Mineral Liberation Analyzer (MLA) is an automated mineralogical system originally developed to characterize ore and mill feeds for the metallurgical processing industry. Its ability to quantitatively characterize solid and particulate material, including whole rock thin sections, waste rock, tailings, soil, and sediments, has led to increasing applications in other industries. The software uses back-scatter electron imagery and energy dispersive X-ray analysis to analyze each particle’s shape, size, and mineralogical information. Energy dispersive X-ray data are compared to a user-generated Mineral Reference Library consisting of known phases and corresponding EDS spectra to classify each particle. MLA is used in this study to provide quantitative assessments of mining-related environmental samples to answer questions regarding mineralogical controls on bioaccessibility, metal leaching/acid rock drainage potential, and anthropogenic influence. Six tailings samples from the New Calumet Mine in Quebec, Canada, were analyzed using MLA. Gastric Pb bioaccessibility testing and total metal content performed on these samples indicated that Pb bioaccessibility in the <250 micron size fraction was not directly correlated with the total Pb concentration. This suggested that there were mineralogical and/or physical controls on bioaccessibility. MLA was used to quantify the relative proportions of cerussite, a highly bioaccessible Pb carbonate, and galena, a lower bioaccessibility Pb sulfide. Liberation and particle size were also analyzed as controls on bioaccessibility. Sample GD-VEG1 (highest bioaccessibility) has the highest ratio of cerussite to galena, the smallest particle size, and the most liberated Pb-bearing particles. The New Calumet tailings were also analyzed using static testing, a suite of laboratory tests used by environmental scientists and mine operators to operationally define acid rock drainage and metal leaching potential. Modal mineralogy obtained from MLA analysis was used to calculate neutralization potential (NP) and acid potential (AP), taking into account the presence of iron carbonate minerals and iron-bearing sulfides other than pyrite. Results are within several units of those obtained by static testing. Two Ni-impacted soil samples collected from the region of Kalgoorlie, Australia were characterized using MLA. Previous studies had focused on bioaccessibility and sequential extraction testing and minor mineralogical work. Preliminary XANES characterization conflicted with mineralogy predicted from sequential extraction and EMPA and MLA were used to quantitatively characterize major Ni-bearing phases and resolve previous discrepancies. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2013-08-24 08:13:18.722

Abandoned metal mines in the Tamar catchment, south west England, represent a significant threat to surface water quality via generation of acid mine waters. Currently the River Tamar fails environmental quality standards (EQS) established under the Water Framework Directive (2000/60/EC) for dissolved Cu (x ̅ = 0.19 ± 0.05 μmol L-1) and Zn (x ̅ = 0.19 ± 0.06 μmol L-1, both 1997-2007) downstream of historic mining area of Gunnislake. The aim of this study was to quantify the risk to surface water quality by diffuse drainage generated by mine waste tips. For the first time, a GIS model was compiled and used to generate a priority list of known areas of mine waste, based on physical and environmental factors. The methodology was consistent with European guidance documentation published to meet the requirements of the Mining Waste Directive (2001/21/EC) and has since been applied, in a modified form, to other catchments in south west England. Two study sites, with contrasting mineralogy and hydrology, scored highly in the model and were the subject of field investigations from 2007-2009. These were Devon Great Consols (DGC), an abandoned Cu-As mine near Gunnislake and Wheal Betsy (WB), an abandoned Pb-Ag mine, near Mary Tavy. At each site, surface waters and shallow groundwaters were sampled and analysed for dissolved metals (including Al, Cu, Zn, Mn, Pb, Ni, and Cd), metalloids (As, Sb), major ions and anions. Samples of four selected mine waste tips were also gathered and subjected to a range of laboratory leaching experiments including the novel application of a dynamic upflow percolation test, based on an existing European method (CEN TS 14405). Leachates generated by the waste tips in the field were highly variable and elevated with respect to EQS for Al (up to 1850 μmol L-1), Cu (570 μmol L-1), Zn (34 μmol L-1), Ni (3.8 μmol L-1), Cd (0.17 μmol L-1), Mn (216 μmol L-1), Fe(537 μmol L-1) , As (380 μmol L-1) and Sb (5.4 μmol L-1). Estimated annual fluxes of dissolved metals were predicted using average rainfall data and catchment areas calculated in ArcHydro9 to estimate the annual discharge of waters from the tip. These calculations showed annual contaminant flux from the tips to exceed, or be of the same order of magnitude to, major adit discharges in the catchment (e.g. Cu 50900-66900 mol y-1 at DGC and 470 mol y-1 Cd at WB) and represented a significant contributor to metal flux in the Tamar catchment. Primary sulphide minerals in the waste were generally highly altered and metals (Pb, Cu, Zn, and Mn) and As were found to be strongly associated with secondary iron minerals, precipitated under oxic conditions. In finer wastes, sorption to clay minerals was also found to be very important for the retention of dissolved metals, particularly Pb. Concentrations of contaminants in column field leachates were similar for most metals (Cu, Zn, Mn, Ni and Cd) and may provide a useful tool for prediction of leachate composition. However, sorption and release of metals and As to the secondary phases and clays were highly sensitive to pH change and where laboratory experiments did not replicate field pH, discrepancies between in situ and laboratory results were observed up to two orders of magnitude in scale (particularly for As and Pb).

<p>The municipality of Västervik, with support from Envipro Miljöteknik AB, is carrying out a main study of the minefields at Gladhammar. Mining of iron, copper and cobalt under different periods from the 16th century until the end of the 19th century has led to discharges of metals to the lakes situated downstream. The aim of the main study is to investigate the possibilities to reduce the environmental load on the surrounding ground and water caused by heavy metals from the mine. </p><p>The present report is a part of the main study. The aim of the work is to investigate the geochemistry of the groundwater. As a starting point, questions concerning affected areas, occurring metals and possible processes for propagation and limitation of the pollutants, have been posed. </p><p>The work is based on data from a pre-study and of the main study. In total, there are 25 groundwater pipes in the area. A subset of these pipes has been chosen in order to delimit the task at hand. The number of analysed measurements for each groundwater pipe range from five to 15. The data material has been compiled and subsequently evaluated with respect to natural background, variation in time, correlation with precipitation, depth and other measured parameters. Geochemical modelling using the computer code PHREEQC has also been conducted. </p><p>The waste of the minefields at Gladhammar is constituted of waste rock, slag and tailings. Arsenic, cobalt, copper, lead and zinc are the prevailing metals in the area. Iron, manganese and sulphur control the behaviour of heavy metals in water to a great extent and they have, as well as the prevailing metals, therefore been in focus for the study. </p><p>The data compilation shows that pipes in the proximity of slag and waste rock have the highest content of cobalt and copper. </p><p>The groundwater is affected, with respect to guideline-values, by, above all, cobalt and copper, but also to a certain extent by lead. The content of arsenic and zinc is classified as low to moderate. The groundwater is most affected in the areas of Holländarefältet and Torsfall. </p><p>The data analysis shows that out flush of secondarily retained metals is a likely pollutant process. Primarily, this is valid for cobalt and copper. The pollution propagation is likely limited by precipitation of secondarily minerals as well as adsorption to iron, manganese and aluminium particles. </p><p>The groundwater in the pipes close to waste rock and slag most certainly consists of surface water that runs off from the heaps on top of the hill. This is demonstrated by the high metal content of the surface run off. According to calculations on mixing, the groundwater at the shore is made up by a mixture of lake water and mine entrance water.</p>

No description available.

The integration of automated ore pre-concentration and waste disposal functions into the hard rock metal mining system, prior to treatment by conventional grinding and flotation, is proposed as a novel interpretation of Mine-Mill Integration for improving the economics and environmental impact of exploiting deep, low-grade or otherwise marginal mineral deposits. The proposed approach seeks to reject coarse, barren waste from the ore stream as early as possible in the mining cycle, and safely dispose of it as backfill underground. The concept is proposed as a Lean Manufacturing approach to hard rock mining, as an alternative to improving the economics of mining simply by increasing the mining rate. Lean Manufacturing philosophy seeks to design out overburden, smooth production, and eliminate waste from the system. It is suggested that the introduction of these systems into the hard rock mining process addresses all three of these areas of Lean thinking, and is thus an important approach to be considered for surface or underground mines wishing to simultaneously improve efficiency, economics and environmental performance, thus increasing the life, and the sustainability of the operation. The application of integrated mining, processing and waste disposal systems, where appropriate, is proposed as a strategy for the development of efficient new mining operations, or alternately the expansion of production at existing mines. Technologies specific to the success of the approach such as automated ore pre-concentration systems, composite fill preparation and delivery systems, as well as continuous mechanized mining methods are explored. The impacts and benefits of applying these integrated technologies to the mining system are defined and quantified through research, testwork, engineering design and systems analysis. Custom geo-metallurgical evaluation tools incorporating mineralogical, metallurgical, geophysical and geotechnical methods have been developed to allow the assessment of ores in terms of their potential for the adoption of the proposed approach. A computerized parametric evaluation model has also been developed to quantify the potential impacts and benefits using data from this testwork. A wide range of case studies have been investigated with positive results, and important conclusions are drawn towards the potential for application of the concept as a generalized case.

Soil cover systems are an integral part of a mine reclamation program and are increasing in area. Knowledge of temperatures and thermal properties in the cover system provide important information regarding the energy balance, thermal regime, as well as preliminary insight into soil water content. Cover system temperatures and thermal properties are measured at a small number of vertically intensive profiles. Current methods do not provide any information as to the spatial variation of temperatures and thermal properties at scales other than the point scale. The objective of this study was to investigate the spatial scaling of thermal properties in reclamation cover systems. A distributed temperature sensing (DTS) system was installed in three cover systems of various textures and configurations. Semivariogram analysis demonstrated that on a 40 m slope consisting of mineral soil over sand (Site #1) soil temperatures did not exhibit any spatial structure, due to the presence of vegetation. A 100 m cover system comprised of a structureless sand (Site #2) was confirmed to be spatially uniform through semivariogram analysis. Semivariograms at Site #2 displayed secondary structure that corresponded to the 65 m plateau and 35 m slope. Site #3 consisted of a uniform peat and a 2% slope. Spatial structure was non-existent at Site #3 and was attributed to the unique thermal properties of peat that magnified the effect of microtopography on the surface energy balance. A method to estimate apparent thermal inertia (ATI) using DTS measurements at the soil surface was developed. Apparent thermal inertia was found to be less uncertain than the current standard apparent thermal diffusivity. The ATI method was determined to be the preferred method as it was related to soil water content and not prone to estimation errors due to imprecise depth measurement. The spatial scaling properties of a 236 m cover system (Site #3) were investigated using estimations of ATI. Measurements were taken every meter along the transect for bulk density, elevation, air-dried thermal conductivity and air-dried volumetric heat capacity. The dominant scale of variation in ATI was not related to physical or thermal properties, which tended towards the 3 m scale (bulk density and thermal conductivity) or the 108 m and field scale trend (elevation and volumetric heat capacity). The dominant scale of variation in ATI shifted between 30 m and the field scale trend and was related to water content as represented by the soil matric potential. A dry cover system tended to homogenize thermal property distribution, leading to a dominance of the 108 m and field scale trend. Wetter days led to a shift to the 30 m scale, with intermediate days showing a mix in scale dominance. Information on thermal property spatial scaling properties of cover systems can be used to optimally design monitoring systems that measure at the same scale as that which the cover is performing. Characterizing the spatial variability of the system will lead to better cover system designs and ultimately a more sustainable system.

Increased demand for rare earth elements (REEs) for applications in modern technologies has led to an increase in REE exploration. Several deposits are expected to begin mining within a decade, but few studies have examined the possible environmental effects created by these mines. Metal toxicity is thought to be greater in aqueous environments when metals occur as free ions rather than complexes, and the speciation can also impact the treatment technologies utilized to reduce metal concentrations. This research investigates the mineralogical source of REEs and the mechanism of REE mobility in low-temperature waters that have interacted with pilot plant tailings from the Nechalacho deposit, Northwest Territories. The Nechalacho deposit is owned by Avalon Rare Metals Inc. and located approximately 100 km east of Yellowknife. The deposit is hosted within a hydrothermally altered layered nepheline-sodalite syenite in the peralkaline Blatchford Lake complex. The main REE ore minerals are zircon, fergusonite, allanite, monazite, bastnäsite, and synchisite-parasite. Characterization of the tailings using mineral liberation analyzer (MLA) show that the ore minerals are fine grained and well liberated. Bastnäsite and synchisite-parasite are the only potentially soluble ore minerals at low temperature and near-neutral pH. Shake flask experiments were designed to simulate the interaction of tailings with three different leach waters to identify soluble phases and mobile elements. Decanted solutions from the shake flasks were filtered to 0.45µm and 0.01µm. Speciation modelling of the 0.01µm filtrate suggests that carbonate ligands will form the dominant complexes with the REEs, and <2% occur as free metal ions. Higher proportions of LREEs (1-6%) occur as free metal ions than HREEs (<1%) and LREEs occur in higher concentrations (2 to 8 times greater) than the HREE. REEs were found in the colloidal fraction ([REEcolloid] = [REE0.45µm] – [REE0.01µm]). Ionic strength is the dominant control on distribution of REEs between colloidal and dissolved fraction. Colloids captured on filters from ultrafiltration analyzed using scanning electron microscopy and synchrotron microanalysis show REEs are hosted in colloidal rare earth minerals (e.g. zircon) and also show colloidal humic acid, Fe-oxides and Mn-oxides. Speciation modeling shows that REE sorption to these phases is probable. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2014-05-28 11:06:41.351

An essential component for evaluating the performance of a mine site after its closure includes the tracking of water movement through mine waste such as tailings and overburden. A critical element of this evaluation is the measurement of the volume of water stored in the closure landform. The objective of this project was to design a time domain reflectometry (TDR) device that could be used to measure the volumetric water content of a soil profile to depths of 10 to 20 m. Upon completion of this project, the device will be integrated onto ConeTec’s cone penetration testing (CPT) shaft for initially monitoring Syncrude Canada Limited’s northeastern Alberta oil sands mine site. The objective of this project will be achieved through at least two phases of research and development; this thesis concentrates on the first phase. In this phase, research focused on prototype development through laboratory testing to determine appropriate TDR probe geometries and configurations that could be integrated onto a CPT shaft. Considerations also had to be made for protecting the integrity of the probe during field use and mitigating the effects of highly electrically conductive soils common in reclaimed mine sites. A number of different prototype designs were initially investigated in this research, leading to the development of a refined prototype for advanced testing. Testing for the project was carried out first in solutions of known dielectric constants and salinities, and then proceeded to soils with a range of known water contents and salinities. Good quality electrical connections were found to be crucial for generating waveforms that were easy to interpret; bad connections resulted in poor results in a number of cases. Decreased probe sensitivity was observed in response to increased rod embedment within the probe variants. A far greater decrease in sensitivity was seen in the results of the fully sheathed rods, although the sheathing was effective for extending the range of the probe in electrically conductive testing conditions. Despite poor results that were seen in some of the tests, overall the results were promising. In particular, results from the push-test showed that the probe was able to monitor changes in water content with depth.

The integration of automated ore pre-concentration and waste disposal functions into the hard rock metal mining system, prior to treatment by conventional grinding and flotation, is proposed as a novel interpretation of Mine-Mill Integration for improving the economics and environmental impact of exploiting deep, low-grade or otherwise marginal mineral deposits. The proposed approach seeks to reject coarse, barren waste from the ore stream as early as possible in the mining cycle, and safely dispose of it as backfill underground. The concept is proposed as a Lean Manufacturing approach to hard rock mining, as an alternative to improving the economics of mining simply by increasing the mining rate. Lean Manufacturing philosophy seeks to design out overburden, smooth production, and eliminate waste from the system. It is suggested that the introduction of these systems into the hard rock mining process addresses all three of these areas of Lean thinking, and is thus an important approach to be considered for surface or underground mines wishing to simultaneously improve efficiency, economics and environmental performance, thus increasing the life, and the sustainability of the operation. The application of integrated mining, processing and waste disposal systems, where appropriate, is proposed as a strategy for the development of efficient new mining operations, or alternately the expansion of production at existing mines. Technologies specific to the success of the approach such as automated ore pre-concentration systems, composite fill preparation and delivery systems, as well as continuous mechanized mining methods are explored. The impacts and benefits of applying these integrated technologies to the mining system are defined and quantified through research, testwork, engineering design and systems analysis. Custom geo-metallurgical evaluation tools incorporating mineralogical, metallurgical, geophysical and geotechnical methods have been developed to allow the assessment of ores in terms of their potential for the adoption of the proposed approach. A computerized parametric evaluation model has also been developed to quantify the potential impacts and benefits using data from this testwork. A wide range of case studies have been investigated with positive results, and important conclusions are drawn towards the potential for application of the concept as a generalized case.

Thesis (M.S. - Renewable Natural Resources)--University of Arizona, 1982. / Includes bibliographical references (leaves 72-77).