on the high purity of the gold, and lack of contaminating elements.
hot spots in Indonesia
for illegal mining**
HDXRF technology has also been used to assess the environmental impact of illegal mining operations. With tailings containing elevated levels of Arsenic and Mercury, the legacy of site contamination from illegal mining activity will linger long after the miners have moved on to other sites. With ASTM D8064-16, HDXRF can be used to quantify heavy metal contamination in soil and sediment with levels of detection as low as 1 mg/kg.
“HDXRF is much
easier and a simpler
testing method than
- Mrs. Astarini Endah,
Chemical Sub Department Head
Gold Mining Losses:
Rp 80 trillion per year
Rocksand Powered by HDXRF
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*Illegal mining causing over Rp 80t in losses, TheJakartaPost
**The Toxic Toll of Indonesia’s Gold Mines, National Geographic