Environmental impacts associated with the mining of carbonatite deposits are an emerging concern due to the demand for critical metals. This study investigates the chemistry of tailings seepage at the former Saint Lawrence Columbium mine near Oka, Québec,Canada, which produced pyrochlore concentrate and ferroniobium from a carbonatite-hosted Nb-REE deposit. Its objectives are to characterize the mineralogy of the tailings and their pore water and effluent chemistries. Geochemical mass balance modeling, constrained by aqueous speciation modeling andmineralogy, is then used to identify reactions controlling the chemical evolution of pore water along its flow path through the tailings impoundment. The tailings are composed mainly of REE-enriched calcite (82 wt. %), biotite (12 wt. %) and fluorapatite (4 wt. %). Minor minerals includechlorite, pyrite, sphalerite, molybdenite and unrecovered pyrochlore. Secondary minerals include gypsum, barite and strontianite. Within the unsaturated zone, pore water chemistry is controlled by sulfide oxidation and calcite dissolution with acid neutralization. With increasing depth below thewater table, pore water composition reflects gypsum dissolution followed by sulfate reduction and FeS precipitation driven by the oxidation of organic carbon in the tailings. Concomitantly, incongruent dissolution of biotite and chlorite releases K, Mg, Fe, Mn, Ba and F, forming kaolinite andCa-smectite. Cation exchange reactions further remove Ca from solution, increasing concentrations of Na and K. Fluoride concentrations reach 23 mg/L and 8 mg/L in tailings pore water and effluent, respectively. At a pH of 8.3, Mo is highly mobile and reaches an average concentration of 83 µg/Lin tailings effluent. Although U also forms mobile complexes, concentrations do not exceed 16 µg/L due to the low solubility of its pyrochlore host. Adsorption and the low solubility of pyrochlore limit concentrations of Nb to less than 49 µg/L. Cerium, from calcite dissolution, isstrongly adsorbed although it reaches concentrations (unfiltered) in excess of 1 mg/L and 100 µg/L in pore water and effluent, respectively. Mine tailings from carbonatite deposits are enriched in a variety of incompatible elements with mineral hosts of varying reactivity. Some of theseelements, such as F and Mo, may represent contaminants of concern because of their mobility in alkaline tailings waters.

Epidote from detrital sediments derived from propylitic alteration associated with porphyry copper mineralization could be used as a vector for mineral exploration in drift-covered areas; however, differentiating porphyry-related epidote from other sources is crucial. We analyzed the composition of epidote from granitoids associated with porphyry copper mineralization, Nicola Group rocks and grains from till at three sites (Gibraltar, Mount Polley, and Woodjam) within British Columbia's Quesnel terrane, where two main sources of epidote in till are propylitic-altered rocks associated with porphyry mineralization and metamorphosed Nicola Group mafic volcanic and sedimentary rocks. Although principal component analysis was insufficient to distinguish between intrusive- and metamorphic-related epidote, patterns in the abundance of sets of elements indicate provenance. Epidote from granitoids typically has less Hf+Th (<6 ppm) and Sc+Cr+Y (<100 ppm) compared to epidote from Nicola Group rocks; abundances of As and Sb (>>4 ppm As and >>0.6 ppm Sb) in epidote derived from hydrothermal alteration zones associated with porphyry copper mineralization exceed levels measured in metamorphic epidote; and elevated Cu (approximately >30 ppm) in epidote can indicate copper mineralization. These trends in the chemical composition of till-derived epidote can be used in mineral exploration to detect buried hydrothermal alteration associated with porphyry copper mineralization.

Small, low-grade, granitic pegmatite U-Th-REE deposits are found throughout the Grenville geological province of eastern Canada. Groundwater quality at historical mining properties in the Bancroft area was investigated in order to better understand the mobility of trace elements that may pose health risks if there is renewed development of this class of mineral deposit. Groundwater samples were obtained from diamond drill holes, flowing adits and flooded mine shafts. Uranium occurs almost entirely in the dissolved (<0.45 mu m) phase and is found at concentrations reaching 2579 mu g/L. The Canadian maximum acceptable concentration for U in drinking water (0.02 mg/L) was exceeded in 70% of samples. Regulatory limits for Ra-226 (0.5 Bq/L) and for Pb-210 (0.2 Bq/L) were generally exceeded in these samples as well. Speciation modeling indicates that over 98% of dissolved U is in the form of highly mobile uranyl-Ca-carbonate complexes known to inhibit U adsorption. Uranium concentrations in groundwater appear to be correlated with the uranothorite content of the deposits rather than with their U grade. Uranothorite may be more soluble than uraninite, the other ore mineral, because of its non-ideal composition and metamict structure. Thorium, released concomitantly with U during the dissolution of uranothorite and thorian uraninite, exhibits median and maximum total concentrations of only 0.1 and 11 mu g/L, respectively. Mass balance and stoichiometric considerations indicate that almost all Th is immobilized very close to its source. The sums of total light REE (La-Gd) concentrations have median and maximum values of 6 and 117 mu g/L, respectively. The sums of total heavy REE (Tb-Lu) concentrations have median and maximum values of 0.8 and 21 mu g/L, respectively. Light REE are derived mainly from the dissolution of metamict allanite whereas the sources of heavy REE are widely dispersed among accessory minerals. Fractionation patterns of REE in the dissolved phase are flat or concave, with negative Ce anomalies associated with more oxic groundwaters. The data suggest preferential LREE and HREE complexation with organic and carbonate ligands in the dissolved phase, respectively. Fractionation patterns in the suspended particulate phase exhibit decreasing enrichment with atomic number from La to Gd and a flat profile from Tb to Lu. This is explained by preferential sorption of LREE and uniform sorption of HREE. Manganese particulates are the most likely sorbents. Potential health risks from Th or REE in mine waters are unlikely due to the very low mobility of these elements. Uranium, on the other hand, exhibits high mobility in shallow, oxic groundwaters and drainage from some mine adits may require mitigation. Crown Copyright (C) 2016 Published by Elsevier Ltd. All rights reserved.

Introduction: Primitive ordinary chondrites potentially contain valuable information about the early Solar System, and are used e.g. in studies of pre-solar grains, the age of chondrule formation, and the age of chondrite equilibration. But documentation of their detailed petrography may be lacking, even though sophisticated chemical and isotopic analyses have been obtained. While documenting and classifying an Antarctic chondrite with low metal and well-defined chondrules [1],[2], we have examined a comparable meteorite, Saratov. Its classification is L4 whereas the other is an L/LL3, probably of grade 3.5 to 3.6 [2]. Saratov fell September 6, 1918, total known weight (TKW) 328 kilograms [3]. To date we have been unsuccessful in discovering a detailed description of its mineralogy and texture although it has been analyzed in some important studies [4],[5],[6], and is widely available in collections and from dealers. Our study adds important information on Saratov. The Antarctic meteorite was found about a decade ago, TKW 2.3 kilograms. Sample Character: Both meteorites contain an abundance of chondrules, ranging in size from less than a mm. to over a cm. Both are friable, and chondrules are easily detached from samples. Both consist of chondrules and chondrule fragments or agglomerations, matrix, and metal (mainly troilite and FeNi phases) and show a low shock stage (S1-S2) although the L/LL3 may have undergone minor brecciation or even melting. It is moderately weathered. Polished Thin Section (PTS) Studies: Methodology: As described previously [2] polished thin sections were systematically documented by colour photomicrographs and mapping in back-scattered electron (BSE) mode with a scanning-electron microscope (SEM). All images were digitized. The mosaic of BSE images, all at the same magnification, were compiled into single large photomosaic maps of the sections. Adjustment of the contrast among adjacent BSE images resulted in virtually seamless maps that show the sections in great detail, and serve to locate areas of investigation at higher magnification. Two polished thin sections of the Antarctic find were available, and one PTS and a thin section of Saratov. The mineralogy and