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By B. Oraee

Accurate estimation of equipment costs is a key factor in feasibility study and evaluation of design alternatives of mining projects. In this paper, capital and operation costs of backhoe loaders are estimated using multiple linear regression (MLR), based on principle component analysis (PCA). These cost functions are consisted of five independent variables; bucket size, digging depth, dump height, weight and horse power. The MLR is conducted in two steps. At the first correlation between independent variables is omitted using PCA technique. Thereafter, MLR functions are established using selected significant PCs and total cost functions are constituted as functions of initial variables. At the end, accuracy of functions are evaluated using mean absolute error rate method.

Jan 1, 2011

By Nick Rose, Mathieu Veillette, Matthew King

"The Teck Highland Valley copper (THVC) mine is located approximately 55 km (34 miles) southwest of Kamloops and approximately 20 km (12 miles) west of Logan Lake, BC, Canada (Fig. 1). Mining at THVC is conducted at three openpit operations comprised of Valley, Lornex and Highmont with a total annual output on the order of 300 kt (330,000 st) copper concentrate and 5 kt (5,500 st) of molybdenum concentrate. The Phase 8 pushback in the Valley Pit (Fig. 2) was mined from 2011 to 2016. Successful slope steepening occurred in the later stage of the pushback with the implementation of presplit blasting in 2015 and 2016.This article summarizes the investigation and design approach including: structural analysis, kinematic assessments of bench breakback potential, development of discrete fracture networks (DFNs) to characterize discontinuity fabric, rockfall modelling, 2D anisotropic limit equilibrium and 2D distinct element modelling, assessment of potential kinematic failure modes affecting double benches with 3D distinct element modelling and improved blasting techniques using e-dets. THVC is currently undertaking a mine life expansion involving the pushback of the west wall of the Valley Pit above Phase 8 to extend the mine life to 2029. Engineering geologyThe east wall slope in the Valley Pit is comprised of a 350-m (1,148-ft) thick sequence of glacial valley sediments that occur along the Highland Valley (Fig. 2), exposing an overburden slope up to about 225-m (740-ft) high below the crest of the ultimate east wall. The glacial overburden units consist of pro-glacial outwash and glaciofluvial deposits, glacial outwash sands and gravels interbedded with till and alluvial fans consisting of cross-bedded sands and sandy-gravels. Lacustrine sediments occur within the mid to lower portion of the glacial sequence and contain intervals of low-shear-strength clays and silts. Two large (1.3 and 7 Mt or 1.4 and 7.7 million st) waste rock buttresses were required to maintain slope stability using slot-cut and fill mining methods, as described in Fortin et al. (2011).The Valley porphyry deposit occurs in the central portion of the late Upper Triassic Guichon Creek Batholith, which intrudes assemblages of the Permian Cache Creek and Upper Triassic Nicola groups. The Valley deposit occurs in an area of intense fracturing near the intersection of the northerly trending Lornex Fault and the northwest to westerly trending Highland Valley Fault."

Apr 1, 2019

By S. Shi, J. Y. Hwang, B. Li

Silver, copper, and zinc are commonly known elements with antibacterial and antifungal capabilities. Attempts have been made to dope silver on minerals, glass, and ceramics and the resulting materials have been investigated for their antibacterial and antifungal properties. Since silver is expensive and very reactive, silver doped materials have been found inappropriate in some applications. Copper-vermiculite is investigated as an alternative. Vermiculite has high cation exchange capacity on the magnesium ion in the crystal structure. Copper ion may have a high tendency to replace magnesium because of similar charge interference and ionic radius. Copper-vermiculite is prepared by reacting vermiculite and copper chloride solution. By impregnating copper ions into the nanometer openings between the layers of vermiculite, it is possible to render the composite with antibacterial functions if the copper ions could be released gradually from the composite. The antibacterial efficiency of Cu-vermiculite against Escherichia coli was studied using the Halo method. The results show that Cu-vermiculite is effective for preventing the reproduction of the bacteria. Heat treatment of Cu-vermiculite at up to 400°C does not show significant changes in antibacterial activities.

Jan 1, 2002

By J. F. Lupo

Heap and valley leach operations rely on solution collection piping placed within the heap to enhance both solution recovery and to assist overall solution management. The most common piping used in leaching operations is solid or perforated High Density Polyethylene (HDPE) pipe and Corrugated Polyethylene pipe (CPE). These pipes are widely used because of their low cost, ease of installation, durability, and flexibility. The typical recommended maximum design depth of burial for HDPE and CPE pipes is on the order of 30 meters (100 feet). However, ore heap heights at many facilities exceed 30 meters and some are now approaching 180 meters (600 feet) in height. At very high ore heap heights, the stability and performance of HDPE and CPE pipes becomes a critical issue for leaching facility design and operation. Failure of solution collection piping can lead to poor solution recovery, high hydraulic heads on the liner system, and in some cases, unstable ore slopes due to high solution pressures near slopes. This paper presents a review of methods that have traditionally been used to evaluate pipe stability under high normal loads. A common shortcoming of these methods is the inability to account for beneficial effects of ore arching around pipes and the time-dependent creep (stress relief) behavior of polyethylene (PE) materials. A new analytical approach is developed and presented which includes the effects of ore arching around pipes and creep of PE materials. The results of the new approach show that PE pipes will deform under high heap loads, but can remain stable and functional. Pipe stability is shown to be dependent on the type of pipe backfill and initial backfill compaction. The new approach represents a useful tool for designing applications for PE pipe under high normal loads.

Jan 1, 2001

By E. A. Adey, C. Baciu, P. Whitbread-Abrutat, M. Varul, T. Ejdemo, R. K. Shail, F. Wall

Responsible mining requires stakeholder engagement throughout all operational stages and after mine closure. By assessing the current and anticipated future socio-economic and environmental impacts, a company can maximise the positive impacts they can have on a community, whilst minimising any negative impacts. Despite the current emphasis on companies maintaining effective stakeholder relations to gain their ‘social license’ to operate, findings of the present study reveal a wide variation in community expectations, with different degrees of ‘acceptability’ evident across seven sites in Romania (Rosia Montana), Sweden (Kristineberg), the United Kingdom (Cornwall), Bosnia Herzegovina (Vihovici) and Russia (Karabash, Gay and Mednogorsk). These variations reflect the current status of mining within a community, as well as its socio-economic background and the nature of existing engagement with mining companies already operating in the region.

Jan 1, 2011

? The economic health and national security of the U.S. depends on the continued availability of, and access to, reliable and affordable energy and mineral resources. However, America is hindered by a costly, inefficient and often redundant regulatory structure that thwarts domestic investment, expansion and job creation. The annual cost of federal regulations in the U.S. increased to more than $1.75 trillion in 2008; averaging $8000 per employee.(The Impact of Regulatory Costs on Small Finns, SBA, 2010) ? The complexity, uncertainty and delays within the current permitting system places the U.S. at a competitive disadvantage with many other countries that have both abundant mineral resources and a more welcoming business and regulatory climate. As a result, American and international mining companies often move overseas or across borders to invest capital, create local employment, and produce the critical minerals America must then import at higher cost, while sacrificing employment and economic stimulus. ? According to Behre Dolbear, the U.S. is ranked lowest globally due to the lengthy permitting period required before mine development can commence. (Where not to Invest, 2010).

Jan 1, 2011

By M. Moagabo

CO2 emissions from carbonate laden reclaimed mine spoil has been shown to pose a hazard to residents in homes built on or adjacent to such land. The objective of this project was to develop a soil CO2 flux survey protocol for assessing reclaimed mine land. The research involved CO2 chamber accumulation flux surveys; stable carbon isotope ratio analysis; statistical hypothesis testing to examine correlation between CO2 flux and soil temperature and moisture as well as spatial dependence; and geostatistics to map CO2 and delineate high flux zones. Soil temperature was observed to have a positive correlation with fluxes while soil moisture was observed to be negatively correlated. Spatial dependence of CO2 fluxes on reclaimed mine land was observed on one of the two study sites. The research suggests that macro-porosity and gas permeability may be important factors that explain CO2 migration in mine spoil. A flux survey protocol has been developed, based on these results, for reclaimed mine lands. The work demonstrates the capability of geostatistical methods to delineate high flux fields. Further research will be required to determine suitable thresholds for such analysis.

Jan 1, 2012

By Gunter Swoboda, Harald Wagner

Until a few years ago tunnel construction was based exclusively on experience. In recent years, however, numerical models have increasingly become an integrated part of tunnel design [2]. These models permit good evaluation of the tunnel's support behavior even before it is designed. In particular, numerical methods are highly suited for the development of new construction methods. The prerequisite for this is the application of high-performance pre- and postprocessors, permitting the design engineer to come to a quick interpretation of the analysis results. In future, 3D analysis will take on increasing significance, for which reason this paper also deals with this type of models.

Jan 1, 1993

By Georgy Cherkashov, Svetlana Babaeva, Tamara Stepanova, Firstova. Anna

Seafloor massive sulfides (SMS) study in the Russian Exploration Area at the northern equatorial Mid Atlantic Ridge began after signing the contract with International Seabed Authority in 2012. In order to evaluate the SMS resources in the course of exploration the major and rare metals with economic value should be determined. The evaluation is based on geochemistry and mineralogy and particularly on the type of rare metals occurrence in the SMS. As a case study research of the Semyenov cluster of SMS deposits have been conducted.

Sep 1, 2014

By Jacob Carr, Chenming Zhou, Nicholas Damiano, James Noll, Jingcheng Li

Machine-related injuries are one of the major safety concerns in underground coal mines. Severe injuries and fatalities occur when a miner is struck, crushed, or pinned by mining equipment such as a continuous mining machine (CMM), shuttle car, or a scoop. Proximity detection systems (PDSs) have been applied in mining to reduce these types of injuries and fatalities. All of the PDSs that are currently approved by the Mine Safety and Health Administration (MSHA) for use in underground coal mines are magnetic-field based and could be affected by metallic objects such as trailing cables. Researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated the influence of trailing cables on the performance of PDSs. In particular, the magnetic field coupled from proximity system generators to a de-energized trailing cable was characterized. The results show that significant energy can be coupled from the proximity system generators to a trailing cable when there is a closed loop in the cable. The effect on PDS performance from the magnetic field radiated around an energized trailing cable was also quantified for different current amplitudes in the cable. It is shown that the magnetic field caused by the electric current in the trailing cable mainly consists of a 60-Hz signal and its harmonics which causes little interference to the PDS. The results presented in this paper can help PDS manufacturers to design better systems that are more immune to these effects.

By K. V. Raj, C. A. Berry, A. T. Weakley, A. L. Miller, P. R. Griffiths, D. A. Parks

Diesel particulate matter (DPM) has been classified as a carcinogen to humans by the International Agency for Research on Cancer. As a result of its potential carcinogenic nature, DPM exposure is regulated by the Mine Safety and Health Administration. Currently, diesel emissions in the workplace are monitored by collecting the aerosol onto filters, which are then sent to a laboratory for thermal-optical analysis using the NIOSH method 5040. This process can take days or even weeks, and workers can potentially be exposed to excessive levels of DPM before the problem is identified. Moreover, the delay involved in getting the loaded filter to the lab inevitably means the loss of some of the more volatile organic carbon. To remedy this delay, researchers from the National Institute for Occupational Safety and Health are seeking to develop a field-portable, real-time method for measuring elemental and organic carbons in DPM aerosols. In the current study, the use of mid-infrared spectrometry was investigated. It is believed that mid-infrared spectroscopy is more suitable for use in a real-time field-portable device than thermo-optical analysis methods. This article presents a method for measuring organic carbon (OC) and elemental carbon (EC) in DPM for a broad range of OC/EC ratios. The method has been successfully applied to laboratory-generated and mine samples.

By K. Bounou, K. Komnitsas

"Risk quantification may be used as a sustainable development index in the mining industry, since it encompasses both economic and social factors. In addition, it may assist in the development of a framework, which is also indirectly related to sustainable development, to prevent accidents and improve health and safety standards. However, risk quantification in the mineral sector involves diverse activities and is considered a very difficult task. Although statistical data report accident severity rates, incident rates and accident frequency rates, none of these allow for accurate risk calculations. In this paper, two risk calculation formulas, which may be used to quantify risk, as well as to identify hazardous activities in a workplace, are proposed. Numerical examples are given based on statistical data available through the MSHA database. Also a combination of a decision/fault/event tree that allows risk quantification is presented."

Jan 1, 2005

By S. C. Chelgani

The Thor lake deposit is a world class resource of rare earth (REE) metals and minerals in Canada. Development work to optimize a REE mineral recovery process flow sheet is underway, however, given the ore mineralogy; the developed reagent scheme is relatively complex. As part of a research project, micro flotation tests were conducted on a feed sample in order to examine factors affecting stream partitioning. SEM-EDX was performed to evaluate variability in grain composition between streams (concentrate and tails) and TOF-SIMS surface analysis was used to determine statistically significant differences in surface species particularly related to potential activation (or depression) of the examined mineral phases. SEM-EDX analysis reveal that the concentrate has a significantly higher proportion of REE bearing grains (carbonates and phosphates) relative to the tail (almost none were identified). Spectral fingerprinting by TOF-SIMS has allowed for the identification of all reagent species investigated. Reagent signal intensity discrimination on test stream mineral surfaces was observed by the TOF-SIMS analysis using reagents at plant concentration levels. TOF-SIMS analysis confirmed that REE bearing grains reporting to the concentrate are doing so in response to collector attachment whereas grains reporting to the tail are doing so in response to a lack of collector and/or in combination with the presence of the depressant. The surface analysis of gangue phases reveal a similar reagent discrimination; the signal intensity of collector species was significantly higher on the concentrate samples relative to the tails while depressant species were significantly enriched on the surface of the gangue phases in the tail samples. A detailed evaluation of the surface species representing the various reagents used in flotation scheme revealed a distinct competitive relationship between two of the reagents. The surface analysis identified that when used in concurrently, there appears to be a negative feedback resulting in a significant reduction in loading for several of the collectors on grains reporting to the concentrate. An evaluation of the effect of reagents on REE mineral in pilot plant is currently under way. Key words: Rare earth minerals, Flotation, Surface chemistry, TOF-SIMS, SEM-EDX

Feb 27, 2013

By A. Farnoud

Thousands of miners, construction workers, and truck drivers are exposed to diesel exhaust particles. Diesel Particulate Matter (DPM) is a probable human carcinogen and stringent occupational and environmental standards have been established or are planned worldwide. Modifications in fuels and diesel engine designs have reduced emissions, but may not be enough to comply with the tightest standards. Post-combustion aftertreatment devices are likely necessary for many engine operators. However, even the most common and well studied aftertreatment devices fail from time to time. The objective of this study was to design, construct, and test an electrostatic aftertreatment device to treat DPM. An electrostatic precipitator (ESP) was designed and constructed to capture DPM from diesel exhaust, and different configurations were tested to optimize its performance. DPM was produced by a 6 kW diesel-powered electric generator and directed to the ESP through a short section of galvanized steel pipe after the muffler. Number and mass removal efficiencies were measured with a condensation particle counter (CPC) and by sampling through a stainless steel cassette and collecting the DPM on Teflon filters. Particle size distributions were measured with and without control using a 6-stage cascade impactor. The experiments were performed with the engine running at idle and also at medium load. The results show that our first generation ESP provides 60 percent mass removal efficiency, and up to 80 percent number removal efficiency. Power consumption was generally low, about 20 to 30 watts, to achieve these levels of performance.

Jan 1, 2009

By Raymond P. Miller, David L. Monson, Robert A. Robinson

A geotechnical instrumentation program consisting of borehole extensometers and portable tape extensometer stations was effectively used to monitor concrete liner deformations and guide construction procedures during enlargement of a 75-year old Union Pacific Railroad tunnel in Wyoming. Enlargement involved excavation of the old concrete invert and placement of 5,941 feet of new concrete invert 6 feet lower in squeezing shales, fault zones and water-bearing sandstones. Instrumentation data were used to guide procedures for excavating the old invert, installation of temporary interior struts, underpinning existing liner walls, and placing the new concrete invert.

Jan 1, 1976

By Brian Fulcher

The Arrowhead Tunnels Project represents the final portion of a 70 km (44-mile) long water conveyance facility that will bring up to 28 m3/sec (1,000 ft 3/sec) of water into Southern California. The 13 km (8-mile) tunnelling project is well underway and consists of two, 5.8 m (19-ft) diameter TBM bores through extremely variable geological conditions. An extensive and essential pre-excavation drilling and grouting program was performed in all reaches of the Arrowhead Tunnels Project, located north of San Bernardino, CA. This program supported the advance of two hybrid hard rock TBMs though extremely challenging ground conditions under substantial ground cover and up to 27 bar (900 ft) of ground water pressure. The well known San Andreas Fault lies nearby and has greatly influenced the local geological conditions. This paper will describe the means, methods and materials used throughout the numerous phases of the pre-excavation grouting program. It will also describe many versatile, flexible and innovative drilling and grouting methods and equipment systems utilized to improve performance, save time and costs in constantly changing geological conditions. Considerable lessons learned have been learned while overcoming some extremely formidable ground conditions and safely advancing the tunnels.

Jan 1, 2008

By Paul Eger

The use of wetlands to treat mine drainage has become increasingly common, particularly as more information is available on their operation and construction. However, the lifetime of each system is still, at best, an estimate. Treatment lifetime depends on the types of processes that provide the majority of the metal removal. Anaerobic systems (vertical flow systems) rely primarily on sulfate reducing bacteria, which reduce sulfate to sulfide and generate alkalinity. Metals can be precipitated as sulfides, and acidity is neutralized. These systems can remove over 90% of the metals and increase pH from around 4 to over 7. The bacteria will remain active as long as the system remains anaerobic and contains an adequate supply of sulfate and small chain organics. Although estimates of lifetime made on the total carbon in the system suggest that lifetime should exceed 20 years, data from field and laboratory studies show that the rate of sulfate reaction decreases with time, and that after several years rates decreased substantially. To maintain acceptable treatment, either additional organic material must be added or the total metal and acid load to the system would need to be reduced substantially. Aerobic systems (overland flow wetlands) can effectively remove metals from neutral mine drainage by reactions with organic material in the substrate. Over 90% of the copper and nickel have been removed in aerobic systems treating mine drainage in Minnesota. The primary removal processes in these systems include adsorption, ion exchange and complexation, which are finite; removal will cease unless new removal sites are generated. Two wetlands built in Minnesota have been successfully treating mine drainage for 12 years. At one of the wetlands, the annual production of new removal sites has been estimated to be equal to the annual metal input, and, as a result, metal removal should theoretically continue indefinitely.

Jan 1, 2005

By R. D. Williams

In spite of the increasingly polarized and politicized view of climate science and climate change in the United States, many of the principles behind the ?theory? of Anthropogenic Global Warming (AGW) or Global Climate Change (GCC) are in fact firmly established both in fundamental physics and detailed observations and are widely accepted elsewhere. The discovery of the earth?s ?greenhouse effect? dates back nearly 200 years to the work of French mathematician and physicist Joseph Fourier in 1824 and 1827. In 1872, John Tyndall an English physicist and mountaineer, described the capacity of various gasses to absorb radiant heat. He identified water vapor and carbon dioxide as the principal ?greenhouse? gasses. The work of Fourier and Tyndall was the foundation for the theory that increasing carbon dioxide (CO2) in the atmosphere might be responsible for an increase in global temperatures developed by the brilliant Swedish chemist Svante August Arrhenius in 1896. This was backed up by the additional work of Gilbert Callendar in the 1930s, and Gilbert Plass, Hans Suess and Roger Revelle in the 1950s. There is little scientific dispute about the physics by which this occurs: carbon dioxide in the atmosphere absorbs long wave radiation that would otherwise escape into space, thus warming the lower atmosphere and respective temperatures worldwide. The Intergovernmental Panel on Climate Change (IPCC), approximately 2500 climate scientists from around the world, has concluded that increases in carbon dioxide resulting principally from the burning of fossil fuels are responsible for most of the continuing increases in global temperatures (IPCC, 2007). NASA?s Goddard Institute for Space Studies (GISS) states; ?The ten warmest years all occur within the 12-year period 1997-2008? (GISS, 2009). 2009 was the second warmest year on record and 2010 was tied with 2005 for the warmest year on record (GISS, 2010, 2011). The science is in fact settled; the earth has not cooled since 1998 as some have claimed. It continues to warm as evidenced by not only surface temperature records but also ocean temperature records as well as changes in physical and biological systems (IPCC, 2007).

Feb 27, 2013

By William H. Langer

Large amounts of limestone fines co-produced during the processing of crushed lime-stone may be useful in the sequestration of carbon dioxide (CO2). Accelerated weathering of limestone (AWL) is proposed as a low-tech method to capture and sequester CO2 from fossil fuel-fired power plants and other point sources such as cement manufacturing. AWL reactants are readily available, inexpensive and environmentally benign. Waste CO2 is hydrated with water to produce carbonic acid. This reacts with and is neutralized by limestone fines, thus converting CO2 gas to dissolved calcium bicarbonate. AWL waste products can be disposed of in the ocean. Feasibility requires access to an inexpensive source of limestone and to seawater, thus limiting AWL facilities to within about 10 km (6 miles) of the coastline. The majority of U.S. coastal power-generating facilities are within economical transport distance of limestone resources. AWL presents opportunities for collaborative efforts among the crushed stone industry, electrical utilities, cement manufacturers and research scientists. There is a concern that CO2 generated from human activities is contributing to climatic and environmental changes. Approximately one-third of anthropogenic CO2 emissions come from burning fossil fuels to generate electricity. Each power plant is capable of emitting several million tons of CO2 annually. A variety of other industrial processes, such as cement manufacture, oil refining, and iron and steel production, also emit large amounts of CO2. The level of atmospheric CO2 can be reduced by capturing CO2 from point-source emissions and storing or sequestering it in isolation from the atmosphere (U.S. Department of Energy, 2003). In 1999, G.H. Rau and K. Caldeira proposed a geochemistry-based method that is referred to as accelerated weathering of limestone (AWL) in a paper titled ?Accelerating carbonate dissolution to sequester carbon dioxide in the ocean ? geochemical implications.?

Jan 1, 2009

By F. Hassan, M. A. Arafa

At El-Gedida iron ore deposits there is a block of about 30million tons neglected due to its higher sulfur content due to the presence of barite gangue minerals. From this bluk by magnetic separation dual concentrates of high grade iron concentrate (~65%Fe and total Sulfur of 0.26%) and the second concentrate is barite of (60.87% BaO and total impurities of less than 3%).

Jan 1, 1999