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By J. R. Batista, J. C. Young

Leachates from gold heap-leaching mines may contain selenium concentrations as high as 2 mg/L. Previous studies report satisfactory selenium adsorption by activated alumina from relatively "clean" drinking waters. However, the findings of these studies cannot be directly applied to the treatment of mine leachate where other ions compete for the alumina adsorption sites. This study evaluated the adsorption of selenium from a mine leachate to develop design parameters for a full-scale activated alumina process. The study revealed that 68% of the selenium in the leachate could be removed by alumina at pH levels greater than 5.0. At pH levels less than 4, silica was poorly adsorbed by alumina, and selenium adsorption was improved. Silica adversely affected the selenium adsorption capacity.

Jan 1, 1998

By J. van Wijk

"Vertical material transport is one of the major challenges for the successful implementation of deep sea mining projects. The EU research project „Blue Mining” is focusing on sustainable solutions for deep sea mining operations, with one major goal being the advancement of Vertical Transport Systems (VTS). To investigate flow effects under realistic conditions, especially clogging effects, a 136 m high test facility for flow analysis in vertical transport has been constructed using available mining infrastructure. Tests are run in a closed circuit, using a system of downfall and riser pipelines connected to a compact sediment injection- and separation unit as well as the centrifugal pump. The riser is equipped with pressure sensors, as well as temperature sensors, flow meter, concentration meter and high speed camera to allow comprehensive analyses of the flow regime and behavior of transported material within the flow. Additional mobile measurement devices allow wear and tear analyses of pipe material. This paper focuses on the determining factors of the tests leading to the design as well as the installation and trial of the test facility itself and explains the used components and work principles. INTRODUCTION Since the 1970s several research projects had been conducted investigating in the possibility of deep sea mining. In recent times projects for deep sea mining operations have started again, considering the rising demand on natural resources, especially raw earth elements. Yet projects like the Nautilus project on the deposit Solwara 1 [1], or Japanese projects focusing on the region of Okinawa [2] and Chinese projects [3] planning on depths of “only” about 2,500 up to 3,000 m. Until now no economical deep sea mining project was realized, due to the enormous difficulties of deep sea environments. Vertical material transport is one of the major challenges for the successful implementation of deep sea mining projects, considering transportation heights up to 5 km. The EU research project „Blue Mining” is focusing on sustainable solutions for deep sea mining operations, with one major goal being the advancement of Vertical Transport Systems or VTS [4]. Critical parts of the system would be identified and investigated to deliver solutions and higher the technology readiness level to a level were planning of a pilot project can be considered. At first case examples for mining projects of seafloor massive sulfides (SMS, 1,600 m water depth) and manganese nodules (MnN, 5,000 m water depth) had been calculated on basis of economical frame conditions, such as planned production rates to be efficient. As depicted in Figure 1 two major possible systems had been used for comparison, airlift system and pump system, considering multiple pump stations or single pumps. Based on the results and comparisons for the calculated vertical transport systems critical components and flow effects had been identified."

Jan 1, 2018

By A. Roper

Since the Toronto conference in May 2002, the International Council on Mining and Minerals (ICMM) has made progress on the road to sustainability. Fifteen of the world?s largest mining and metal producing companies and twenty-five associations have made a long term commitment to ICMM to improve the environmental and social sustainability of their activities. Sir Robert Wilson (Rio Tinto) assumed the chairmanship of ICMM in October 2002. By December 2002, the Council had approved a Strategic Vision and an operating plan for 2003. Both have been posted on the ICMM website (www.icmm.com). ICMM?s Operating Plan sets out three priority tasks: - Providing strategic leadership to achieve improved sustainable development performance in the mining, minerals and metals industry. - Contributing to international policy discussions on cross-cutting issues of importance to the industry, in collaboration with national and commodity associations. - Promoting dialogue and partnership with other organizations to catalyze sector?wide sustainability initiatives.

Jan 1, 2003

By G. F. Weaton

1.1 The purpose of this paper is to show the way by which estimates are made of the tonnage and grade of iron ore and taconite reserves of Minnesota. 1.2 The procedures include those of estimating the open pit reserves of: (a) Natural iron ore, and (b) Taconite 1.3 The methods of estimation which will be discussed are primarily based on the information from exploring iron ore deposits. They consider the geology of the deposit as well as the contained mineral of potential value. 2.0 Some geologic, engineering, and economic principles. 2.1 Ore 2.11 "In the broad economic sense, and from a legal standpoint as well, ore is mineralized rock, which under appropriate conditions of time, space, technology, economics, and politics, can be mined, processed, and made to yield a saleable metal , or other mineral products at a profit."(Parks, 1957) Stated differently, metallic ore is rock material from which presently known methods of beneficiation, a merchantable concentrate, suitable for use in the manufacture of metals at a profit, can be produced. Crude ores as low as 0.38% metal, as in the case of copper and even lower in the case of the precious metals.

Jan 1, 1985

By Andrew C. Katen

The mining industry faces increasing geopolitical risk in the coming decades. Constraints such as resource nationalism, corruption and social license could grow to outweigh fundamental limitations like geology or supply and demand (Ernst & Young, 2013; Verrastro et al. 2010). Lurking beneath these more immediate and palpable concerns, however, may be more significant risks entrenched in geography and history. Deep-rooted cultural and strategic forces that emerge slowly ? or erupt suddenly and unexpectedly ? can generate momentous and far-reaching political, social and economic changes. While multinational enterprises routinely assess for political risk, the nature of minerals extraction means long-term and systemic geopolitical conditions are especially important for mining companies to identify and understand. Mine development is a decades-long process that binds companies to the land and makes changing course to avert emerging threats a difficult and costly option. Consequently, geopolitical assessment is a pertinent and valuable tool that mining companies can use to more comprehensively evaluate strategic threats and opportunities. Geopolitics is the study of society, politics and strategy through the lens of geography (Gray, 1996). Its emphasis on relatively permanent physical features of the earth makes geopolitics a uniquely valuable tool for assessing political risk. Topography, climate and natural resources have shaped, constrained and motivated peoples and governments throughout history. These influences transcend regimes, policies and borders ? and even states themselves ? which, by contrast, change often and dramatically. Framing politics against mountains, deserts and rivers supports identification of historical patterns and forecasts of emerging trends. In other words, the physical map provides an objective and consistent model for studying a subjective and dynamic subject such as politics (Sloan and Gray, 1999). Consequently, geopolitical assessment can highlight threats and opportunities that go unaddressed by other risk methodologies that emphasize current conditions (Glancy, 2012). Taken together, the permanence of geography, hindsight afforded by centuries of political history, and interconnectedness of world events makes geopolitical assessment a valuable approach for conceptualizing strategic risk.

Mar 1, 2014

By S. N. Chadha

INTRODUCTION The work described here refers to the Genesee River Interceptor Southeast Project. This project is a part of the Combined Sewer Overflow Abatement Program, Phase I, for the Rochester Pure Water District, Rochester, New York. Our contract required the design of a 13,200-feet long main tunnel, 14 feet finished diameter, approximately 100-120 Feet below ground; drop shafts and diversion tunnels to deliver surface flow to the main tunnel; a gate chamber whereby the main tunnel is dropped 35 feet, and provision made for connection to the future tunnel in Phase II, as well as a host of other surface structures. Cross sectional dimensions for the structures involved varied from 16 feet circular to a 20'x50' horseshoe, in a competent rock formation consisting of Lockport Dolomite and Rochester Shale. In the construction of a rock tunnel, the problems of the tunnel designers are as follows: 1. To evaluate stresses in the rock as a result of excavation. 2. Design a temporary support system to prevent any rock failure during the period of construction. Design of this temporary support system is empirical. Design loads given by empirical relations are dependent upon the rock quality and size of opening. Temporary support system may either be steel frames closely spaced along the length of tunnel and tied together, in the case of poor rock, or, an even spacing of rock bolts in the case of competent rock. 3. Design a final lining for the service loads. Service loads, in our case of a water-carrying tunnel, are hydrostatic pressure due to ground water, deadweight of lining) pressure of contained water and time dependent rock loading. The constitutive properties of the rock are extremely complex because of discontinuities, pre-existing stresses due to overburden, material symmetries and changes of initial state associated with the process of excavation. The changes of initial state may be changes of stress fields along with the consequent yield of the material or the extension of existing discontinuities.

Jan 1, 1977

By A. E. Isaacson, D. B. Dreisinger, G. A. Kordosky

The U.S. Bureau of Mines is researching the application of solvent extraction technology to highly acidic (pH < 1) copper leach liquors. As increasingly complex copper ores are mined for leaching, use of highly acidic leach solutions maybe necessary to effectively recover the contained metal values. A mixture of two commercially available extractants, based on aldoximes and substituted 8-hydroxyquinoline, which has a high transfer efficiency has been identified. A synthetic leach liquor, containing 5 g/L Cu at pH 0.9 was processed utilizing the mixed extractant and a laboratory SX circuit. The loaded organic was stripped with a synthetic barren electrolyte compatible with electrowinning technology.

Jan 1, 1993

By D. Hong, K. N. Han

The leaching behavior of rhenium in ammonium iodide solutions with iodine as oxidant was studied. Experiments were carried out in an autoclave to investigate the effects of stirring speed, temperature, solution pH, and iodine and iodide concentrations on the dissolution of rhenium. It was found that a high temperature and a high solution pH were essential for the efficient leaching of rhenium. The dissolution rate was found to be dependent upon the concentration of iodine and iodide. It was concluded that the dissolution of rhenium under the conditions studied was controlled by the mass transfer of iodine with an apparent activation energy of 15.8 kJ/mole.

Jan 1, 1999

By Basil W. Mercer

Increased emphasis on industrial pollution control has intensified investigation of waste treatment technology for methods of reducing the amount of pollutants discharged by industry. The mining and mineral processing industry can point to a record of considerable accomplishment in the field of wastewater treatment and reclamation because these operations are so frequently an integral part of the entire operation of an ore dressing facility. This is amply demonstrated by metal producers in the arid regions of the Southwest where water shortages require maximum use of available water. For example, the copper industry in Arizona during 1960 employed an estimated 184 billion gallons of water of which 87% was reused water. (1) Only 0.0003% was discharged to streams and the remainder was consumed by evaporation (8%) and seepage (5%). The most severe pollution problem facing the mining and ore processing industry today is that resulting from acid mine drainage. This problem is largely associated with the mining of coal although it occurs to a lesser degree with the mining of other materials. The degradation of streams by acid mine drainage in the vicinity&apos; of the Appalachian coal fields has been widely publicized and a major effort is underway to determine the best means of correcting this situation. Other forms of pollution from mining operations are less well-known, but it is anticipated that improved or advanced waste treatment techniques will be required for segments of the industry to comply with new pollution control regulations. The current emphasis on redefining hazardous levels for heavy metals and various chemicals with regard to the total environment will in all likelihood lead to tighter discharge controls in some cases. It is the purpose of this paper to review some of the waste

Jan 1, 1971

By D. W. McGlashan

Zeta potential changes were determined as a function of pH, metal ion, and surfactant concentrations. Prom the analysis of data, flotation experiments were carried out to correlate float-ability with the differences in zeta potential. Cassiterite in water bears a negative zeta potential, The zeta potential of cassiterite is sensitive to pH changes; the electric double layer arises from the preferential adsorption of H+ and OH- ions and subsequent ionization of the hydroxylated surface. It is suspected that hydronium-ion concentration may cause reversal in the sign of the zeta potential. The ZPC was found to occur at pH 3.4. Metallic ions and the hydrated ions thereof affect the zeta potential of cassiterite in differing degrees of intensity. Without prior activation, sulfonated surfactants do not change the zeta potential of cassiterite. Sodium alkyl aryl sulfonate is especially active on lead-activated cassiterite and ferric-activated cassiteriten Microcalorimetric fiests confimed the activity of ions on cassiterite and showed the hydrated character of cassiterite smfaces. Close correlation between zeta potential and microflotation results was achieved.

Jan 1, 1969

By M. D. Loy

In addition to products available from private vendors, many useful programs are developed at universities - in fact, many of these programs led the way to commercial development. Other projects are assigned to consultants with backgrounds in system design and mining. Both types of development have led to programs that can be acquired for the cost of a tape or disk. This paper highlights several underground mining packages. These programs consist of: ? USBM model-developed by the United States Bureau of nines. ? PSU model-developed by Pennsylvania State University. ? VPI model-developed by Virginia Polytechnical Institute and State University. ? NUS model-developed by NUS Corp.

Jan 1, 1987

By Gregory M. Rumbaugh, Todd R. Kostecki, Christopher Mark

The paper examines five massive pillar collapses in underground stone mines in the eastern United States from 2015 to 2021. These collapses caused significant airblasts, surface subsidence, and damage to mine infrastructure. The study identifies factors contributing to pillar collapses, such as slender pillars with width-to-height ratios of 0.8 or less, and proposes a framework for evaluating and mitigating collapse risks.

Nov 1, 2023

Longwall mining is a commonly used method of coal extraction that involves the complete removal of large, rectangular panels of coal. Longwall mining causes the immediate seam roof to break and fall into the void created by mining. The convergence of the surrounding strata towards the mining void causes subsidence on the surface. The subsidence magnitude is related not only to the mining depth, the topography, the geological features and the overburden materials, but also to the sequence of the strata overlying a coal seam. In additional to the vertical subsidence which is evident at the surface, there are also horizontal movements inwards toward the centre of the void, which cause the surface to tilt, bend, stretch and com-press. This paper presents a parametric investigation of the influence of the overburden stratigraphy to surface deformations due to longwall mining using 2D finite element models. Models simulate rock movement by applying equivalent edge load to the open roof.

Jan 1, 2008

By CADEN VITTI, Barbara J. Arnold

Mine tailings, the byproduct of mining and mineral processing, are increasingly mass-produced as a result of increased demand for metals and minerals as well as the advancement in technology that allows for the exploitation of lower-grade ores. Lower grades can increase the volume of tailings that may contain new gangue minerals that should be evaluated for the presence of critical minerals and other valuable metals. The practice of reprocessing, while relatively new, is crucial to reducing environmental damages, obtaining valuable critical minerals from waste, and contributing to more sustainable repurposing and disposal methods. With the increase in tailings dam failures in recent years, there is a large motivating factor in remining and removing the potential hazard to benefit the safety of potentially impacted communities. In analyzing the perspectives of various domestic and international studies, this literature review will determine the feasibility of reprocessing and reutilizing mine tailings waste for a more sustainable future while exploring current practices that have benefitted ecosystems and communities.

By J. A. Lombardi

"EXECUTIVE SUMMARY The use of membranes for the treatment of Acid-Mine-Drainage (AMD) water has been a 35 year mining industry quest that has only recently produced commercial scale Zero-Liquid-Discharge (ZLD) plants. The process of development of the membrane treatment of AMD has been defined by the water treatment industry’s efforts to control gypsum scaling of the membranes, an artifact of the concentration of calcium and sulfate ions on the concentrate or “brine” side of the membranes. Improved anti-scalants, changes to membrane surface geometry and a lowered permeate flux rate were all part of solving the calcium sulfate (gypsum) scale formation problem. Whether used singly or as part of a multi-stage membrane treatment process, the production of “left over” membrane concentrate or brine, in any volume large or small, was a second barrier to adoption of the method by the mining industry. The two identified “final brine” treatments were a) solar evaporation ponds and b) mechanical evaporators. Brine disposal by solar means is typically site limited to flat terrains or high net evaporation locations. Mechanical evaporation-crystallization is applicable at all sites but, typically, at onerously high ownership and operating costs. Miwatek, a South African water treatment start-up, has entered the mining AMD ZLD marketplace with two new, pilot-scale tested, processes, both of which are predicated on the innovative treatment of a reasonably concentrated AMD and neither of which produces a final brine that requires disposal. In the Miwatek Brine Treatment, MBT, method the membrane brine is caustic pH adjusted and de-calcified precedent to passage through a second membrane plant. The caustic is generated on-site by a lime treatment of the second-membrane concentrate. The first- and second-stage permeates are blended for discharge. The process usually yields no “final brine” for disposal. In the Miwatek Ettringite Treatment, MET, method a low pH first-stage membrane brine is lime treated in two or three steps in the presence of aluminum in a way that metal hydroxide and calcium sulfate solids are formed and purged from the system. Sufficient aluminum is often present in the feed water to, with judicious recycling, enable operation of the lime-aluminum treatment without the purchase of outside aluminum reagent. The first-stage membrane permeate is blended with the lime-aluminum treated membrane concentrate for discharge. The indications are that the method can comfortably meet the low 250 -500 ppm SO4 discharge water quality standards that have most recently been proposed in South America. The process yields no “final brine” that requires disposal. Projected own-operate costs for the MBT and MET systems are less than the estimated costs for all identified alternative treatments."

Jan 1, 2015

By Gregg A. Swayre, Roger N. Clark, Stephen J. Sutley, Kathleen S. Smith

Imaging spectroscopy is a relatively new remote sensing tool that provides a rapid method to screen entire mining districts for potential sources of surface acid drainage. An imaging spectrometer known as the Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) measures light reflected from the surface in 224 spectral channels from 0.4 - 2.5 µm. Spectral data from this instrument were used to evaluate mine waste at the California Gulch Superfluid Site near Leadville, Colorado. Here, the process of pyrite oxidation at the surface produces acidic water that is gradually neutralized as it drains away from mine waste, depositing a central jarosite zone surrounded by a jarosite + goethite zone, in turn surrounded by a goethite zone with a discontinuous hematite rim zone. Leaching tests show that pH is most acidic in the jarosite and jarosite + goethite zones and is near-neutral in the goethite zone. Measurements indicate that metals leach from minerals and amorphous materials in the jarosite + goethite and jarosite zones at concentrations 10 - 50 times higher than from goethite zone minerals. Goethite zones that fully encircle mine waste may indicate some attenuation of leachate metals and thus reduced metal loading to streams. The potential for impact by acidic drainage is highest where streams intersect the jarosite and jarosite + goethite zones. In these areas, metal-rich acidic dace runoff may flow directly into streams. The U.S. Environmental Protection Agency estimates (U.S. EPA, 1998) that mineral maps made from AVIRIS data at Leadville have accelerated remediation efforts by two years and saved over $2 million in cleanup costs.

Jan 1, 2000

By Stuart Ratcliffe, Denis Kidby

The development of Vitrokele™ Technology over the last 10 years is reviewed with reference to mine site piloting and com­mercial applications. The first mine site piloting was conducted in Australia in 1989 followed by a further six continuous site trials in Australia, Canada and the USA. These major pilot plant studies are complemented by over 50 laboratory scale batch and pilot testwork programmes. The first commercial plant using Vitrokele™ Technology was the Connemara project commissioned in Zimbabwe in 1995. Subsequent to this, three commercial scale projects have been designed using Vitrokele™ to recover precious metals, base met­als and cyanide. The various projects are discussed with relation to the differ­ing flowsheets applied to each particular case.

Jan 1, 1998

By J. Noll, A. Miller, J. Volkwein, C. Pritchard

Hecla Limited, Magee Scientific, and NIOSH have combined efforts to evaluate an in-situ air filtration system for use in an underground mine environment. The purpose of the collaboration was to determine the efficacy of such a technology for reducing the concentration of airborne diesel particulate matter (DPM), with the aim of improving air quality in underground hardrock mines. A secondary goal was to evaluate the use of an Aethalometer as a means of real-time measurement of black carbon as a surrogate for DPM. The evaluation included measuring the DPM-capture efficiency of the filter when it was pre-loaded with dust. Toward this end, rock dust was introduced at the filter inlet to create a dust layer on the filter surface, with the intent of providing improved capture of the much smaller DPM particles. The filtration efficiency for DPM was assessed by comparing measurements of DPM taken at the inlet and outlet of the system, using both real-time and time-weighted-average approaches. The real-time measurements were performed with the model AE33 Aethalometer® made by Magee Scientific. The results of the NIOSH 5040 method analysis were used to assess the effects of the system on time-weighted-average concentrations of total carbon. Results showed a reduction in DPM concentrations in the range of 82%-89%. While the calculated efficiencies based on the two different measurement methods were similar, the DPM levels reported by the Aethalometer were higher, possibly due to differences in the performance of the size-selectors used for the two methods (impactors versus cyclones). More research is required to develop a robust correlation between the two methods, to support the use of the Aethalometer for future mining applications. The advantage of the Aethalometer is that it can measure and record DPM levels for weeks at a time, and can be directly connected to a mine monitoring system, potentially at multiple locations. Ideally such data can be used to initiate the startup of the filtration system should DPM concentrations reach an action level. This work demonstrated that in-situ filtration systems, modified to collect DPM and coupled with real-time monitoring, show promise at reducing DPM concentrations in the mine environment.

Jan 1, 2016

By D. M. Davidson

The economics of geologic exploration have changed materially in the past decade primarily due to the change in three basic factors, namely, increased wages and salaries, increased cost of materials, and a greater complexity in methods of exploration. Following the general economic pattern over the past ten years, exploration costs, have, in general, increased, although there is one heartening exception. A comparative picture is complicated because of advances in techniques which ensue from the introduction of new methods and devices largely for aerial exploratory work, Some of these methods were either in their infancy or unknown before World War II. Geological exploration may well be considered as a form of applied research. True, it has peculiarities from this standpoint some advantageous, others disadvantageous, Some of the advantages lie in the fact that exploration success does not involve the production of a new product which necessitates advertising expense and marketing problems. In normal times there is a well established market for the fruits of a successful mineral find. The outstanding disadvantage of exploration lies in the enigma of deciding when to quit if the sought fop prize is elusive. In the search for buried treasure, man?s curiosity is apt to color his judgment. Even the so-called detached scientist may fall &apos;all too readily into the wishful thinking of the old- time prospector who is lured on by the thought that the next pull from the drill hole, or the next round from the face will reveal a bonanza. It involves mature judgment and experience to ascertain the stage in exploration when further work is not justified.

Jan 1, 1958

By Madan M. Singh

Increasingly, geotechnical data are being collected for various types of coal development projects. In many cases, a specific design concern is addressed. However, many data collection programs are not intended to immediately support mine design activities or to resolve a specific concern. The following discussion describes some current geotechnical approaches in mine planning, development of reserves, and peripheral activities. Types of Data Collection Programs Geotechnical data collection is increasingly becoming a part of standard coal exploration programs, performed along with stratigraphic evaluations and coal quality tests. The aims of such programs vary. The purpose of the exploration may be to fill out the portfolio on a block of reserves that is to be sold, leased, or held for potential future development. In such a case, a generic suite of geotechnical data are collected. The resulting engineering reports may touch on the more well known mining problems of the area, but detail may be lacking. The geotechnical data are mostly intended to enhance the saleability of the package. Mine design alternatives are generally not addressed.

Jan 1, 1985