In 2010, as part of the remediation of the abandoned Faro Mine Complex (located at 62 o N latitude in northern Canada), Yukon Government constructed a 28 hectare, low-infiltration dry cover and associated water management system over the Grum Sulphide Cell, which is a highly-sulphidic part of the Grum Waste Rock Dump. In May 2011, above normal snowpack and record-high temperatures created excessive meltwater runoff that eroded some of the till cover. This resulted in a short-term discharge of non-compliant water (high in suspended sediment and zinc) to the environment. The root causes of the non-compliant discharge were related to above-average snowmelt events, bench ditches that became plugged with snow and ice, lack of vegetation establishment on the soil cover, improper toe berm grading and insufficient hydraulic capacity at the outflow from the cover. In June 2011, the site owner, Yukon Government, retained an engineering consultant, to design and supervise upgrades to the cover grading and water management, including the provision of contingency water storage in the down-gradient waste rock dump. Two phases of construction activities were undertaken between June and September 2011 consisting of the following aspects: cover revegetation, repair of erosion scars and toe berm regrading, grading to increase flow capacity of bench ditches, replacement of armour rock in collection channels, construction of a lined collection pond, installation of a pumping system and provision of unlined contingency storage in case of overflows. Snowmelt in May and June 2012 resulted in water management as intended by the upgrades and compliant discharge from the cover was achieved. Water quantity and quality results are provided for the 2012 runoff event, along with comments on the performance of the system upgrades and related monitoring program. Covers need to be monitored and performance assured before water discharge directly to the environment can be assumed.

Indium and other geologically scarce metals are routinely integrated into green technologies and modern consumer electronics. The manufacture of solar cells and liquid crystal displays (LCDs) relies strongly on continued indium supply, yet very little research has been conducted to determine what total resources exist to meet future or even present needs. This paper provides an improved understanding of the nature of indium resources and the current and future production and supply of this critical metal through a summary of global trends in indium production and demand, and through a preliminary account of global code-based reporting of indium mineral resources. Authors also present an overview of the potential for indium extraction from mine wastes and recycled electronics using Canadian and Australian case studies. Our preliminary data suggest that considerable resources are likely to exist in a diversity of deposits globally, which have the potential to meet long-term demand for indium. However, it is clear that a secured future supply of this metal will require some shift of focus from conventional extraction practices. It will be necessary to revisit controls on the conversion of resources to reserves and to supply and the discovery of additional resources to replace those depleted by continuing production. The prospects for indium supply from mine wastes and recycled electronics are found to be substantial, and these sources warrant greater consideration given their probable environmental and social advantages over the discovery and development of new primary indium deposits.

Se analizan los aspectos geológicos y los métodos de beneficio usados históricamente en el Distrito Minero de Guanajuato para plantear hipótesis respecto a las condiciones geoquímicas que pueden encontrarse en los residuos de la extracción. Se compiló información sobre las condiciones geográficas del distrito, los tipos de mena, la historia de producción, los procesos de beneficio y las toneladas de oro y plata recuperadas. Con estos datos se estiman las cantidades de residuos que puede haber dispersos y se proponen las cantidades de calcita y pirita presentes en los jales en función de la ubicación del yacimiento de procedencia.

The present study focuses on the mineralogical
and geochemical patterns of mining and ore-processing
wastes from some occurrences in the Eastern Carpathians;
its aim is to identify the main factors and processes that
could lead to the pollution of the environment. In this
respect, the following types of solid waste were investigated:
efflorescent salts developed on the surface of rock
blocks from a quarry, ore-processing waste from two tailings
ponds, and salt crusts developed at the surface of a
tailings pond. The potential risks emphasized by these preliminary
investigations are the following: (1) the risk of
wind-driven removal and transport of the waste from the
surface of tailings ponds, given that fine grains prevail (up
to 80 %); (2) the risk of tailings removal through mechanical
transport by water, during heavy rainfall; (3) the appearance
of hydrated sulfates on the rock fragments from the mining
waste, sulfates which are highly susceptible to the generation
of acid mine drainage (pH<4); (4) the high amount of
toxic elements (Pb, Cd, Cu, Zn, As, etc.) that acid mine
drainage leachates contain; and (5) the development of a salt
crust on the flat, horizontal surfaces of the waste deposit,
due to this very shape. Statistical data regarding the amount
of both major and minor elements in the tailings have revealed two statistical populations for nearly all the toxic
metals. This suggests that, beyond the effect that the tailings
have upon the environment through their mere presence in a
given area, there are alleged additional factors and processes
which intensify the pollution: the location of the waste
deposit relative to the topography of the area; the shape of
the waste deposit; the development of low areas on the
surface of the deposit, areas which favor the appearance of
salt crusts; and the mineralogy of efflorescent aggregates.

The Diavik Waste Rock Project, located in a region of continuous permafrost in northern Canada, includes complementary field and laboratory experiments with the purpose of investigating scale-up techniques for the assessment of the geochemical evolution of mine waste rock at a large scale. As part of the Diavik project, medium-scale field experiments (∼1.5 m high active zone lysimeters) were conducted to assess the long term geochemical evolution and drainage of a low-sulfide waste rock under a relatively simple (i.e. constrained by the container) flow regime while exposed to atmospheric conditions. A conceptual model, including the most significant processes controlling the sulfide-mineral oxidation and weathering of the associated host minerals as observed in a laboratory humidity cell experiment, was developed as part of a previous modelling study. The current study investigated the efficacy of scaling the calibrated humidity cell model to simulate the geochemical evolution of the active zone lysimeter experiments. The humidity cell model was used to simulate the geo-chemical evolution of low-sulfide waste rock with S content of 0.053 wt.% and 0.035 wt.% (primarily pyrrhotite) in the active zone lysimeter experiments using the reactive transport code MIN3P. Water flow through the lysimeters was simulated using temporally variable infiltration estimated from precipitation measurements made within 200 m of the lysimeters. Flow parameters and physical properties determined during previous studies at Diavik were incorporated into the simulations to reproduce the flow regime. The geochemical evolution of the waste-rock system was simulated by adjustment of the sulfide-mineral content to reflect the values measured at the lysimeters. The temperature dependence of the geochemical system was considered using temperature measurements taken daily, adjacent to the lysimeters, to correct weathering rates according to the Arrhenius equation. The lysimeter simulations indicated that a model developed from simulations of laboratory humidity cell experiments, incorporating detailed representations of temporally variable temperature and water infiltration, can be scaled to provide a reasonable assessment of geochemical evolution of the medium-scale field experiments.

Degradation of tetracycline (TTC) with a heterogeneous Fenton-like pyrite/H 2 O 2 process by pyrite from mine waste as a mineral catalyst was investigated. The study focused on identifying the main oxidizing agents and degradation mechanisms along with operational variables including solution pH, pyrite and H 2 O 2 concentration, contact time, solution temperature, and initial TTC concentration. Catalyst characterization tests revealed that pyrite is a mesoporous powder with a high degree of FeS 2 purity. Radical scavenger tests demonstrated that OH was the main oxidizing agent generated by both solution and surface phase reactions. During the pyrite/H 2 O 2 process, more than 85% of TTC was mineralized in 60 min and the maximum TTC removal was attained in the solution at an acidic pH value (4.1). The most abundant transformation products of TTC, formed by the attack of OH radicals, were simple chain carboxylic acids. Cultured cells of human embryonic kidney (HEK) were used for the cytotoxicity assessment of raw and pyrite/H 2 O 2 treated TTC solutions. The results illustrated that the viability of HEK cells was enhanced considerably after treating TTC solutions under optimal conditions. Accordingly, pyrite originating from mine waste is a practically effective and cost-effective catalyst in heterogeneous Fenton-like systems for mineralization and degradation of emerging contaminants such as antibiotics.

ABSTRACT
This paper reports preliminary results of a PhD research project related to the development of an alkaliactivated
geopolymeric binder using mineral waste mud from the Portuguese tungsten mine Panasqueira
which is still operating. Mineralogical analysis indicates that the waste mud is compose mainly of muscovite
and quartz with a high content of iron and alkali metals. Results of the dehydroxylation process are presented
by x-ray diffraction and infrared emission spectroscopy patterns of quenched waste powder and also from
compressive strength of alkali-activated mortar specimens, showing a significant potential as a geopolymeric
source precursor.
Considerations about Portuguese industrial waste production are made showing a high level ratio of CO2
emissions mostly from cement industry, a nation-wide lack of fly ash and blast furnace slag to be used as
cementitious by-products and huge amounts of quarrying and mining wastes and also the need to preserve it`s
large and protected natural areas leading to the use of alumino-silicate minerals as the only reasonable
alternative to the development of alkali-activated friendly environmental binders.
Materials raw cost comparisons between Portland cement based concretes and alkali-activated geopolymeric
based concretes are also made showing that Portland cement based ones are by far the most economic ones
but not for very long due to the expected increase in Portland cement cost under the recent implementation
of CO2 emissions trading scheme (ETS).

Incorporation of barite-fluorspar mine waste (BFMW) as a fine aggregate additive has been investigated for its effect on the mechanical and shielding properties of cement mortar. Several mortar mixtures were prepared with different proportions of BFMW ranging from 0% to 30% as fine aggregate replacement. Cement mortar mixtures were evaluated for density, compressive and tensile strengths, and gamma ray radiation shielding. The results revealed that the mortar mixes containing 25% BFMW reaches the highest compressive strength values, which exceeded 50 MPa. Evaluation of gamma-ray attenuation was both measured by experimental tests and computationally calculated using MicroShield software package, and results have shown that using BFMW aggregates increases attenuation coefficient by about 20%. These findings have demonstrated that the mine waste can be suitably used as partial replacement aggregate to improve radiation shielding as well as to reduce the mortar and concrete costs.

Pyrite mine waste was used as a non-toxic and natural catalyst for the activation of peroxydisulfate (PDS) and peroxymonosulfate (PMS) to oxidize tetracycline (TTC), one of the most extensively used antibiotics worldwide, in contaminated water. The results demonstrated that PMS was activated more effectively than PDS by using pyrite. Scavenging experiments indicated that both OH • and SO 4 • − were the main oxidative species in the pyrite/ PMS process, while SO 4 • − was more dominant. A high degradation of 98.3 % and significant mineralization (up to 46 %) of TTC (50 mg/L) were achieved using pyrite activated PMS at a reaction time of 30 and 60 min, respectively. In-vivo toxicity of raw and pyrite/PMS treated TTC solutions was evaluated using biochemical and histopathological assays. The results revealed that the pyrite/PMS process significantly decreased the nephro-toxicity (90 %) and hepatotoxicity (85 %) effect of TTC. Catalyst reusability was evaluated under cycling conditions. No significant decrease in process efficiency was measured between the first and fourth cycle (<3% decrease in TTC removal). In conclusion, mine waste pyrite nanoparticles can be considered as a non-toxic and clean catalyst to activate PMS for an effective detoxification, degradation, and intermediate mineralization of TTC, as a refractory water pollutant.

Incorporation of barite-fluorspar mine waste (BFMW) as a fine aggregate additive has been investigated for its effect on the mechanical and shielding properties of cement mortar. Several mortar mixtures were prepared with different proportions of BFMW ranging from 0% to 30% as fine aggregate replacement. Cement mortar mixtures were evaluated for density, compressive and tensile strengths, and gamma ray radiation shielding. The results revealed that the mortar mixes containing 25% BFMW reaches the highest compressive strength values, which exceeded 50 MPa. Evaluation of gamma-ray attenuation was both measured by experimental tests and computationally calculated using MicroShield software package, and results have shown that using BFMW aggregates increases attenuation coefficient by about 20%. These findings have demonstrated that the mine waste can be suitably used as partial replacement aggregate to improve radiation shielding as well as to reduce the mortar and concrete costs.

This paper reports detailed O 2 measurements of pyrite bearing sediments in a column study and their interpretation based on a hydrogeochemical modelling approach. The research focuses on the quantitative effects of effective diffusion and microbiologic activity on pyrite weathering and acidification. A column experiment was set up and O 2 saturation and moisture contents were monitored over 100 days. The anoxic material used for the column experiment was taken from a sediment core of a mining waste dump in the southern periphery of the Lohsa storage system in the Lusatia region of Germany. The measured O 2 breakthrough curves were modelled using the simulator SAPY, a one-dimensional reactive transport code which considers the kinetics of chemical reactions and the delivery of O 2 into the sediment. The simulation yielded a strong dependence of pyrite oxidation on the moisture content which was quantified by an empirical equation. It was shown that the oxidation rate was catalysed by microbial activity exceeding the rate of diffusive O 2 delivery. In order to develop a management tool for predictive issues the results have already been applied to natural environments in another study using the adapted model.