Mineralogy of the pollutant products formed in the Masca exploration area (Lower Iara Valley Basin, Cluj County, Romania)

Abstract

ABSTRACT. In the present study the mineralogy of a tailing dam situated in the Maşca mining area is discussed. Our aim was to point out the physicochemical processes, which occur under the action of the exogenous factors. The studied samples were collected from different levels of the dam wall, from the Maşca mine and Iara river waters. The applied analytical methods are: transmission polarized microscopy, transmission electron microscopy, X-ray diffractometry, and atomic absorption spectrometry. The physicochemical parameters have been measured in situ and in the laboratory.The minerals present in the tailings are represented by: garnets (andraditegrossular and almandine series), diopside, hedenbergite, actinolite, tremolite, epidote, zoisite, biotite, phlogopite, serpentine minerals, chlorite, tourmaline, quartz, feldspar, anatase, apatite and opaque minerals (pyrrhotite, pyrite, magnetite and hematite). The carbonate minerals belonging to the mining waste are represented mostly by dolomite and subordinately by calcite. The identified neoformation minerals formed as a result of the action of the exogenous factors are the following: illite, illite/smectite, nontronite, palygorskite, chlorite-vermiculite, gypsum, epsomite, hexahydrite, wattevillite, ferrohexahydrite, hallotrichite, bilinite(?), goethite and amorphous iron hydroxide.The ) contents, exceeding international and national guidelines. Although the pH of the streams originating from the mine area vary between neutral to slightly alkaline, pollution occurs and significantly impacts the mineralized area as well as the neighboring areas.

Immobilization of Potentially Toxic Elements in Contaminated Soils Using Thermally Treated Natural Zeolite

“…Lower Iara Valley Basin is known for its deposit of magnetite mineralization associated with garnet and pyroxene skarns, limestone, and metalliferous deposits rich in precious metals [ 19 ]. Due to legacy mining, there are several tailing deposits containing silicates in this area (garnets, pyroxenes, amphiboles, etc.…”

“…Due to legacy mining, there are several tailing deposits containing silicates in this area (garnets, pyroxenes, amphiboles, etc. ), carbonates (dolomite and subordinately calcite) and metallic minerals (sulfides and oxides) [ 19 ]. Weathering processes favors the oxidation–hydration of minerals from tailings leading to the pollution of the environment.…”