کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4457253 1312600 2014 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Geochemistry and mineralogy of mine-waste material from a “skarn-type” deposit in central Mexico: Modeling geochemical controls of metals in the surface environment
ترجمه فارسی عنوان
ژئوشیمی و کانی شناسی مواد زائد معدنی از یک "اسکارن تای" سپرده مرکزی مکزیک: مدلسازی کنترلهای ژئوشیمیایی فلزات در محیط سطح
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی اقتصادی
چکیده انگلیسی


• Mineralogy and chemical concentration of metals in mine tailings at central Mexico was analyzed.
• Sequential extractions on samples were carried on to determine the mineral phases hosting metals.
• The tailings contains considerable amounts of As, Fe, Pb, Zn, and Cu, in different minerals phases.
• Primary minerals (eg pyrite and As-pyrite) rapidly oxidize to Fe-oxi-hydroxides and sulfo-salts.
• Redox conditions for the dissolution-precipitation controls of metals was modeled with GWB.

Several metal sulfide ore deposits (epithermal veins and skarn-type deposits) occur in the central east portion of Mexico (Sierra Madre Oriental). Historically, some of these deposits have been exploited since the 1500s and 1600s. Currently, there are millions of tons of mine waste materials with high content of potentially toxic heavy metals. This work focuses on geochemistry and mineralogy and modeling of redox and acid–base reactions of mine waste material from the Xichú mining area (Aurora Mine), Guanajuato state. The processed ore material at Xichú (circa 1 million tons) consisted of pyrite, arsenopyrite, galena, sphalerite, chalcopyrite, and minerals with Ag and some Au. The mine waste material contains considerable amounts of As, Fe, Pb, Zn, and Cu, in different mineral phases mostly, Fe-oxides and oxyhydroxides, sulfo-salts and traces of primary sulfides. Potential metal liberation and mobility pose a threat to the local population. Redox reactions locally produce pH around 2 in leachates with high metal content. Secondary mineralogy includes goethite, hematite, ferrihydrite, jarosite group minerals, gypsum and minor carbonates, among others. The geochemical dynamics is controlled by the seasonal rains (from June to September), along with high evaporation rates. These factors produce minor acid mine drainage and metal leaching. Redox and dissolution–precipitation reactions control the mobility of heavy metals into the surrounding environment. Arsenic and heavy metal content in tailings is up to 37% Fe, 62 gr/Kg of As, 2.4 gr/Kg of Cu, 13 gr/Kg of Zn and 17 gr/Kg of Pb. Sequential extraction experiments indicated that most of the As is bounded to Fe oxyhydroxides; Zn and Cu are mostly bounded to soluble phases and Pb is mostly bounded to sulfide. Mineralogical changes are controlled seasonally mainly by dissolution and precipitation of secondary phases: jarosite, gypsum, goethite and hematite and minor metal carbonates. Locally, some highly evaporated ponds have low pH (between 2 and 3) and very high concentrations of As and metals. The Geochemist's Workbench (Act2 module) software was used to model the redox conditions for the dissolution–precipitation reaction controlling liberation and mobility of As and metals into the environment. It seems that most of the As and metals are involved in a dissolution–precipitation cycle in the tailings piles and very few are released into the environment.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Geochemical Exploration - Volume 144, Part A, September 2014, Pages 28–36
نویسندگان
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