Gravity Concentration in Artisanal Gold Mining

Abstract

Worldwide there are over 43 million artisanal miners in virtually all developing countries extracting at least 30 different minerals. Gold, due to its increasing value, is the main mineral extracted by at least half of these miners. The large majority use amalgamation either as the final process to extract gold from gravity concentrates or from the whole ore. This latter method has been causing large losses of mercury to the environment and the most relevant world’s mercury pollution. For years, international agencies and researchers have been promoting gravity concentration methods as a way to eventually avoid the use of mercury or to reduce the mass of material to be amalgamated. This article reviews typical gravity concentration methods used by artisanal miners in developing countries, based on numerous field trips of the authors to more than 35 countries where artisanal gold mining is common.

Water footprint in gold extraction: A case-study in Suárez, Cauca, Colombia

“…In the inventory of mineral processing plants, 24 plants or processing sites were identified, of which 19 correspond to plants located in the primary deposits and 6 are sites of alluvial mineral exploitation (Table 1). It should be noted that 12 processing plants were based exclusively on the gravimetric recovery of gold (gravity separation primarily due to weight and size differences between different particles, separated by panning, sluicing or tabling [28]) 4 plants used amalgamation and 4 cyanidation.…”

Edukasi Teknik Penambangan Emas yang Ramah Lingkungan pada Tambang Rakyat Skala Kecil di Daerah Soripesa, Kecamatan Wawo, Kabupaten Bima, Nusa Tenggara Barat

“…Pada tahapan ini, seorang penambang harus lebih ekstra hati-hati karena pada tahapan ini sudah mulai berinteraksi dengan bahan kimia yaitu larutan air raksa (merkuri). Larutan air raksa adalah salah satu logam berat yang biasa digunakan untuk memisahkan bijih emas dengan mineral lain atau pengotornya (Clarkson et al, 2017;Veiga & Gunson, 2020). Umumnya para penambang emas tradisional termasuk yang ada di daerah Soripesa, Kabupaten Bima, Provinsi NTB, tidak mempunyai pengetahuan mengenai cara penggunaan yang benar dan formulasi yang tepat dalam penggunaan larutan tersebut.…”

Caracterização de minério de ouro aluvionar com o uso do concentrador Falcon

“…Devido às restrições operacionais no garimpo, optou-se por fazer a classificação do material por meio do peneiramento a fim de obter a especificação granulométrica limite para a operação do concentrador gravimétrico Falcon, além da importância da classificação, por peneiramento ou hidrociclone, para qualquer tipo de concentração gravítica, o que pode prejudicar a recuperação de ouro no garimpo caso não seja feito [10]. O material passante da primeira peneira de 1700 µm seguiu para a primeira etapa no concentrador Falcon, respeitando o seu limite superior para operação em escala laboratorial.…”