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By R. A. Kinzie

In a conventional cement plant, the drying and heating of the raw material takes place in the upper section of a cylindrical kiln where the heat exchange is poor. In a Lepol kiln this part of the process is carried out on a traveling grate where the heat exchange is efficient. The increase in fuel economy justifies the greater complexity of the installation.

Jan 1, 1950

By G J. Halstead, R C. Steinhaus

The True Pipe® in-line sampler was developed in an attempt to address the need for a mechanically reliable and correctly designed sampler to suit one-dimensional pressurised slurry pipelines, often found in metallurgical process plants but for which no reliable and representative sampling solution as yet exists.The design, whose operation is based on the principle of symmetry, is described by Dominique François-Bongarçon (2005) with the synchronous opening and closing of relevant valves. It representatively isolates portions of the particulate material stream at predetermined intervals for effective extraction of primary increments for subsequent sample compositing.Theory of Sampling applicable solutions have proven elusive in flowing pressurised particulate material streams, with various attempts to date not having formulated a viable, mechanically reliable and acceptable design.Compliance to sampling theory is critical, and a number of tests were conducted where certain operating parameters were altered to determine their influence and sensitivity on sampling representativeness.The results of the initial series of tests performed on a carefully designed rig are presented, with additional work discussed for necessary investigation in the near future.Getting closer to a robust, economic and correct design for this challenging application in the minerals industry may now not be that far away. Plant management staff will see improved metallurgical mineral balances around their process plants and significantly reduced sampling discrepancies, particularly in tailings applications. Improved quality control is now possible where, due to plant head room constraints, classical cross stream sampling methods cannot be employed.CITATION:Steinhaus, R C and Halstead, G J, 2014. True pipe sampler – a correct design utilising the principle of symmetry in pressurised slurry particulate streams, in Proceedings Sampling 2014 , pp 127–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

"Far from being eclipsed by petroleum and natural gas, Canadian coal continues to command wide (and apparently growing) interest.Major R & D investigations are currently heavily oriented toward coal beneficiation (e.g., cleaning and utilization of fines) and toward a broad range of studies on metallurgical coals and cokes. However, active work is also being carried out in the areas of coal geology, mining, transportation and combustion; and, in some laboratories, increasing stress has been laid on developing a number of new, essentially non-fuel uses for coal and coal products.This review summarizes the work of Canadian coal research agencies during 1966 and indicates some of the more important advances made by them."

Jan 1, 1967

By S. Philipp

This paper describes several variants of placement and design, from a technical and economic point of view, of shafts, ore bunkers and drifts near shafts of a Russian potash mine. Advantages and disadvantages of the position of different workings are shown as well as an analysis of stratigraphic and geological layers and their use for excavating pit bottoms, haulage drifts and bunker installations. The potash mine consists of two hoisting shafts and one service shaft. The hoisting capacity of one of these skip shafts is planned to be approx. 7 Million tons of crude potash salt per year. Both shafts together will have a hoisting volume of about 14 Million tons. When the mine will increase their highest level of production, it will be one of the biggest potash mines in the world. The skips, the hoist drives and the bunker near the shaft will belong to the largest ones worldwide, too. This paper specifies the features of such a double skip shaft pit in detail and demonstrates problems, which depend on the fact that the pit bottom is in a depth of nearly 1200 m.

Feb 23, 2014

By D. E. Redmon

The Federal Bureau of Mines has studied the locations and general features of 90 pegmatites found in north-central New Mexico. The dominant valuable product of the pegmatites is muscovite, both sheet and scrap. However, the Harding pegmatite in Taos County is mined only for beryl. Many attempts have been made to recover scrap mica on a large scale by mechanical beneficiation of pegmatite, but the operations heretofore have been short-lived. The Globe mine and the Apache mine, both near Petaca in Rio Arriba County, have been the most important sources of sheet mica in New Mexico. Recognition of the growing need for some of the minerals derived from pegmatites led the Bureau of Mines to investigate the occurrences of pegmatite.

Jan 1, 1961

By M. Li, T. H. Dubaniewicz, H. N. Dougherty

"INTRODUCTION Underground mines have the risk of accumulation of gases if not ventilated properly or during and after emergency situations when ventilation controls become damaged or stop working. Common gases that are monitored in underground coal are carbon monoxide (CO), oxygen (O2), and methane (CH4). Methane is a gas found in coal and released through mining; its explosive range is between 5% and 15%. Methane is commonly monitored on all mining equipment and with handheld gas sensors carried by most underground coal miners. Fiber optics (FO) is a popular technology applied in underground mining, particularly for its electric isolation. Many miners are familiar with FO cables hung throughout the mine, which are primarily used in the communication of voice and data (Taylor et al. 2010). Advancements in laser and fiber optics have made this technology well suited for gas sensing the harsh environment of mining applications. The work of the U.S. Bureau of Mines on the use of fiber optic monitoring of gases in mines started in 1992. Dubaniewicz et al. (1992, 1993, 1995, 1999, 2003) developed prototype gas sensors, including methane gas sensors, for research purposes. Previous research (Dubaniewicz & Chilton 1992) identified potential fiber optic gas detection cross-sensitivities associated with the index of refraction of various gases. Index of refraction effects was noted for carbon dioxide (CO2), which is produced in significant quantities by mine fires or explosions. NIOSH released a broad agency announcement (BAA) for the development and demonstration of mine safety and health technology (CDC NIOSH 2017). The objective of this announcement was to validate a sensor, specifically fiber optic, for the mine environment and test it in an actual working mine. The RSL FO sensor “OptoSniff” provided from this work is capable of hundreds of sensing points over distances of up to 20 km, has a measurement range of 0.05% to 100%, senses in an oxygen- deficient environment, and has no gas cross-sensitivity (RSL, 2014). The RSL system is totally electrically passive outside the central control unit (CCU), which can be housed in an MSHA-approved explosion-proof (XP) enclosure or in a control room outside of the permissive area. The sensor was tested in dusty and signal loss situations, showing it is tolerant of dust, has functioned at signal losses up to 90%, and was successfully tested in a mine environment for a five-month period (Walsh et al. 2014). This paper describes how the RSL FO sensor is used for testing using smoke and its contaminants for applicability in emergency situations. The testing investigates individual contaminants such as CO2, temperature, and smoke. Each test was performed separately and methane concentration, laser power, and response time data were collected."

Jan 1, 2019

By Glen Smith

Nautilus Minerals, the world?s leader in exploration and development of deep ocean seafloor resources, is today focused on the recovery of high-grade copper and gold in seafloor massive-sulphide mineralization. These targeted mineralized belts, analogous to land-based volcanogenic massive sulphide deposits, are located near plate boundaries in the back arc basins of the Western Pacific. The first deposit to be developed by the company is located at a depth of 1,600 meters at Solwara 1, in the benign waters of the Bismarck Sea. This location lies within the territorial waters of Papua New Guinea. From 2006 to 2009 the company completed detailed environmental and geological studies at Solwara 1, culminating in a number of world firsts, including the first Environmental Permit granted for the extraction of seafloor massive sulphide deposits and the first NI 43-101 compliant seafloor massive sulphide deposit resource statement. Nautilus has relied heavily on proven deepwater technologies from the oil and gas industry in the design of its production system. Pipeline trenching units, workclass ROVs, deepwater production risers and drill cuttings removal systems will be adapted to initiate this new and exciting industry. Key contractors used by Nautilus on this innovative project have all been selected for their deepwater experience (gained in the oil and gas industry), creativity and determination to launch this new industry successfully. Innovation is at the forefront of Nautilus? success to date. This paper summarizes the progress to date of this development which will provide a new source of minerals for the world and which will contribute to sustainable growth for the future.

Jan 1, 2010

By A. M. Whiting

Competition for coal producers and their primary customers has constantly increased during recent years. The effects of the Clean Air Act Amendments of 1990 on the electric utility industry, coupled with the normal complexities of coal production, quality control, transportation and contracting techniques have spurred both buyers and sellers to increase their level of sophistication. This paper will review the basic aspects of the U.S. coal business and explore the commercial approaches which have proven to be most successful.

Jan 1, 1994

By W. G. Pariseau

"The Crandall Canyon Mine (CCM) is located in the Wasatch coal field in central Utah. Extensive longwall mining at CCM preceded a decision to recover coal left in barrier pillars on each side of a set of main entries extending far into the mine. During mining in March 2007, a major bump occurred that led to cessation of mining in the barrier pillar on the north side of the mains and to the start of mining in the south barrier pillar. Subsequent loss of ground control in August 2007, through coal pillar bursts had tragic consequences with loss of six miners and shortly afterward three rescue team members. A U.S. Mine Safety and Health Administration (MSHA)report describes the events in detail (MSHA, 2008).An important lesson to be learned from CCM is the need to select a computer program suitable for pillar design. Computer programs are engineering tools and selecting the right tool for the job is essential. In this regard, minimum program requirements include capability for computing stress distribution within a pillar and adjacent roof and floor strata. The reason is simple: strength of rock is stress dependent; both vary from point to point in pillars and adjacent strata. Preferably, one should follow the evolution of stress as the mining plan is executed from start to finish to assure safety or to warn of a potentially hazardous situation developing as mining progresses.The approach to the problem posed by barrier pillar mining at CCM is conventional in the sense of applying well known finite element modeling techniques to analysis of a proposed mining plan. The engineering purpose is to evaluate the mining plan with respect to ground control questions including roof, floor and pillar safety. Results of previous two-dimensional finite element analysis indicated pillar safety was by no means assured (MSHA, 2008; Pariseau, 2008; Pariseau, 2011). Geometry of barrier pillar mining is limited in two dimensions for example, crosscuts are not seen in vertical cross sections. While three-dimensional analyses are preferred, even moderately sized regions often lead to very large problem sizes that exceed computer capabilities. However, a recent development in finite element modeling of tabular deposits allows for whole mine analysis in three dimensions. This technique involves a dual node - dual mesh concept. Both have been used separately in much earlier work, but are only now used in combination. It is possible to have an estimation of subsidence at a kilometer scale and details of stress, strain and displacement about barrier pillars, main entries and pillars, and so on at a meter scale (Pariseau, 2014). No compromise involving empirical formulas or similar guess work is required. Indeed, all calculations are based on first principles: physical laws, kinematics, and material laws. Effects of joints and in situ variability or uncertainty in strata properties, elastic moduli and strengths, may be included for greater realism. An important objective of the present study is to assess the role of three-dimensional pillar geometry in arriving at conclusions regarding barrier pillar mining versus two-dimensional results."

Jan 1, 2014

By N Setoudeh, A Nosrati, N J. Welham

The current surge of interest in lithium (Li) is due to the anticipated demand for electric vehicles and small scale power storage. Brine deposits contain most of the global Li resource, however hard rock deposits can be more readily and rapidly developed and comprise the majority of proposed projects. These projects plan to use the conventional processing routes of dense medium separation and / or flotation to produce a spodumene concentrate for sale. The standard route for subsequent processing of spodumene concentrate is thermal decrepitation, acid leaching, solution purification and precipitation of lithium carbonate. This is typically followed by further purification. A number of projects have ores which contain other lithium minerals, principally micas, lepidolite and zinnwaldite, necessitating an alternative treatment route. Several different routes for spodumene processing are under development to reduce costs to compete with brine projects. This paper will give an overview of the strengths and weaknesses of the current and alternative processes.CITATION:Welham, N J, Nosrati, A and Setoudeh, N, 2017. Lithium ore processing – an overview of the current and new processes, in Proceedings MetPlant 2017, pp 185–194 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By J. F. Barkley

Smoke abatement is a subject of which fuel technology, although absolutely essential, is only a part. Its successful accomplishment starts and ends with human factors that must be given thorough consideration; between this "start" and "end" fuel technology is applied. Smoke abatement usually starts from the desire of some person or persons to be free from uncleanness caused by the stack of someone else and ends with the sincere desire of the operator of the fuel-burning equipment to maintain a clear stack. Although "smoke abatement been discussed for many years, it is only recently that the public has been mindful of such expressions as "air pollution" and "air hygiene." The subject has duel in common with that of supplying pure water but is more complicated. The public desires pure water, expects pure water, is willing to pay for pure water, and expects to continue to pay for it indefinitely; it is a development of civilization. It is doubtless correct to say, however, that people in general do not et realize the detriment of air pollution to their well-being or give the question enough serious consideration. This is illustrated by the fact that in city smoke abatement it is the mass of small householders that sins the most and is the hardest to handle. It is rather difficult to assemble a group of people in a room without the air becoming contaminated with smoke. Smoke abatement will lag with the lack of desire for pure air - probably the biggest human factor involved in its accomplishment.

Jan 1, 1939

By Xinyang Wang

It is believed that sulfur and volatile matter contents in coals are the main intrinsic properties to cause the self-heating of coal. Their oxidation at lower temperatures than that of fixed carbon to initiate coal's self-heating should be quantified. This study is aimed to improve the previous mathematical model developed by the authors for studying the coal's propensity for spontaneous combustion. It enhances the model's ability to consider the effects of sulfur, volatile matter and moisture contents in the coal - three important factors affecting the coal's self-heating process. Sulfur exists in coal primarily in the form of pyrite which will be oxidized rapidly under suitable conditions. Volatile matters, higher in low rank coals, are more easily to be oxidized. Heat of water condensation provides initial energy for low temperature oxidation. Heat release rates for pyrite oxidation and moisture condensation are built in the model. Finally, the simulation results in terms of time versus temperature on pyrite oxidation and moisture condensation are validated with the adiabatic testing data respectively.

Jan 1, 2013

By R. F. Abernethy

Recent investigations in the United States and in other countries have produced considerable information on the nature and occurrence of minor elements in coal. The possibility of recovering certain elements, particularly germanium and uranium, from coal ash and other coal products has received considerable attention. Some flue dusts are potential sources of germanium, and certain lignite deposits are potential sources of uranium, but industrial recovery of these elements has been limited to small quantities for technical and economic reasons. Considering the large amount of coal mined annually, a small percentage of a rare element may have industrial significance if an economical method of recovery can be developed. In 1944 information on the occurrence of rare elements in coal was reviewed in Bureau of Mines Technical Paper 669 (46).3 This report is a revision of that paper with the view of summarizing published information available for United States coals, and pertinent information concerning coals of other countries. Selected references from the original paper are retained. New references do not include all preliminary reports when more permanent literature describing complete projects is available. Consequently, the list of references should not be considered complete.

Jan 1, 1963

By Xing Jin, Dan Graffi, Glenn MacPherson, Dan Rioux

"The complexity of a modern flotation circuit makes it susceptible to disturbances such as changes in feed, ore mineralogy, equipment degradation, poor measurements and faulty instruments. Good measurements and a robust control system are critical to create and maintain a stable and optimum flotation process.This paper focuses on the development and implementation of process control applications in the flotation circuits at Xstrata Nickel’s Strathcona Mill ( referred to as the mill hereafter ) in Sudbury, Ontario. Following the path of ‘stabilize-improve-optimize’, basic controls to stabilize process variables such as flotation cell pulp level, air and reagent addition rates, cleaning-column feed and wash-water rates have been established. Factors such as best practice in pulp level and valve position measurement, feedforward control and the application of an appropriate control philosophy, have contributed to the significant reduction in process variability. For instance, standard deviation reduction of 79% for the Ni impurity in the column Cu concentrate grade was experienced and is shown. The variability reduction of the flotation circuits’ key process-variables paves the way to further improve and optimize flotation performance. A grams-per-metal unit reagent addition control scheme has been improved upon, particularly for different operating scenarios and better robustness. In addition, following significant stabilization of the primary controls and columns feedrates, Cu/Ni separation cleaning-column bias-control (cascaded to the wash-water rate) and hold-up control (cascaded to air flowrate) have been developed and tested. This strategy – from stabilization to optimization - is expected to achieve a more consistent control of final concentrate grades and improve recoveries.INTRODUCTIONFlotation is considered the most important and value-added process in the milling metallurgical plant and is still undergoing continuous evolution to treat greater tonnage and different ores (Wills, 2006). Starting over three decades ago, with the advent of on-line slurry content analysis devices, flotation automatic control has received persistent interest and a large number of applications have been reported (Thwaites, 1983, 1986 ; Mckee, 1991). Bergh and Yianatos (2011) reviewed different aspects of process control in flotation circuits and have evaluated the applicability of model predictive control to the process. Mckee (1991) analyzed the difficulty in developing lasting/robust process control applications for flotation circuits and stated that the path of stabilization-refinement-optimization would more likely lead to successful flotation circuit process control. Best practice on column process control was discussed by Bouchard, etc. where a multi-layered approach was proposed, provided that the measurement of column process variables ( i.e. bias, froth depth, hold-up, etc. ) are measured reliably (Bouchard & Thwaites, 2008). Wills (2006) stated that the best practice for flotation automatic control starts with fulfilling basic control objectives, such as stabilized flotation cell level, air flow, pH, reagent flow etc., before considering more advanced, or even optimal, control of metallurgical targets, which are more closely linked to economic performance."

Jan 1, 2013

By William C. Howe

This paper describes the technical status of the atmospheric pressure fluidized bed combustion (AFBC) process for utility steam generation. Major areas where AFBC development work is needed are discussed. Various approaches to solving these key issues are identified and the ongoing research and development programs addressing the key development areas are described. Other significant programs pertaining to the development of AFBC for utility steam generation are also discussed and needs for future work identified.

Jan 1, 1978

By M. J. Ferrante

Relative enthalpies of high-purity disodium hexatitanate (Na2Ti6013) were measured at the Bureau of Mines to provide new thermodynamic data needed to advance the technology of materials. Measurements from 298.15 to 1,478 K were made by drop calorimetry with a copper block. Tabulated values are listed for the standard relative enthalpy, heat capacity, en-tropy, and Gibbs energy function between 298.15 and 1,500 K. Enthalpy data are also given in equation form and are combined with thermodynamic data from the literature to derive values of standard enthalpies of formation, Gibbs energies of formation, and logarithms of the equilibrium constants of formation. Similar calculations were made for the reaction of Na20 with Ti02.

Jan 1, 1986

By S Shafiee, N Abbate

The evaluation of mining projects requires a methodology that will give flexibility and manage the existing uncertainty within the projects. The discount cash flow (DCF) and other traditional evaluation approaches, which are widely used in evaluating a significant number of mining projects, have simply assumed that the main variables remain constant in their evaluation; elements such as discounted rate, mine life, operating cost and production rate. The DCF ignores managementÆs flexibility to adapt and reforecast and revise decisions. Real options valuation (ROV) is one of the modern evaluation methodologies that provide a tool to adapt and revise mining projects under uncertainty and future variables movements. ROV brings more variables into the evaluation model compared to DCF and assumes them as uncertain and dependent. Finally, ROV provides a range of solutions that can assist in managing this flexibility.This paper endeavours to compare ROV and DCF for mining projects comprehensively and applies these two techniques in the model. The paper shows that ROV will be inclusive of extra value in mining projects due to variables not allowed for, or even ignored, when the DCF model alone is used. One of the significant advantages of the ROV method is being able to evaluate mining projects under different scenarios from the inception of the projects. Furthermore, ROV gives the ability to evaluate the mining project while allowing for abandonment, temporary suspension, or expanding the mining project. In other words, the ROV evaluation process creates an analytical environment, which allows for optimisation of the mining plan within the mining project, as well as the ability to change the capital structure dependant on existing circumstances over the life of the project. The ROV is a new evaluation method that can add value in mining project analysis and offers opportunities to amplify gains, or to mitigate losses. This paper also discusses some of the reluctance to use ROV instead of DCF in current project evaluation.CITATION:Shafiee, S and Abbate, N, 2012. Now, this is the time for mining companies to choose - Real option valuation or discount cash flow, in Proceedings Project Evaluation 2012 , pp 225-234 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By Richard Jr. Ray, David Johnston, Phil Blankenship

Injection of inert gases to combat mine fires has been practiced in various parts of the world for a long time. Of late, nitrogen has become the preferred inert gas for control of mine fires and safe salvage of longwall equipment as compared to carbon dioxide or fuel gases produced from burning of fuel. In India, carbon dioxide has been used for fire fighting in a number of mines during the 1960s and 1970s. More recently inert gas produced from burning of fuel oil in surface plants has been used in controlling the atmosphere in fire areas in two mines. In yet other cases, liquid nitrogen has either been poured directly into fire areas in liquid form or injected in gaseous form to keep the fire in check. Nitrogen produced in liquid form in an oxygen plant is more costly than nitrogen produced from PSA (pressure swing adsorption) based plants. A PSA-based plant has been installed in one of the Indian mines in 1986 and more are in the offing. This paper reviews the application of various inert gases in Indian mines and discusses the likely trend of inert gas application in Indian mines in the future.

Jan 1, 1989

By A. Lebedev

Application of dynamic simulation for a base metal processing plant is discussed. The plant receives ore of variable quality from two pits and blending had to be applied to maximise recovery. The plant employs multiple stage crushing, screening, dense media separation, two-stage milling, flotation and further filtration. Stockpiles and bunkers are used in the plant to cater for breakdowns and operating delays, the latter being appropriately incorporated in the model. A detail dynamic simulation model was constructed from the rock face to the filtration plant to assist the plant design, notably with definition of the ore blending method, sizing storage capacity and in-plant conveyors. The plant model was broken down to capital equipment items and various feed types and mass balances were tested to ensure that the production target is met. The dynamic simulation tested the proposed blending method, identified bottlenecks, produced risk profiles for all strategic storage facilities and overall helped minimise the project risks and improve confidence in the plant design. Keywords: Dynamic simulation, ore grade, blending, capacity, risk profile, throughput, utilisation

Jan 1, 2020

By David M. Lake

Conversion to trolley assist is a means of minimizing diesel fuel consumption, which in many mining situations offers a rapid payback of capital investment plus the inherent flexibility and maneuverability of truck shovel operation. When diesel electric truck shovel mining operation with trolley assist is compared to alternative mining methods such as conveyor systems, the trolley assist system can be easily justified in terms of return on investment, payback and increased productivity. A review of present technology, performance requirements and past experience in the mining industry has led to the development of a trolley assist system for diesel electric haulage trucks which, is proven in the mining environment, offers significant reduction in fuel consumption and increased productivity.

Jan 1, 1981