Mineralogy of the Mount Pleasant tin deposit in New Brunswick

Abstract

The Mount Pleasant tin deposit in New Brunswick is unusually complex and contains a wide variety of minerals. The tin-bearing minerals are cassiterite and stannite. Cassiterite is the chief tin mineral and it occurs as disseminations in mineralized rock fluorite masses and sulphide veins. The cassiterite in the mineralized rock and sulphide veins occurs as small grains, whereas that in the fluorite masses is present as relatively large grains. Stannite was found mainly as irregular grains and minute inclusions in sphalerite and arsenopyrite. Sphaltt rite is the most abundant ore mineral. It is generally black and contains minute exsolution bodies of chalcopyrite, stannite and pyrrhotite. Analyses of sphalerite concentrates give Zn 45.0 to 48.90%, Fe 7.8 to 13.1%, Cu 1.3 to 5.2%, Sn 0.14 to 0.38%, In 0.03 to 0.30%, Cd 0.1 2 to 0.18%,and Mn. 0.06 to 0.08%. Other minerals in the deposit are: rutile, wolfrarnite, scheelite, hematite, chalcocite, tennantite, covellite, galena, molybdenite, bismuthinite; wittichenite, a\rsenopyrite, glaucoclot, pyrite, marcasite, pyrrhotite, native bismuth, native gold, quartz, feldspar, topaz, zircon, siderite, calcite, fluorite, biotite, sericite, chlorite, kaolinite, dickite, hydrornica, goethite, scorodite, arseno-bismite, and malachite. Sphalerite geothermornetry indicates that the depositional temperatures of sphalerite fall between 335°C and 700°C, and arsenopyrite geothermornetry gives depositional temperatures up to 500 °C.

The first discovery of mawsonite and other Cu-Fe-Sn sulfides in gold-sulfide-quartz ores

“…5; Fe, 6.4; Zn, 7.7; Sn, 22.6; S, 29.5; total 100. 7 wt %, formula Cu 2.35 Fe 0.49 Sn 0.82 S 3.97 ) ( Petruk, 1973) is also different from our mineral.…”

“…The R values for the minerals are given in Table 2, and the reflection spectra are shown in Figure 4. An analysis of the results and their comparison with the literature data for Cu-Fe-Sn sulfides (Levy, 1967;Kachalovskaya et al, 1973;Petruk, 1973) have shown that on the basis of optical pro perties, our mawsonite is most similar to that from Mt. Lyell (Levy, 1967).…”

“…The mineral Cu 3 SnS 4 is char acterized by a spectral with gentler slope than in stannite, and higher R values as compared with koesterite. In optical properties, the min eral Cu 3 SnS 4 is extremely close to an unnamed mineral, described by Petruk (1973), although their compositions differ markedly.…”

Mineral/water interactions in tailings from a tungsten mine, Mount Pleasant, New Brunswick

“…3). 2472 B. M. Petrunic and T. A. Al Although arsenopyrite is the only sulfide mineral that was found in abundance, other sulfides are known to occur in the deposit (Petruk, 1964;Parrish, 1977) and are almost certainly present in the tailings. The lower boundary of the oxidation zone can be defined at a depth of ϳ0.6 m on the basis of sulfate concentrations, consistent with hydrological measurements that suggest that the unsaturated zone extends to an average depth of 0.4 m. At depth, the pore-water pH increases to values between 8.7 and 10.7, and the concentrations of SO 4 , As, and most metals (excluding W) decrease correspondingly (Fig.…”

“…Numerous papers have discussed the geology and mineralogy of the Mount Pleasant deposits (Black, 1961;Petruk, 1964;Parrish, 1977;Atkinson et al, 1981;McCutcheon, 1990;Sinclair and Kooiman, 1990). In general, the W-Mo deposits at Mount Pleasant are associated with intrusive rocks, particularly granites (McCutcheon et al, 2001).…”