Phytomining for Artisanal Gold Mine Tailings Management

Abstract

Abstract:Mine tailings are generally disposed of by artisanal and small scale gold miners in poorly constructed containment areas and this leads to environmental risk. Gold phytomining could be a possible option for tailings management at artisanal and small-scale gold mining (ASGM) locations where plants accumulate residual gold in their above ground biomass. The value of metal recovered from plants could offset some of the costs of environmental management. Getting gold into plants has been repeatedly demonstrated by many research groups; however, a simple working technology to get gold out of plants is less well described. A field experiment to assess the relevance of the technology to artisanal miners was conducted in Central Lombok, Indonesia between April and June 2015. Tobacco was planted in cyanidation tailings (1 mg/kg gold) and grown for 2.5 months before the entire plot area was irrigated with NaCN to induce metal uptake. Biomass was then harvested (100 kg), air dried, and ashed by miners in equipment currently used to ash activated carbon at the end of a cyanide leach circuit. Borax and silver as a collector metal were added to the tobacco ash and smelted at high temperature to extract metals from the ash. The mass of the final bullion (39 g) was greater than the mass of silver used as a collector (31 g), indicating recovery of metals from the biomass through the smelt process. The gold yield of this trial was low (1.2 mg/kg dry weight biomass concentration), indicating that considerable work must still be done to optimise valuable metal recovery by plants at the field scale. However, the described method to process the biomass was technically feasible, and represents a valid technique that artisanal and small-scale gold miners are willing to adopt if the economic case is good.

Future direction of Au agromining on how to solve artisanal and small scale gold mining problems

“…Artisanal and Small Scale Gold Mining (ASGM) is a term for informal Au mining by traditional technologies. This method can be carrying out by individual, groups or families (Krisnayanti et al, 2012;Krisnayanti, 2018;Puluhulawa and Harun, 2019). The stages of ASGM consist of amalgamation, tailings processing and gold recovery.…”

“…Besides that, several ex ASGM lands have been converted to cropland without remediation of Hg and CN that be released from amalgamation and cyanidation. The concentration of Hg within the soil of that land reaches 8,364 ppm (Krisnayanti, 2018).…”

“…ASGM is an attractive alternative livelihood for rural workers because it has good potential to improve the wealth of a community. In general, ASGM has increased income and the availability of employment opportunities (Krisnayanti, 2018;Owusu et al, 2019). Therefore, ASGM should be regulated in such a way that regulations and policies are oriented towards environmental sustainability and public health.…”

Kandungan Logam Berat (Hg dan Mn) Pada Pilsbryoconcha exilis dan Sedimen yang Terdapat di Sungai Pelangan, Lombok Barat

“…PENDAHULUAN Nusa Tenggara Barat merupakan salah satu provinsi yang memiliki potensi alam di berbagai bidang diantaranya pertanian, kelautan, kehutanan, dan pertambangan (Krisnayanti et al, 2013). Potensi alam Nusa Tenggara Barat yang mempunyai nilai ekonomi tinggi berasal dari hasil pertambangan yaitu berupa emas.…”

“…Kegiatan penambangan yang ada di daerah tersebut merupakan penambangan emas skala kecil (artisenal gold mining) yang pada umumnya dimiliki oleh sebuah kelompok penambang maupun masyarakat umum. Menurut Krisnayanti et al, (2013) bahwa aktivitas penambangan emas skala kecil yang ada di Kecamatan Sekotong dimulai pada pertengahan tahun 2008.…”