Mineralogical and geochemical investigations of silicate-rich mine waste from a kyanite mine in central Virginia: implications for mine waste recycling

Abstract

A kyanite mine in central Virginia produces a silicate-rich waste stream which accumulates at a rate of 450,000-600,000 tons per year. An estimated 27 million tons of this waste stream has accumulated over the past 60 years. Grain size distribution varies between 1.000 and 0.053 mm, and is commonly bimodal with modes typically being 0.425 and 0.250 mm and uniformity coefficients vary from 2.000 to 2.333. Hydraulic conductivity values vary from 0.017 to 0.047 cm/s. Mineralogy of the waste stream consists of quartz, muscovite, kyanite and hematite. Muscovite grains have distinct chemical compositions with significant Na 2 O content (1.12-2.66 wt%), TiO 2 content (0.63-1.68 wt% TiO 2 ) and Fe content, expressed as Fe 2 O 3 (up to 1.37 wt%). Major element compositions of samples were dominated by SiO 2 (87.894-90.997 wt%), Al 2 O 3 (6.759-7.741 wt%), Fe 2 O 3 (1.136-1.283 wt%), and K 2 O (0.369-0.606 wt%) with other components being \1.000 wt%. Elements of environmental concern (V, Cr, Ni, Cu, Zn, As, Ag, Sn, Sb, Ba, Hg, Tl, and Pb) were detected; however, the concentrations of all elements except Ni were below that of the kyanite quartzites in the region from which the waste is derived. Both major and trace element compositions indicate minimal variation in composition. The waste stream has potential for recycling. Muscovite is suitable for recycling as a paint pigment or other industrial applications. Muscovite and hematite are commonly intergrown and are interpreted to be material where much of the elements of environmental concern are concentrated. Reprocessing of the waste stream to separate muscovite from other components may enable the waste stream to be used as constructed wetland media for Virginia and nearby states. Recycling of this mine waste may have a positive impact on the local economy of Buckingham County and aid in mitigation of wetland loss.

Implementation of Flotation to Recover Lead and Barite From Komsheche Mine Jig Tailings

“…Due to the increasing demand, the reduction of mineral resources and adoption of strict environmental laws around the world, recycling is an important issue for societies (Valero et al, 2010). The tailings from the mineral processing plants are normally to be considered as low-grade deposits, the recycling and reuse of these tailings would be an effective approach and, in many cases economically attractive to reduce the environmental im-pact, especially to minimize the environment pollution around the mine, in addition to having economic benefits (Geise et al, 2011;Edraki et al, 2014;Broadhurst et al, 2015;Asghari et al, 2018). One of the possible ways to achieve cost-effective production is to recover barite from waste materials/tailings.…”

Characterization and Beneficiation Options for Tungsten Recovery from Yxsjöberg Historical Ore Tailings

“…In addition to tungsten, other elements of economic importance and with elevated concentrations in the tailings under study include copper (Cu), fluorspar (CaF 2 ), sulphur (S), tin (Sn), zinc (Zn), beryllium (Be), and bismuth (Bi) [20]. Eventual extraction of these elements and safe disposal of the remaining residue require a detailed understanding of the mineralogical, geochemical, and bulk physical properties of the tailings [7,21]. Preliminary mineralogical and geochemical studies of the tailings revealed that W, Cu, F, S, Sn, Zn, Be, and Bi are hosted mainly in scheelite, chalcopyrite, fluorspar, pyrrhotite, cassiterite, danalite (both Zn and Be), and bismuthinite, respectively [20].…”