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By Marion Loomis

Environmental regulation is an ever growing cost to the mining industry. Requirements for such items as air quality modeling, hazardous waste disposal, selenium concentration in water and sagebrush planting consume more of the mining industry’s resources each year. The mining industry is willing to make the necessary financial commitments to assure that the air, land and water resources are adequately protected and restored. However, it is sometimes difficult to explain to management and stockholders why money should be spent on a specific issue when science and common sense indicate it is being wasted. Common sense and sound science should dictate how mining is regulated.

Jan 1, 1994

By D. Washington

The US economy and the demand for nonfuel minerals grew at lower rates in 1995 than in 1994. Demand for major metals, such as aluminum, copper and steel, was mixed but relatively stable. The building industry, including highway construction, helped to support modest overall growth in demand for industrial minerals. The value of processed materials of nonfuel mineral origin produced in the United States during 1995 was estimated to be $395 billion, an increase of almost 10%compared with 1994 (Fig. 1). The estimated value of US raw nonfuel minerals production during 1995 was $38billion, about 7% more than in 1994. The value of US minerals production has increased in 30 of the last 35years.

Jan 1, 1996

By S. Dixon

The Phelps Dodge - PD/PERI Heap2D Model is a phenomenological stockpile leaching model that has been used to investigate the best operating practices for leaching chalcocite. The model was used to investigate the interrelationships of raffinate application rate, aeration rate, raffinate iron grade, acid cures, lift height, crush size, bulk density, air injection spacing and raffinate drip emitter spacing.

Jan 1, 2006

By S. Strömberg, A. Jokilaakso

Two complex copper concentrates and one arsenical nickel concentrate were oxidized in simulated flash smelting conditions using a laminar-flow furnace. The concentrates contained tetrahedrite as Sb-bearing mineral and arsenopyrite and gersdorfite as As-bearing minerals. At high temperatures and low oxygen potentials, Sb tended to vaporize, but with high oxygen potentials it was captured in mixed oxide phases with copper and iron. Arsenic was found to follow antimony in copper concentrates, although with less sharp contrast between low and high oxygen potentials. In the nickel concentrate studied, arsenic was found to vaporize from the gersdorffite particles and, subsequently, condense on the other particles.

Jan 1, 1998

By R. L. Zick, D. C. Finn

Introduction The high-density sludge process was originally developed by Bethlehem Steel Corp. for use on acid mine drainage (AMD) and diluted waste pickle liquor discharges requiring continuous chemical-treatment. This work began in the early 1970s and was first put into practical use around 1973. To date, there are approximately 15 operating systems that have been installed to treat mine drainage in the United States. In addition, there are another 10 systems installed outside of the United States. The dense-sludge process is an innovative and improved method for treating acidic metal-bearing streams in a manner that minimizes the volumetric generation of sludge for disposal. The technology utilizes a sludge-recycle process that forms particles with a low affinity for water. These particles are unlike conventional metal hydroxide solids that contain tightly bound interstitial waters. Typical acid mine drainage streams contain high sulfate concentrations that combine with calcium ions in lime-based treatment systems to form gypsum crystals. Compared to the form generated in conventional lime treatment systems, the physical form of the gypsum is radically altered when the dense-sludge process is utilized. The characteristics of the metals particles are also changed in this process, as the metal hydroxides are converted to metal oxides. The dense-sludge particles settle faster, dewater more readily, are more easily pumped and hold much less water than conventional precipitates. In some cases, because the metal content of the sludge is more concentrated, it can be economically recovered. In general, the conventional and dense-sludge treatment processes are very similar. The changes required to implement the dense-sludge process are minor, and, typically, much of the existing equipment can be utilized. The net results of the process are: reduced operational costs associated with sludge generation, improved process control (particularly pH control), reduced gypsum deposition (i.e., less scaling) on system components and reduced sludge generation resulting in less return water for treatment. Despite the relative simplicity of the process, the application of the technology requires careful discrimination, and the "experience factor" for implementation is an important consideration that should not be over looked.

Jan 1, 2000

By Bruce Hebblewhite

This paper focuses on the recent achievements and practices developed through the Minerals Tertiary Education Council (MTEC) initiative of the Minerals Council of Australia (MCA), in conjunction with the three partner universities involved in mining engineering education – University of New South Wales (UNSW), West Australian School of Mines, Curtin University (WASM), and University of Queensland (UQ). The collaboration between these partner universities and industry has led to the development of shared course material, cross-institutional teaching arrangements, and development of a number of flexible, distance-based delivery programs. The paper will then move on to future initiatives. Importantly, the exciting challenge is the future initiative planned to cement this collaboration by the formation of a “virtual” national school of mining engineering – Mining Education Australia (MEA). This will provide a common 3rd and 4th year program to all three universities from 2007, involving innovative teaching and learning arrangements, greater student exchange potential and a more significant input by industry into the education process. Such an initiative is not without its challenges, and has a long way to go, before becoming a reality. However, it offers greater attractiveness and marketing potential to prospective students, as well as economic efficiencies, whilst delivering a better quality, and hopefully greater quantity of graduates to industry. It can also form a launching platform for a much greater level of international collaboration, through a proposed International Mining Education Network (IMEN) which is currently being floated amongst a number of international educators.

Jan 1, 2005

By Richard Gertsch, Jack Eloranta, Leslie Gertsch

An ongoing research program is characterizing the ore qualities that most affect mine and mill processing of iron. Current practice uses assays of magnetic iron and silica, but additional qualities are needed for advanced process control. If additional qualities can be measured from core, blastholes, or process samples, they can be modeled and controlled similarly. What qualities, other than assays, hinder or facilitate beneficiation at each processing step, and how can they be measured in the mine/mill ore stream? This paper describes preliminary determinations of the effects of ore chemistry, hardness, blasthole drill performance, fragmentation control, and grindability on mill performance.

Jan 1, 2005

By Felicity Lloyd, Stuart Kearns, Roger McLimans

The metamorphic terrane of southwestern India is a geological environment containing ilmenite source-rocks, transport drainage systems, and resultant beach sand deposits that contain altered ilmenites greater than 60wt% TiO2. As such, this environment provides a geological laboratory, from source to deposit, for the investigation of ilmenite origin, alteration, and geochemical character. Ilmenite samples from potential source rocks, river sands, and beach sands all show degrees of alteration and a variety of alteration textures (iron leaching) producing leucoxene (here defined as >70 <90wt% TiO2) and progressing to rutile (here defined as >90wt% TiO2). Distinct alteration textures are specific to different source rocks and are used together with trace element geochemistry as provenance criteria. Ilmenites are classified on the basis of their trace element content. In India, the ilmenites are classified principally according to the Mg, Nb, and Mn content and this signature defines potential source rocks, even where the ilmenite is altered to a TiO2 content of 70wt%. The trace element data may fingerprint source rocks whose ilmenite is more prone to iron leaching and that criterion has application in exploration for higher-grade ilmenites.

Jan 1, 2005

By Tony Peach

Project Description The Ok Tedi Mine is located approximately 18 km east of the Papua and New Guinea-Indonesia border, on the southernmost extremity of the Star Mountains Range, it is situated almost equidistant from the north and south coastlines. The headwaters of the Fly River system are in the Star Mountains. The open pit mining activities are on Mt Fubilan with a (pre-mining) elevation of 2,095 metres (6,871 Feet) in the Western Province. The mine is in an area characterised by very steep topography and dense tropical rainforest. The pit has been free draining but will cease to be so in the first quarter of 2009. Ok Tedi Mining Limited (OTML) required a drainage tunnel to be driven under the mine, if possible before free drainage was no longer possible. The tunnel was required to be at least 5 m in diameter and 4,200 m (13,776 ft) long, with a possible extension of 1,100 m (3,608 Feet) if the mine decided it was required for additional drainage and underground exploration. The tunnel is being driven up grade at 0.67%, and will be connected to the pit by the raising boring of two 1.1 m (3 Ft. 6 In.) diameter shafts from the tunnel level 250 m (820 Feet) below to the pit. In Tabubil, the adjacent township at an elevation of 640 m (2,100 feet), air temperatures range from a mean at night of 20 (68°F) degrees centigrade to a daytime aver-age of 27 (81°F) degrees. Extremes of 12 and 39 (54°F?102°F) degrees centigrade have been recorded. Rain falls, on average, 339 days each year and totals 8,000 mm (315 inches), and have been known to approach 12,000 mm (472 inches) making the area one of the wettest places on earth. The portal site is at an elevation of 1,200 m or 4,000 ft and the air temperatures are a little cooler and the rainfall a little greater. Access to the mine is by air for personnel and light freight and by ship for heavier goods and materials. The port is at Kiunga on the Fly River 153 km from the portal site. The program for the project was tight, the decision to purchase the required TBM was made in July 2007 and the final decision to go ahead with the construction of the tunnel was made in November 2007.

By K. Mondal

A macroscopic approach integrated with microscopic analyses for wettability characterization is presented. Wetting depends on 1) Contact between the dust and the fluid droplets, 2) Wettability of the particles by the wetting fluid, and 3) Wettability rate (due to low contact times). The goal of this paper is to show that the wetting rate is a significant factor in dust control. Samples from the roof, three different horizons of the coal seam and the floor were pulverized to less than 25 µm. Experiments were conducted with known wetting fluids to correlate surface tension and equilibrium wettability. Further analyses were performed in terms of surface charge (zeta potential), particle size, mineral composition, elemental composition, and quartz content. The surface tension reduction was also achieved by the use of chemicals and/or altering the temperature of the water. Two methods were used to evaluate wettability rates: a) near real-time comparison of wettability rates, and b) comprehensive evaluation of the intrinsic wettability rates. The data obtained provides meaningful insights towards the design of engineering controls for an economical solution to dust control in coal mines.

Jan 1, 2012

By Donald W. Gentry

This section deals with one of the most fascinating aspects of mining the evaluation of mine investment opportunities. Be-fore proceeding further, it is important to clarify the meaning of some fundamental terms used frequently in the text. 6.0.1.1 Mine Valuation vs. Evaluation The words "valuation" and "evaluation" in a mining context are often used interchangeably. However, for the purposes of this section, a distinction is made between the two terms in accordance with commonly accepted practice. The word valuation in a mining project context has the rather narrow meaning of placing a dollar or other currency value on the worth of the project as a whole. In other words, the value of a mining project refers to a measure of the desirability of ownership of that property. As such, the major item of interest is, "what is the mine worth?," or `what is the value of the mine?" The value of a mining project may actually be determined in the marketplace at any specific point in time, or it may be estimated by one of several methods. The topic of mine valuation is discussed in more detail in Chapter 6.1. The word evaluation in a mining project context connotes the broader meaning of determining the numerical values of all

Jan 1, 2008

By K. Sasaki

Diffusion phenomena in mine airways are important to trace gas and dust introduced into mine ventilation flows. Authors have carried out tracer gas measurements to check mine ventilation using concentration-time curves measured in mine airways, however dispersion mechanism to enhance effective diffusion have not been cleared. A numerical model using discrete tracer points dosed into tube flow has been presented to simulate their movements in consideration of turbulent velocity profile and fluctuation. Numerical simulations have been carried out to predict distributions of dosed points in tube flows with turbulent velocity profile, turbulent intensity profile and Reynolds stress. The numerical simulation results show that a combination of turbulent velocity profile and fluctuation creates extremely large dispersion of points in longitudinal direction and concentration curve with long tail was observed. This dispersion by velocity profile and fluctuation contributes large effective diffusion coefficient compared with original diffusion coefficient dominating in uniform velocity fields. Furthermore, the effect of Reynolds stress on the concentration-time curves is discussed.

Jan 1, 2009

By H. Akbari

The ordinary Portland cement (OPC) is the key pozzalonic component of the concrete mix, widely used as the construction material world-wide. Billions of tons of OPC are used in the construction industry each year. However, calcinations of limestone and silica that produce OPC also produce almost an equal amount of CO2 during the cement manufacturing process. Thus, OPC production accounts for nearly 7% of all anthropogenic CO2 emission each year. The main objective of this study was to develop a geopolymer-based composite to be used as a substitute for OPC in concrete application to significantly lower the carbon foot print of the construction industry. A waste material produced during the coal combustion process was used as the main raw material for the geopolymer-based composite. It was mostly the non-metallic content of the F-type fly ash produced from the combustion of bituminous coal. The authors envisioned to extract some of the valuable metal oxides from fly ash prior to using the major non-metallic portion of the fly ash for geopolymer concrete application. The results obtained from this study exhibited that the compressive strength of the geopolymer concrete compares favorably with that of the conventional concrete prepared using the OPC.

Feb 27, 2013

By K. G. Kebkal, R. Bannasch

"Because the operation of tethered underwater vehicles in the deep ocean or under drifting ice areas is very complicated or impossible, the application of autonomous underwater vehicles (AUV) is preferred or even the only possible solution. However, this implies the possibility of a direct and real-time control over all AUV functions, which is only achievable with the availability of accurate positioning/navigation and a high-speed communication link. This paper presents a flexible bottom- or surface-based solution enabling high positioning accuracy of underwater objects (harvester, AUVs, bottom nodes); specifically, a multifunctional system that combines Ultra Short Baseline (USBL) transceivers and Long BaseLine (LBL) stations deployed at a large depth. Moreover, each baseline transponder is equipped with a high-speed communication device to provide the means for real-time AUV control based on the information about its current position, e.g. navigate it with direct commands and operating its actuators and other mechanisms. Moreover a communication link with a high data rate can provide valuable visual information from the operation area.Depending on how many nodes the LBL grid comprise has, target transponder positions can be estimated with an accuracy of several to tens of centimetres. The purpose of the paper is to present the experiments with all key elements of the multifunctional Hydro-Acoustic USBL-aided LBL Positioning and Communication System."

Sep 1, 2014

By Albert Adu-Acheampong

Fairmount Mineral&apos;s Maiden Rock underground sand mine historically delivered air to ventilate diesel-powered equipment at its working faces through high-resistance, 381-mm- (15-in.-) diameter PVC distribution lines. In support of plans for expanded production, three new, low-resistance ventilation design alternatives were analyzed. The study determined that adequate ventilation for expanded production was possible with various commercially available, high-volume/ low-pressure fans combined with a systematic layout of control structures. The recommended redesign was implemented in 2001, resulting in a significant increase in flow volumes and a noticeable improvement in the mine environment.

Jan 1, 2008

Basic parameters affecting the stability of foams have been studied. We used the thin film pressure balance (TFPB) technique of Scheludko and Exerowa (1959) to measure the surface forces in foam films stabilized with various frothers such as pentanol, octanol, MIBC, and PPG. The results were compared with the froth stabilities measured using the shake tests and the film elasticity calculated using the model developed by Wang and Yoon (2006). It was found that the froth stability is controlled by both film elasticity and surface forces (or disjoining pressure), the relative contributions from each changing with frother concentration and type.

Jan 1, 2006

By Alan Zeni

Blind shaft drilling equipment has not changed substantially since the 1970s. Since it resides in a niche market between conventional shaft sinking and raise boring, the relatively small demand has resulted in some stagnation of development. In the 1990s the technology found a larger foothold in foundation and deep piling work for civil construction. WIRTH GmbH from Erkelenz, Germany has been servicing this market for many years with pile top drilling rigs and tools. Frontier-Kemper Constructors, Inc. recently entered into an agreement with WIRTH to develop a new generation of large diameter blind drilling equipment more specifically aimed at mining needs. The, recently completed, DHI-240 is the first rig to apply the most recent technology. This machine made its commercial debut in the fall of 2008. A description of the technology and a short case study of the first project will be described

By Tim O’Neil

The earthmover tire shortage has been a case of bust and boom for the tire industry. Tire producers were unwilling to invest ahead of the mining boom. In their defense, though, the metals sector of the mining industry tends to be cyclic, tire manufacturers are not prescient. Until two years ago, low tire demand depressed prices. The incentive to invest in new, big-tire capacity was almost nonexistent, according to Prashant Prabhu, president of Michelin Earthmover Tire worldwide. “There has been very poor anticipation or a miscaluation of the amplitude of the (tire) demand on the part of just about everybody,” said Prabhu. What a turnaround. The earthmover tire market has grown by 30 percent over the past two years. Now there are not enough earth-mover tires and likely won’t be for the next two years. Goodyear said it was offering customers bias-ply tires when it could not supply enough radial-ply tires. Komatsu said it lost equipment sales because it could not provide the tires that customers requested. Volvo and Caterpillar said they are delivering some vehicles without tires, either promising tires later or leaving the customers – mine operators – to find their own rubber.

Jan 1, 2006

By L. M. Anisdahl

Ventiflex is a flexible ventilation duct system with a global market within mine and tunnel ventilation. The system is distributed in a wide range of qualities and dimensions. It is very important that ventilation systems are designed correctly in mines and tunnels. An incorrectly dimensioned system might result in bad air quality and too high costs. The objective of this study has been to assess some important design parameters for ventiflex comprising the friction loss factor for the duct wall itself, as well as the shock loss factors and the leakage factors for the different couplings systems. This has been obtained by carrying out a large scale experimental program on ducts with all the three different couplings: Velcro, zip and steel-ring. Pressure profiles and air flow rates have been measured, and based on these data the different factors have been calculated. The following results have been obtained: A friction factor l = 0,012 (K = 10) for the duct wall, a shock loss factor z = 0,0125 for velcro- and zip couplings, a shock loss factor z = 0,005 for steel-ring couplings, and a leakage factor f* = 0 mm2/m2 for all three coupling types. The latter result proves that no leakage is possible for a correctly installed duct with proper alignment. The results also confirm that ventiflex complies with class S, or better, according to the SIA-norm. However, whether ventiflex should be designed as class S, A or B according to the SIA-norm, depends on the particular application.

Jan 1, 2009

The MINER Act of 2006 mandated that all underground coal mines must install and maintain refuge chambers. Refuge chambers serve as a temporary shelter in case of emergency. Several factors affect the performance of a refuge chamber: heat production inside the chamber and introduction of CO when chamber doors are opened are two major factors. This study examines the CO purging process and to determine total air quantity and time necessary to lower the CO con-centration to safe levels for different inlet/outlet configurations using three-dimensional simulation technique. The study uses Reynolds Averaged Navier Stokes and continuity equations along with the spe-cies transport model assuming uniform air mixing. The heat transfer of any kind is neglected and the purging process is assumed to take place isothermally. The standard k-e model is utilized for simulating turbulence in the flow field. This research provides useful guidelines in developing an efficient strategy for purging refuge chamber. Keywords: Airlock chamber, Purging, Carbon monoxide, Turbulence

Feb 27, 2013