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By James J. Graham

Uravan, Ambrosia Lake, Gas Hills and South Texas are all historic names in US uranium. These mining areas supplied the uranium that brought the United States into the nuclear age during the 1960s, and fueled the birth of nuclear energy for peaceful uses — a promise of nearly limitless, clean energy for the world’s future. That promise still exists today, but it is hard to hear over the rhetoric of environmental activists and politicians. Nuclear power offers dependable electricity with limited environmental impact at stable prices. Nuclear power releases no greenhouse gases or particulate matter into the atmosphere. High level nuclear waste (HLW), although long lived, is readily controlled and compact. In the United States, generating 1 billion kWh of electricity with coal produces 47 kt (52,000 st) of solid waste (ash and sludge), compared to 3.6 t (4 st) of HLW produced by nuclear.

Jan 1, 2002

The National Mining Hall of Fame will hold its 13thAnnual Induction Banquet during MINExpo International 2000 in Las Vegas, NV. The gala black-tie (optional) event will honor eight legendary leaders of the mining industry. The event will take place at the Las Vegas Hilton Hotel on Sunday, Oct. 8. The induction ceremonies will salute mining greats elected by the board of governors from a list of nominees submitted by mining industry partners and the public. The members of the Class of 2000 will join 151 other inductees enshrined in the Mining Hall of Fame in Leadville, CO. The evening will begin at 6 pm with a cash bar reception followed by the banquet and program at 7 pm. Keynoting the banquet program will be Harrison (Jack) Schmitt. He was the geologist/astronaut of the Apollo 17 mission to the moon in 1972 (see related story on page 26). And he is the only scientist to “kick rocks on the moon.” Schmitt is also a member of the Mining Hall’s board of governors. Schmitt was also the keynote speaker at the First Annual Induction Banquet in Denver, CO in 1988.

Jan 1, 2000

By J. G. Davis

The St. Peter Sandstone is typically a well-sorted, friable, ultra-pure, fine- to medium-grained, quartzose sandstone with silica content higher than 99 weight percent in places. The sand grains are well-rounded, highly spherical and characteristically frosted. Their size typically varies from 2 millimeters diameter (No. 10 U.S. Standard Sieve Series size) to less than 0.08 millimeters diameter (No. 200 U.S. Standard Sieve Series size). A freshly exposed surface of the formation is commonly white with shades of pink and green. Weathered surfaces are a dirty gray or brown and are case-hardened at many localities. Bedding is characteristically indistinct, and the formation usually appears massive throughout. The rock is cross-bedded and ripple-marked locally. The formation is generally porous, permeable and rarely fossiliferous in Missouri. The St. Peter is continuously present in the subsurface in the northern half of the state and along the southeastern edge of the state. The St. Peter crops out in a narrow band that starts in western Montgomery County and runs southeastward, along the Missouri River, to just west of St. Louis and continues south, just west of the Mississippi River, through Scott County. The outcrop belt varies from less than one mile wide to over ten miles wide, and it is over 150 miles in length. The formation dips into the subsurface radially away from the outcrop band. A notable isolated outcrop occurs in Lincoln County to the north of the main outcrop band. The St. Peter is discontinuously present in the subsurface along a band in the west-central portion of the state. It is not present at the surface or in subsurface in the remainder of the state. The formation averages 80?100 feet thick. There is an estimated 3.8 trillion short tons of St. Peter in Missouri. Sieve analyses on drill cuttings indicate three subsurface locations in northeastern Missouri where the St. Peter is greater than 10 percent by weight of sand falling in the 20?40 U.S. Standard Sieve Series size range. The St. Peter was first produced in Missouri in the 1870s for the manufacture of glass. Since that time it has been used as a paint additive, filler material, polishing compound, filtering media, and recently it is commonly used as a fracture proppant in oil and gas wells. The St. Peter is currently quarried and produced in Missouri from four sites located in St. Louis, Jefferson and Perry counties. In the same area there are at least nine abandoned historic mine sites.

Feb 27, 2013

By Michael Lenz

Predictive maintenance technologies including vibration analysis, tribology, infrared thermography, ultrasonic detection, and electrical measurements have been applied to large electric mining shovels. The predictive program was initiated on the P&H Model 2300 and 4100 electric shovels. The utilization of these technologies has shown the potential for improving electric mining shovel availability and minimizing maintenance costs. Predictive technologies provide the tools to assess machinery condition. Availability is enhanced by the condition based planning of component replacement. Maintenance costs are minimized by focusing resources through condition based prioritization.

Feb 24, 1997

By J. Piper

Markets and Production Beryllium (Be), an extremely light metal, is used in many specialty applications. It the lightest element in Group 2A of the periodic table, with a specific gravity of 1.85 gm/cc, and a high melting point of 12850C (Calvert, 2004). The functional properties of beryllium are stiffness, strength, dimensional stability, resistance to corrosion from acids, and electrical and thermal conductivity. The ability to reflect neutrons and transmit x-rays, makes beryllium irreplaceable in uses such as precision optical components, inertial guidance systems, and in nuclear reactors (Anon, 1993). Beryllium is used in Cu alloys to strengthen and reduce corrosion in copper wire, and in lightweight oxide ceramics that are used as heat sinks, and as electrical insulators. The market revenue of beryllium can be broken down into the seven major groups below, and are plotted on the pie chart in Figure 1 (Anon, 2005). 1.) Telecommunications & Computer 2.) Magnetic & Optical Data Storage 3.) Aerospace and Defense 4.) Automotive Electronics 5.) Industrial Components 6.) Appliance, and 7.) Other.

Jan 1, 2007

By G. Tiravanti

A recurrent concern in mining operations is how to deal with the large volumes of fresh water used which in turn generates large volumes of effluents that have to be treated. Water treatment can focus in one of two main strategies: treat the effluent as it is produced, or use a simulation tool to optimize water use in the process and reduce volume of effluents, contaminants concentrations, operational costs, and so on. This article shows a successful tool developed in Matlab-Simulink® that allows modelling a mining process and simulating potential improvements to evaluate the results. This tool has been proven in Cu-Mo operations and recently it has been used in poly-metallic operations. This article reviews the 4 Key Steps required to achieve our goals: a) Elaboration and verification of the mining Operation?s Block Diagram, based on a field survey; b)Model construction and input flows and qualities in selected streams; c)Model Validation and Simulation of new alternatives like recirculation, changes in reagents and dosage, partial treatment, flows merges/separation, and others; d)Development of the Optimal Solution which consists on determining the CAPEX and OPEX.

Feb 27, 2013

The propensity of coal spontaneous combustion can be evaluated using various laboratory testing methods such as R70 adiabatic tests, thermal gravimetric analyzer (TGA) and critical self-heating temperature (CSHT) methods. Each of the methods has its unique characteristics and index for classifying the propensity of self-ignition of coals. Accountable relationships among the propensity indices of different methods should be established. Using the newly established R and TGA testing setups in our ventilation laboratory, samples from US coal mines have been collected and tested. 70 The TGA is a relatively new quantitative method. A test can be conducted in a relatively short time. The temperature and weight of the sample can be measured with high precision and then used to determine the activation energy of the coal which is a good indicator for potential of self-heating. Under a specific experimental design, the TGA technique could perform the proximate analysis for determining coal quality parameters (e.g., moisture, volatile matter, fixed carbon and ash content). These parameters can be used in an empirical equation for assessing the potential of coal self-ignition. The trend of activation energies determined using TGA techniques and adiabatic tests are reasonably consistent with each other. As a case study, a comparative analysis of these two methods for determining activation energy was made on coal samples collected from Indiana. The kinetics of the spontaneous combustion mechanism has been explained. If the functional groups of a coal are easier to be activated with a small amount of activation energy at a relatively low temperature, the coal will has a higher potential of self-heating. With the kinetic and coal quality parameters determined by the TGA setup, it has been found that the coal with low potential of self-ignition has low self-heating rate, high activation energy and high minimum self-heating temperature.

Jan 1, 2012

By Alan Weakly

The Powder River Basin (PRB) of northeastern Wyoming and south-central Montana is the largest strippable reserve of compliant coal (0.6 or less lb of sulfur per million Btu) in the United States. In mining parlance, it is the Mother Lode! Wyoming’s portion of the Basin provides one fifth of the coal produced in the United States annually, and the state has been the nation’s top coal producer for the past six years. Based on 1993 production statistics and estimated strippable compliance coal reserves, Wyoming may remain the nation’s top producer for the next 76 plus years. Past articles on the PRB have focused mainly on production. After living and working in the Basin for the past five years, I have developed an appreciation for the area and its major industry that transcends size and production data. In the fall of 1993, MINING ENGINEERING’s publisher and I decided to present a series of articles that would cover many other aspects of the Basin. Ten topics were outlined, and specific individuals, selected for their knowledge and experience, were asked to contribute articles about their specialties. Although Montana has four large mines producing coal from the PRB, this series of articles will concentrate on the Wyoming portion of the Basin.

Jan 1, 1994

Your assessment of the minerals business. The global mining industry is strong. I am convinced it will continue meeting the mineral needs of the world population for the foreseeable future. Two developments have greatly enhanced the industry’s ability to produce low-cost minerals. Technological innovations have resulted in increased productivity. And there has also been a dramatic expansion of the number of favorable countries in which to explore and mine. Capital expenditures have flowed to the low-production-cost mines and development projects as well as to the exploration projects and stable countries having the best potential for valuable mineral discoveries.

Jan 1, 2000

By C. C. Hamilton, G. R. Lane

Traditionally, mineral sands are evaluated by preparing several mineral products using a combination of heavy liquid-, magnetic-, and electrostatic methods. Whole-rock assays (WRA) are then conducted on ilmenite, rutile and zircon products in order to determine trace element contents, which may affect project feasibility. Combined methods can be time consuming, expensive and even outdated due to the use of banned and toxic chemicals such as clerici solution. Coupled with large field-sample quantities, these procedures can potentially introduce unacceptable sampling and related errors. Modern mineralogical analysis techniques can provide complete mineralogical inventories on a single THM product, reducing the amount of processing involved in satisfactory characterization of early exploration samples. A small exploration sample can be processed to produce a small THM concentrate using readily available gravity/density methods. In turn, the THM product is submitted for Whole Rock Analysis (WRA) and mineralogical inspection by X-ray diffraction (XRD), and microscopic evaluation. Modal mineralogy and textural data can be determined using optical methods, automated image analysis, and scanning electron microscope (SEM) based systems. Benefits of automation are reproducibility and the capability of rapidly analysing thousands of particles as opposed to manual optical methods. Automated systems include the use of Automated Digital Image Analysis (ADIS), and SEM-based systems such as the Mineral Liberation Analyser (MLA) and QemSCAN. For detailed mineral chemistry, microanalysis techniques ranging from electron microprobe (EMPA) to Secondary Ion Mass Spectrometry and Laser Ablation Mass-Induced Coupled Plasma-Mass Spectrometry (LAM-ICP-MS) are used. Examples of these automated and analytical methods are presented. ADIS at SGS-Lakefield Research uses optical characteristics to identify and measure mineral species in THM samples; rutile, pseudorutile, ilmenite and leucoxene can be distinguished. Analysis of a single THM product provides bulk modal mineralogy and grain size distribution of particles and the individual mineral grains. Textural information is also obtained detailing mineral associations as well as degree of alteration. Where textural and chemical resolution renders mineral identification ambiguous, SEM-based methods offer better resolution. Examples of this ambiguity are shown in this paper, which leads to QemSCAN as the preferred method where within-grain variability is concerned. Sampling and measurement strategies are followed to meet study objectives, providing a value-added framework for a sequential, cost-effective strategy, which will meet due diligence and bankable accreditation criteria. Studying a THM product by electron microprobe and LAMICP-MS may reveal potential fatal flaws related to mineral chemistry. Low detection limits in the range of 200 to 500ppm are possible using electron microprobe analysis for suitable matrixes (U, Th in zircon). For the detection of ultra low level elemental contaminants, LAM ICPMS is the most accurate method of evaluation. Elements including U, Th, La, Ce, Nb, and V in Ti-minerals can be determined down to 50 ppm.

Jan 1, 2005

By E. Farrokh

Estimation of the cutter life and cost is a part of evaluating performance for a hard rock TBM in any project. Various approaches has been proposed for calculation of disc cutter life in various rock types based on machine specifications and rock strength and abrasivity. Cutter change time is a parameter that is used in some of the estimates and is defined as the average time required for changing a cutter on the cutter head and cutter life is the number of cubic meters of excavated rock per each disc cutter. Analysis of cutter life information of several tunnel projects from around the world has revealed that the published models for estimation of cutter consumption require some revisions to offer a more accurate prediction. The preliminary analysis of data shows that the average cutter change time is approximately 66 minutes for different cutter sizes and there is a minimal difference between corresponding cutter change times of the large (e.g. 19 or 20 in) versus smaller cutters (e.g. 15.5 to 17 in). This paper reviews the available and published cutter life data from various projects. It also introduces new models for estimation of cutter life and cutter change time as part of TBM down time and utilization analysis.

Feb 27, 2013

By D. Küster, G. Franken, P. Schütte, J. Vasters

The CTC (Certified Trading Chains) mineral certification system has been piloted in Rwanda since late 2008. CTC project implementation is jointly driven by the Federal Institute for Geosciences and Natural Resources (BGR) and the Rwanda Geology and Mines Authority (OGMR), in cooperation with other national stakeholders. Five Rwandan mineral producers participate in the CTC project with their flagship mining concessions. Based on independent third-party audits, CTC certifies supply chain due diligence measures of these companies engaged in the artisanal mining sector through on-the-ground assessments of mining conditions, transparency, as well as mineral origin and traceability. The CTC system thus allows responsible mineral producers and their clients to verifiably demonstrate supply chain due diligence and good governance in conflict-affected and high-risk areas.

Jan 1, 2011

By U. Richter

Conveyors are a highly effective means of transporting material over long distances. Recently there has been a trend toward long conveyor systems with high capacity single flights. These conveyor systems are an efficient alternative to costly truck fleets. Also with deeper mines, the use of diesel driven trucks becomes more difficult. Another trend is in underground mining, where conveyors are an efficient alternative to drift hoists or dedicated rail systems.

Jan 1, 2012

By W. P. Diamond, S. L. Cario, F. Garcia, J. D. Byars, T. P. Mucho

The National Institute for Occupational Safety and Health (NIOSH) has been conducting research at a Pittsburgh Coalbed longwall mine to evaluate and optimize bleeder ventilation and gob gas venthole longwall methane control systems. Gas flow into these two methane control systems was investigated using a combination of Sulphur Hexafluoride (SF6)tracer gas studies and gob venthole pressure monitoring experiments. The insights gained from this research has facilitated the development of a longwall subsided strata methane control system conceptual model. This model provides the basis for design suggestions to increase the efficiency of the gob gas venthole system to permit the bleeder ventilation system to become a "safety net" for methane control.

Jan 1, 2000

By V. Rajaram

Rock reinforcement systems are used in open pit and underground mines to stabilize the rock mass in-situ and provide safe working conditions. Significant progress has been made to date in the design and implementation of rock reinforcement systems to accommodate bad rock conditions and larger excavations. However, the rationale for the design of rock reinforcement systems remains essentially the same and can be categorized into three groups, namely 1. to create a beam of competent rock in stratified formations, 2. to resist sliding motion in jointed rock, 3. to passively support the superincumbent loads in highly stressed ground. Case histories of the rock reinforcement sys¬tems that illustrate these design approaches will be presented in this paper.

Jan 1, 1983

By M. Z. A. Bakar

To investigate the differences in the radial drag pick cutting performance in dry and saturated sandstone, a suite of linear rock cutting test was performed using linear rock cutting machine (LRCM). Experimental results of 50 data passes, incorporating 350 data cuts were used to compute cutting, normal and side forces required for determination of other performance related parameters. Although the forces required to cut the dry and saturated rock were in congruence for most of the spacing and depths of cut combinations; but the overall averaged cutting and normal forces for saturated rock cutting were found to be 9.9% and 9.4% respectively higher than the dry rock cutting. The increase in the overall averaged forces was attributed to strength variability of one of the saturated block affecting the overall forces. The side forces experienced a negligible drop in saturated rock cutting. An increase of 28% and 9% in the actual and nominal specific energy values respectively was also recorded when cutting saturated rock as compared to the dry rock cutting. The increase in saturated rock specific energy is attributed to production of large amount of fines and few large sized chips directly contributing towards increase in specific energy. The optimum s/d ratio for dry rock tests was found to lie between 6 and 8 whereas for saturated rock cuts this value lied between 5 and 9.

Jan 1, 2012

Oil sands processing generates huge volumes of slurry, known as tailings, that is being stored in tailings ponds. The volume of produced tailings is a very important factor in oil sands surface mine planning, because the available area for dam construction is limited to the lease areas. On the other hand, oil sands operators cannot leave mine sites without reclaiming the tailings ponds. Since most of the reclamation material is generated in either oil sands mining or processing, it is reasonable to include reclamation material requirement as part of long-term mine planning. In this paper, an integrated optimization framework is proposed to maximize the net present value (NPV) of the produced oil sands, with respect to tailings capacity constraints and reclamation material requirements. A mixed integer linear programming (MILP) model is developed to find the optimal solution for long-term mine planning problem. A sample bitumen processing flow sheet is used to formulate the volume of produced tailings, based on Clark hot water extraction method. To verify the proposed model, it is coded in Matlab and run using CPLEX. Run results for real-case oil sands dataset show that the optimal production schedule meets material requirements for reclamation, tailings volume is within tailings capacity range in all periods and the production schedule follows the predetermined horizontal direction.

Feb 27, 2013

By Dan Armour

Bolting solutions traditionally offered only wet drilling or dry drilling options; each with advantages and disadvantages. Joy Mining Machinery has developed a Mist Drilling System that incorporates the best of both types of drilling. Compared to wet drilling, mist drilling offers as much as a 90% reduction in water use. As a result, floor and roof conditions are tremendously improved. This offers a safer and more comfortable work environment for operators. Mist drilling can offer a significant reduction in noise levels compared to dry drilling and in recent trials, bit life has been greatly improved. Holes are cleaner and operators experience less exposure to respirable dust.

Jan 1, 2005

By N. Aouad

The deployment of large machinery for low cost, bulk surface mine production operations has resulted in high-impact shovel loading operations (HISLO). In extreme cases, shovels load large dump trucks with 100-ton (or more) passes generating high-impact forces under gravity. HISLO generates high-frequency shockwaves that cause severe truck vibrations exposing operators to whole body vibrations (WBV). Current research study in this area has established that the vibration levels affecting the operator?s seat, lower-back, lumbar and cervical regions fall within the extremely uncomfortable zone compared to the ISO 2631 comfort zone. These results pose health threats to truck operators over long-term exposure to these vibrations. In this paper, the authors will examine engineered solutions to mitigate these health threats.

Jan 1, 2011

By William R. Yernberg

The combined 80th Annual Minnesota Section of SME Meeting and 68th Annual University of Minnesota Mining Symposium was held April 17 and 18, 2007, in Duluth, MN. About 350 mining industry professionals attended the conference, including engineers, executives, mining managers and suppliers from the United States, Canada, Australia, Finland and Brazil. This year’s theme was “Consolidation – Growth – Technology.” The 80th Annual Minnesota Section of SME meeting included concurrent technical papers sessions, a keynote session that featured two distinguished speakers and a general managers session in which taconite mine operators provided updates on their operations. The Minnesota Section meeting also offered an SME short course titled “Control the Feed, Control the Mill.” More than 50 individuals at-tended the short course.

Jan 1, 2007