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By Russell E. Griffin

The current state-of-the-art of fire and smoke detection technology is reviewed from the standpoint of suitability for use in underground metal and nonmetal mines. Detection modes, fire signatures, and environmental considerations are included. Preliminary results of long-term in-mine tests are presented.

Jan 1, 1979

When xanthates or dithiophosphates are used as collectors in sulphide ore flotation, adsorbed species may be identified by gas chromatography of the volatile products formed during low temperature pyrolysis. For collector additions ,as low as 20 g/tonne of ore, pyrolysis of the flotation products usually gives' an olefin directly related to the particular xanthate or Aerofloat reagent used. The method is able to provide valuable qualitative and quantitative data relating to the extent of collector adsorption and the resulting changes in the hydrophilic or hydrophobic nature of the mineral surface.

Jan 1, 1974

By C. Özgen Karacan

Methane emissions from the active face areas and from the fractured formations overlying the mined coalbed can affect safety and productivity in longwall mines. Since ventilation alone may not be sufficient to control the methane levels on a longwall operation, gob vent boreholes (GVB), horizontal and vertical drainage boreholes, and their combinations are drilled and used as supplementary methane control measures in many mines. However, in most cases, the types of degasification wellbores chosen are decided based on previous experiences without analyzing the different factors that may affect this decision. This study describes the development of an expert classification system used as a decision tool. It was built using a multilayer perceptron (MLP) type artificial neural network (ANN) structure. The ANN was trained using different geographical locations, longwall operation parameters, and coalbed characteristics as input and was tested to classify the output into four different selections, which are actual degasification designs that US longwall mines utilize. The ANN network selected no degasification, GVB, horizontal and GVB, and horizontal, vertical and GVB options with high accuracy. The results suggest that the model can be used as a decision tool for degasification system selection using site- and mine-specific conditions. Such a model can also be used as a screening tool to decide which degasification design should be investigated in detail with more complex numerical techniques.

Jan 1, 2009

By Wayne N. Marchant

Introduction The issue of coal mining safety plays an important role in the United States' growing dependence on coal to supply its future needs. This article will address the federal government's role, principally the US Bureau of Mines, in meeting this challenging growth and demand while reducing the social and economic costs attributed to injuries and fatalities in underground mining. Some interesting facts and projections with respect to the nation's energy picture will be discussed. This includes the distribution of its reserves and the projected role of coal in the energy and economics of the nation's future. Underground mining will continue to be an important means of providing this coal. The author will discuss how the Bureau of Mines' research program addresses the problems of health and safety that grow out of the demand for more coal. Future projections First, a synopsis of salient facts and projections concerning the US's situation with respect to energy and the economy. Figure 1 depicts the relative quantities of recoverable energy reserves in the United States by their type. Most people are aware of the nation's use of oil. We hear a lot about natural gas. And we are aware of the controversy over the use of nuclear energy. But, while looking at Fig. 1, the question becomes, "Where will our fuel to meet the demand for energy in the future most certainly have to come from?" With 82% of the nation's recoverable fuel reserves being coal, the answer is irrefutable. Coal will be that source. Figure 2 is the present market for coal. It shows that 77% of the coal mined goes to supply electric utilities. Therefore, the coal industry as a whole is most sensitive to the trends and demands for electricity. It is less affected by what happens in other markets, such as export and direct industrial use. In fact, the coal industry is three times more sensitive to the electric utility market than to all other markets combined. Therefore, the trend in the demand for electricity must be examined. Electricity demand is expected to increase steadily over the next 15 years. It is projected to grow from its present 2.3 trillion kWh per year to 3.5 trillion kWh per year by the year 2000. The fuel to supply this increase in demand must come from somewhere. The question is "How much of this extra fuel will be coal?" Although the demand for electricity is predicted to increase, the demand for coal does not necessarily follow. Coal must maintain its fraction of the energy sources used for electricity generation if its demand is to increase at the same or greater rate as electricity. Except for a near-term dip in demand due to a slight increase in nuclear capacity, the domestic electric generation accruing to coal will go from 56% in 1985 to more than 60% in 2005. Thus, the predicted trend is for coal to become a larger part of the fuel mix for electric power generation. Similarly, looking at the most recent forecast for total coal consumption trends, it can be seen that for electric power generation alone, the coal industry must be able to supply an additional 316 Mt/a (348.5 million stpy) by the year 2000 (Fig. 3). It must be stressed here, though, that without significant improvements in mining safety, it can also be easily predicted that injuries and fatalities will increase in proportion to the increase in coal production. Will society consider that acceptable? This author does not believe so. Figure 4 examines the effect of coal prices on the price of electricity. The projections show that the already high proportion of fuel cost will become a greater fraction of the consumer price for electricity. Specifically in 1985, 36% of the price of electricity was the cost of the fuel. In 1995, 46% of the price of electricity will be the fuel cost. That implies that the price of coal will have an increasing influence on the consumer price for electricity. Thus, as coal is used more to generate electricity and as fuel becomes a greater

Jan 4, 1987

By P. Miranda, K. Le, G. Maes, R. Peters

"The Mount Milligan Mine, owned by Thompson Creek Metals Company Inc. (TCM), started operations in September of 2013. It is located between the communities of Fort St. James and Mackenzie and is the first major metal mine to open in British Columbia in 15 years. Based on reserves as of January 1, 2014, it has an estimated 22 year mine life with 2.1 billion pounds of copper and 6 million ounces of gold in reserves. Like all commissioning operations, there have been issues achieving design throughput and recovery due to flow sheet design, equipment failures, control philosophy, and reagent scheme. Efforts to improve overall mill performance include equipment modifications, reagent screening and testing, and grind size testing. Applying these changes to the mill and working closely with the mine has resulted in continuous improvement each month as Mount Milligan looks to achieve the nominal design capacity of 60,000 dry metric tonnes per day in the later part of 2015. Considerable focus is being placed into ensuring size reduction equipment is utilized effectively. Additional modifications and tests are being undertaken to steadily improve processes and alleviate restrictions in the mill. This paper will discuss the start-up and present ramp-up history of Mount Milligan, the current mill processes, and the steps taken to achieve expected production numbers.OPERATION BACKGROUNDMount Milligan is an open-pit copper and gold operation wholly owned and operated by Thompson Creek Metals. It is located approximately 155km northwest of Prince George, British Columbia, between the communities of Mackenzie and Fort St. James. The copper-gold porphyry deposit contains a Measured and Indicated Mineral Resource of 706.7 Mt at 0.18% Cu and 0.33 g/t Au, containing 2.84 billion lb. copper and 7.50 million oz. gold. Mine life is currently estimated at 22.1 years (“Feasibility Update – Mt. Milligan,” 2009). The mill is designed to process 60,000 dry metric tonnes per day and produce 400 dry metric tonnes of concentrate per day averaging 25.5% Cu and 40 ppm Au. Concentrate is delivered by truck and trailer to Mackenzie followed by rail to Vancouver for overseas shipping to various customers.Mount Milligan is considered a “zero discharge” operation meaning no process or surface water will be discharged to the environment. As well, stockpiling is very limited and is only permitted for a short period of time. This scenario presents several unique challenges. Scheduling of ore/waste production must be carefully planned as waste rock is used to build the tailings storage facility (TSF). Reagent selection is also important as persistent chemicals will have a tendency to build up in reclaim water which feeds the process water tank."

Jan 1, 2015

For the first time in its history, the George A. Fox Conference let its focus venture away from the friendly confines of the East Coast of the United States to spend part of the one-day conference looking at projects from around the globe. With a record-setting attendance of 377 people, the conference, titled ?Tunneling: An international perspective,? opened with a keynote speech from special guest In-Mo Lee, professor, Korea University in Seoul, South Korea. He is also the president of the ITA-AITES. In a sweeping presentation, Lee walked the packed audience through some of the most fascinating and challenging projects in his home country. Among the projects he spoke about were Korea?s longest railway tunnel, the Solahn Tunnel and the Inje Tunnel, a freeway tunnel that is 11.94 km (7.4 miles) long.

Jan 1, 2012

From the massive equipment that moves the earth, to the parts that keep the equipment moving, it was all on display for more than 35,000 people who at-tended MinExpo 2008 at the Las Vegas Convention Center Sept. 22-24. In the largest show in the illustrious history of MinExpo, the success of the recent commodity boom was reflected in the more than 55,700 hm2 (600,000 sq ft) of floor space that was jam-packed with nearly 1,300 vendors. Among them, the makers of the industry?s largest machines, displaying their latest and greatest trucks, shovels, excavators, drills and other mining equipment. During the nearly decade-long commodities boom, equipment makers have worked hard to keep up with demand while also investing heavily in research and development. The beneficiaries of this R&D is the end user who saw first-hand at MinExpo 2008 the many advances that have already been made in safety, comfort and productivity from all the manufacturers. R&D has also helped spark more talk of automation, which is being used already at some of the world?s largest mines. Caterpillar and Komatsu have worked with the technology in surface mining and Bucyrus and Sandvik are among the industry leaders applying the science of automation to underground mines. Technology has in-creased greatly since the idea of moving massive equipment remotely was first knocked around and the idea of entire fleets operating around the clock seems to be getting closer to reality. But, until that happens, MinExpo attendees were treated to a show that featured some of the most impressive current machines the industry has to offer. In the largest booth space of the convention, Caterpillar (www.cat.com) displayed the culmination of an ambitious $280-million dollar investment, with the introduction of its new mining fleet of four new trucks. The F-series was un-veiled with common features in safety, cabs, engines, frames and bodies and Tier 2 compliant engines. The F series also features a return to the electric drive option. ?When our customers asked us for improvements to our mining trucks, we responded by making a record investment in every single truck in our line, as well as the increased capacity to produce more of them,? said Cater-pillar group president Stu Levenick. ?New technologies have allowed us to make trucks more reliable, easier to maintain and more friendly to the operator and to the environment.? The 793-series is in the 218- to 227-t (240- to 250-st) class that will be available in both mechanical (793F) and electric (793F ac) versions. The electric drive-only 313- t (345-st) 795F was also introduced, while the flagship 797B truck is in the process of being replaced by the new 797F mechanical drive, maintaining its 345- to 363-t (380- to 400-st) target payload. Completing Caterpillar?s new mining truck line will be new versions of the 785 and 789 mechanical drive trucks. The next generation of trucks will be phased into production during the next two years, with the Cat ac drive models expected to go into production in late 2010. The $280-million in-vestment is Caterpillar?s largest commitment ever to the mining industry

Jan 1, 2008

By Conochie D. S, Grave N. C

Disposable-tip emf cells at present used in liquid steel can be used to measure the state of oxidation of high-iron slags produced in non-ferrous smelting. This provides a new tool for the control and evaluation of pyrometallurgical operations.An investigation of oxygen potential variations throughout a typical nickel smelter using the flash smelting technique gave a valuable insight into the process. Correlations of oxygen potential with ferric to ferrous oxide ratio and nickel content in slag were in reasonable accord with equilibrium data in the literature indicating that the probes may be used both as a plant investigation tool and possibly as a means of obtaining thermodynamic data for slags.

Jan 1, 1979

By Ruxton B. P, Rhodes J. M

Two Rb-Sr ages are discernible in data concerning the leucocratic granite which is the youngest pre-sedimentation phase of the crystalline basement complex at Rum Jungle, Northern Territory, Australia. Whole-rockdata suggest that intrusion of this unit took place at about 2400 my ago, with a probable initial ratio around o·707; whole rock-potassium feldspar tie-lines indicate redistribution of strontium at about 1800 my ago. The former age correlates with other measurements on rocks which form basement to the mantling Pine Creek Geosyncline; the latter correlates also with isotopic evidence for regional metamorphism and emplacement of some younger intrusive granites elsewhere within the geosyncline. A few K-Ar ages, from scattered localities, conform generally with the later event or events which appear to have some connection with the structural deformation clearly observable both in the complex and the surrounding metasediments. It is these younger events which appear to match the residual evidence for the earliest detectable concentration of uranium minerals in the Alligator Rivers district.

Jan 1, 1977

In the extraction of level bridge pillars in the South Mine by square-setting methods the general practice is to work transversely from the hanging wall in narrow sections three or four sets wide to the depth of the bridge-usually three sets. When the working block attains an area of twelve square sets, sand filling is run in, either by pneumatic (Proceedings No. 123, 1941) or hydraulic methods, in order to control the settlement of the general area and prevent the development of undue weight in the stope. Upon completion of the filling operations, or coincident with them, ore breaking is resumed and the transverse section of the bridge pillar gradually reduced. A number of these parallel sections may be working at the same time.In preparing a block of sets for filling a great deal of paddocking is required, both to contain the filling and to preserve access to ladderways and ore chutes which may be situated at some horizontal distance. Stope paddocking until recently was constructed of 10 in. x 2 in. boards nailed...

Jan 1, 1942

By M. K. McCarter

Surface mining applies to extraction of mineral resources from water and sediments of rivers, lakes, seas, and oceans; from solutions circulating through broken rock and soil; and from rock and soil excavated from the earth. Surface mining is responsible for the majority of mineral production in the United States and a substantial portion of the world?s total production. This section deals specifically with extraction methods which employ mechanical processes in a relatively dry environment to free minerals from the earth. The following section, Section 15, deals exclusively with aqueous methods. With recognition of the importance of reclamation in all activities which temporarily disturb the earth?s ecosystems, it is appropriate to classify mechanical extraction methods as either deferred reclamation or concurrent reclamation. Deferred reclamation is necessary when the shape and logistics of the excavation require that it remain open throughout the productive life of he project. Upon exhaustion of economic reserves, the opening is then reclaimed in a manner consistent with public safety, environmental acceptability, and land use policy. Methods employing deferred reclamation are commonly referred to as open pit or quarry mining. Metallic ores, industrial minerals, and coal are all extracted using open pit methods. Typical examples are provided in Chapter 14.1.

Jan 1, 2008

By A. R. Barnes, A. F. Newall

Keywords: Pyrometallurgy, furnace, smelting, spinel, PGM, phase diagrams As Merensky reef ores are replaced by UG2 ores, chromium levels in PGM smelting furnace feeds have steadily increased. Increased chromium levels lead to operating problems. Attempts to increase the chromium solubility in the slag by a variety of techniques create other difficulties. The authors have developed a technique for removal of the chromium spinel interface along with the matte for subsequent separation outside the smelting furnace by utilising differential solidification in the ladle. The process has been patented internationally with support from the Innovation Fund.

Jan 1, 2006

By Carl Hendricks, Malcolm Scoble

There currently exists no viable means of obtaining continuous, quantified feedback on blast efficiency. This paper describes the adaptation of a loading shovel to serve as a diagnostic tool in evaluating the success of ground preparation practices. Work undertaken in a large western Canadian open pit involved microprocessor-based instrumentation for the performance monitoring of an electric mining shovel. The monitored shovel responses proved to be reliable indicators of variations in muckpile d&ability. This approach is considered to provide a very comprehensive survey of post blast conditions since the shovel must physically interact which every cubic yard of blast fragmentation.

Jan 1, 1991

By F. X. Prins, L. R. Nelson

Tight control of electrode paste additions, hard and soft paste levels, baked zone position and electrode temperatures are integral to superior Söderberg electrode management practices. Paste addition is typically effected through briquettes, cylinders or large blocks. Each electrode paste form has its advantages and disadvantages, but probably a more crucial element from an electrode control perspective is the frequency and amount of electrode paste addition into a Söderberg electrode column. The detrimental effects of excessive soft paste levels leading to Stokes? Law segregation of paste in the electrode column are well documented, while several operators have effectively implemented the use of electrode thermocouples to monitor paste temperatures and automated slipping algorithms to control baking conditions within electrodes. Somewhat less well appreciated are the negative influences of inadequate soft paste levels, especially when coupled with excessive paste cylinder or block additions and resulting high hard paste levels. The alternative of insufficient hard paste levels and associated overheated electrode paste must also be considered, and can contribute to paste segregation directly. This condition also has the potential to generate gas mixtures in the electrode column that are concurrently a potential health hazard, while being prone to spontaneous combustion. Results of industrial trials on electric furnaces using Söderberg electrodes in a variety of applications from ferrochromium, to ferromanganese and even platinum-bearing base metal sulphides smelting are presented to illustrate the influence of paste loading practices on the dynamics of hard and soft paste levels. Possible electrode failure mechanisms attributable to inadequate paste level control will be discussed through some industrial examples. Suitable paste loading practices to mitigate the risks of inappropriate paste levels and associated electrode incidents are presented.

Jan 1, 2004

By W. Rogers

Blast-induced rock mass displacement can have a significant impact on ore loss & dilution. The mischaracterisation of the grade boundaries both prior to, as well as a result of blasting can lead to significant financial losses on account of ore loss and dilution. Ore dilution occurs when waste material is miscategorised as ore and sent for processing or stockpiling, diluting the run of mine head grade and recovery. Ore loss takes place when valuable mineral is miscategorised as waste and sent to the waste dumps, thus never being processed and recovered. Extensive research has been conducted at the University of Queensland over the last fifteen years to understand the impact of blast movement on ore loss and dilution. Recent outcomes of this research have developed innovative tools and techniques to measure and model blast movement. These techniques have been implemented at Ahafo gold mine in Ghana to understand blast movement dynamics and to implement solutions to reduce blast-induced ore loss and dilution. These solutions are validated through controlled trials and have been incorporated into site standard operating procedures to sustain the benefits.

Jan 1, 2012

By S. Bellec, A. Berton

"Usually, steady state mass balances are used for the design of mineral processing plants. However, this tool does not take into account the impact of process inputs variability nor does it evaluate process transient behaviours between stationary states, such as mill start-up and shutdown. The use of advanced simulations enables the integration of dynamic behaviours in process design decision-making by highlighting situations that are undetectable by using only steady state mass balances. Applying these simulation tools to brown field projects allows the simulator performances to be calibrated and validated on actual plant data before it is used as a prediction tool for the modified plant.Three (3) simulators were implemented at the design stage of a major upgrade project for an ore processing plant in order to assess process behaviours under different production scenarios. These simulators were built to evaluate the impacts on major elements such as mine production, ore stockpile, concentrator production as well as water demand. A validation of individual equipment models was performed whenever sufficient measured data was available. The simulators were then used to study the impact of ore variability (grade, hardness, throughput), to assess day-to-day production special events, and to evaluate the true stockpiles live capacity.The use of a stochastic simulator for equipment sizing allowed a more precise sizing of many pieces of equipment and avoided important expenses in the fresh water pumping system. The dynamic simulator also confirmed that the water in place system would suffice, even in the most demanding production scenario. Finally, the stockpile simulator allowed an important production bottleneck to be quantified and then made possible the assessment of various practical solutions for the stockpiling-reclaiming issues.Post start-up, process data underlines the fact that using advanced simulation tools was useful to mitigate process-related risks associated to the plant expansion, showing generally accurate prediction and adequate equipment sizing, leading to smooth process commissioning. The presented methods are part of what is now routine in Soutex’s participation in both greenfield and brownfield projects."

Jan 1, 2015

By Vincent A. Scovazzo

On March 12, 1994, the 1,100-foot deep 2 Yard South panel of the 1l0 year-old Retsof Mine collapsed. At the time of this occurrence, the Retsof Mine was characterized as the world's largest, most productive salt mine. The collapse produced a seismic event and resulted in a sinkhole and small lake forming on the surface. An existing highway bridge was rendered unusable. Water entered the mine and despite valiant efforts by the miners and the mining company, the entire mine was flooded and lost. John T. Boyd Company (BOYD) studied the incident to evaluate design procedures, and assess the short- and long-term environmental impacts of the collapse. This paper presents our analysis of the cause of the collapse and our review of the rock mechanics design of 2 Yard South panel. Our review is, in part, based on a rock mechanics monitoring program of 2 Yard South. The monitoring program was established by the mining company as the panel was developed and continued even after the panel became unstable.

Jan 1, 1997

By Konstantinos Modis

According to recently established theoretical analysis and under certain conditions, a critical sampling density can be determined for an earth-related space-distributed natural variable. Sampling above this critical limit adds little to the mapping results. The objective of this paper is the application of the above theory to the Sesklo clay quarry in Greece, where Heracles General Cement Company had conducted a sampling campaign to estimate its reserves. The structural analysis of Al2O3 values generated a variogram model, from which the critical sampling density was identified. This critical number was by far lower than the existing sampling density. Clay reserves were then estimated using geostatistics and inverse distance squares in different data schemes with variable densities. The results of the comparisons between the various models revealed that, when the sampling density was greater than its critical value, geostatistics and deterministic interpolation gave similar estimations, which is also in agreement to the theory. The optimal sampling grid finally proposed here, will result to significant cost savings in the next drilling program which is now in plan by the company.

Oct 1, 2009

By Afonso Rangel Garcez de Azevedo

A crescente preocupação com a qualidade da cerâmica vermelha e com o uso racional dos recursos naturais utilizados por ela, tem motivado a diversas pesquisas em busca de uma otimização de seu uso. Atualmente o setor produtivo em geral faz uso de um método empírico para formulação de massa cerâmica, tendo como principal consequência à perda da qualidade de seus produtos, isso e fruto da insuficiência de estudos dos solos em diferentes pontos das jazidas utilizadas. Este trabalho tem como objetivo a caracterização, através de ensaios de granulometria, Limites de Atterberg e analise química para um conhecimento dos solos a serem utilizados na composição da mistura. Com os resultados encontrados pode-se dar algumas diretrizes iniciais para uma melhor adequação na formulação das misturas, diminuindo o empirismo e aumentando a qualidade dos produtos.

Aug 16, 2017

By K. Galos

The paper presents increasing importance of mineral secondary and waste raw materials in the minerals management in Poland. Definition of mineral secondary and waste raw materials is proposed, according to current Polish law. On this basis, sources of various types of mineral waste raw materials are analysed. The special attention is paid to the wastes from mining and processing, wastes from power plants, and wastes from steelworks and other smelters. Other types of waste and secondary materials, such as metallic containers, glass containers, batteries, metallic wastes and scraps, are also taken into account. Analysis of sources of such materials is shown together with the main directions of their economic use. Available sources of information on manufacture and use of the mentioned secondary and waste raw materials are also analysed. Finally, for a wide range of waste materials, their current and expected significance as substitutes for some industrial and construction minerals in Poland is given.

Jan 1, 2011