Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador
Mercury is a highly toxic pollutant that can negatively affect human health and the environment; informal mining is one of the main sources of anthropogenic mercury release due to the separation or concentration by amalgamation that is still used to recover gold directly from ore. In the Nambija min...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-10-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/13/11/1396 |
| _version_ | 1797458245514690560 |
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| author | Richard González-Vásquez María Jesús García-Martínez David Bolonio |
| author_facet | Richard González-Vásquez María Jesús García-Martínez David Bolonio |
| author_sort | Richard González-Vásquez |
| collection | DOAJ |
| description | Mercury is a highly toxic pollutant that can negatively affect human health and the environment; informal mining is one of the main sources of anthropogenic mercury release due to the separation or concentration by amalgamation that is still used to recover gold directly from ore. In the Nambija mining district, there is still informal mining based on practically no technical knowledge, which uses amalgamation as a processing technique for gold recovery. The production tasks that directly affect the handling of mercury during the in situ grinding–amalgamation process are monitored here. Experimental grinding tests were initially carried out in a “chancha” bar mill for a range of ore sizes and as a function of time; then, experimental tests were performed at the macro-level on grinding cycles in Chilean mills. Considering the characteristics of the ore mineral and the operation of the Chilean mills, it was determined that it is possible to reduce the Hg input to mill by up to 20% (at source). Experimental grinding–amalgamation tests were carried out at different times along with a grain size analysis of the ore; the recovery establishes the grinding time and the fraction in which the gold is extracted in a greater proportion, which affects the control of the amalgamation times. The mercury dosage used by the miners in the amalgamation process should be reduced, considering trials where there is better gold recovery and with the purpose of also reducing mercury losses; eventually, it is possible to jointly achieve an increase in gold recovery. |
| first_indexed | 2024-03-09T16:35:14Z |
| format | Article |
| id | doaj.art-74448d09dbfe4eb0b0cfebb9aac88353 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T16:35:14Z |
| publishDate | 2023-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-74448d09dbfe4eb0b0cfebb9aac883532023-11-24T14:57:32ZengMDPI AGMinerals2075-163X2023-10-011311139610.3390/min13111396Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, EcuadorRichard González-Vásquez0María Jesús García-Martínez1David Bolonio2Energy and Fuels Department, Escuela Técnica Superior de Ingenieros de Minas y Energía, Universidad Politécnica de Madrid, C. de Ríos Rosas 21, 28003 Madrid, SpainEnergy and Fuels Department, Escuela Técnica Superior de Ingenieros de Minas y Energía, Universidad Politécnica de Madrid, C. de Ríos Rosas 21, 28003 Madrid, SpainEnergy and Fuels Department, Escuela Técnica Superior de Ingenieros de Minas y Energía, Universidad Politécnica de Madrid, C. de Ríos Rosas 21, 28003 Madrid, SpainMercury is a highly toxic pollutant that can negatively affect human health and the environment; informal mining is one of the main sources of anthropogenic mercury release due to the separation or concentration by amalgamation that is still used to recover gold directly from ore. In the Nambija mining district, there is still informal mining based on practically no technical knowledge, which uses amalgamation as a processing technique for gold recovery. The production tasks that directly affect the handling of mercury during the in situ grinding–amalgamation process are monitored here. Experimental grinding tests were initially carried out in a “chancha” bar mill for a range of ore sizes and as a function of time; then, experimental tests were performed at the macro-level on grinding cycles in Chilean mills. Considering the characteristics of the ore mineral and the operation of the Chilean mills, it was determined that it is possible to reduce the Hg input to mill by up to 20% (at source). Experimental grinding–amalgamation tests were carried out at different times along with a grain size analysis of the ore; the recovery establishes the grinding time and the fraction in which the gold is extracted in a greater proportion, which affects the control of the amalgamation times. The mercury dosage used by the miners in the amalgamation process should be reduced, considering trials where there is better gold recovery and with the purpose of also reducing mercury losses; eventually, it is possible to jointly achieve an increase in gold recovery.https://www.mdpi.com/2075-163X/13/11/1396artisanal miningmercurygrindingamalgamationgrain size testsoptimization |
| spellingShingle | Richard González-Vásquez María Jesús García-Martínez David Bolonio Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador Minerals artisanal mining mercury grinding amalgamation grain size tests optimization |
| title | Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador |
| title_full | Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador |
| title_fullStr | Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador |
| title_full_unstemmed | Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador |
| title_short | Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador |
| title_sort | investigation of gold recovery and mercury losses in whole ore amalgamation artisanal gold mining in nambija ecuador |
| topic | artisanal mining mercury grinding amalgamation grain size tests optimization |
| url | https://www.mdpi.com/2075-163X/13/11/1396 |
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