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By T. W. White

One of the objectives of today's mine superintendent is to increase his equipment availability. To this end we have seen improved scheduling procedures, preventive maintenance programs and extensive drive training and operating procedures. However, until recently, one area that has changed little in the past twenty years is the method of refueling and servicing mine equipment. In looking at mines across the country continually one encounters the hazardous oil soaked ground, the hand held fuel nozzle and the maze of hoses of the "traditional" fuel stop. By adapting technology developed in the construction and aircraft industry, current fueling and servicing practices can be easily improved. The result will be less nonproductive time, less downtime from engine failures and increased security from major refueling fires. The time saved almost amounts to having another truck in the fleet! One feature of the improved servicing practice is the implementation of high flow fueling. For trucks now on the market, a flow rate between 120 and 150 gam is feasible, about 90 gam greater than current practice. This flow rate could be increased even further as larger trucks come into use. A second idea borrowed from the aircraft industry is the use of positive lock type connection nozzles that automatically shut off when flow stops. These may be used for fuel, water, oil and hydraulic systems to eliminate spillage and assure that clean fuel, oils, and water are delivered to the vehicles. The reduction of fuel spillage lessens the threat of major fires resulting: in equipment damage and loss. Eliminating fire hazards will become even more important as the turbine engine with its lighter, more volatile fuels come into common use.

Jan 1, 1972

By Y Pan

The recycling of steel is a crucial aspect of the shift toward a sustainable metals industry. The emphasis on steel recycling through the introduction of the scrap based mini-mill concept is also matched with a desire for greater product quality and reduced environmental impact, which, in turn, has generated important innovations. There have been significant advances in the technology for recycling steel over the last 20 years and this paper will provide an overview of these developments and discuss future directions in steel recycling including scrap management, control of tramp elements, electric arc furnace technology and ladle metallurgy.

Jan 1, 2004

By Michel Carreau

Presentation topic Introduction to Renewable Power in Remote Mining Industry Trend What are the Challenges and How to address them Acceptability (Management Buy-in) ? RP not core business to mining company Significant upfront costs Project Risks - Technological and Delivery Wind and solar power variability Operating hybrid power (Operator Buy-in) Conclusion Introduction ? RP at Remote Mining Sites Mining Project Cost Energy represents 25% of mining project CAPEX Energy represents 25% of OPEX Diesel, HFO, ? cost : 30+ cents/kWh RP - Proven technology - Excellent track record ?Wind (20 years), Solar PV (10+ years)? Hundreds of GW installed ?Reliable, High availability, very small OPEX. ?Wind/Solar cost : 15 to 22 cents/kWh (with good resource) ?Potential 10% to 20% Reduction in net cost of energy ?Price certainty for 20 to 25 years

May 1, 2013

By G. Schriever, H. Thiel, E. J. Foell

A long-term, large-scale, disturbance-recolonization experiment with relevance to the environmental effects of deep seabed mining is described. The study is funded by the German government and was launched in the abyssal eastern tropical South Pacific Ocean in February-March, 1989. After obtaining pre-impact baseline environmental data, a 10.8 km2 (4.2 sq miles) circular area of seafloor was disturbed using a specially designed "plow-harrow" device. An initial post-impact sampling series was carried out immediately after disturbance followed by a second post-impact sampling series six months after the disturbance. Plans call for repeated visits to the site at two year intervals to monitor the anticipated slow recolonization process until the area is inhabited by a new, stabilized community.

Jan 1, 1993

By Kefton Teague

The minerals discussed in this section have experienced a gradual, although not spectacular, growth in general. Obvious exceptions are the gradual decreasing use of talc and bentonite as filler materials, partly because of availability and relatively lower sales price of competitive materials. Mineral fillers and filter minerals are used principally in those countries that are heavily industrialized. Except for diatomaceous earth of filter grade, most industrialized countries are reasonably self-sufficient in the various filler and filter minerals. Prices of the various mineral commodities during the period 1950-1970 increased approximately as follows: barite, 43%; diatomaceous earth (filler), 49%; diatomaceous earth (filter), 55%; fuller's earth, 55%; talc. 77%; and bentonite, 94%. Actual usage of these mineral commodities as fillers and filters, during this period, showed changes approximately as follows: (1) Decrease-fuller's earth, 6%; talc, 15%; and bentonite, 29%. (2) Increase-barite, 113%; diatomaceous earth (filler), 150%; and diatomaceous earth (filter), -194%. A relationship between the amount of the various fillers and filters used and price increases is apparent. For example, barite increased only 43% in price, but its use as a filler has increased by 113%. On the other hand, talc, which increased 77% in price, decreased in filler use by 15%; and bentonite, which increased 94% in price, has decreased for filler and filter purposes by 29%. The actual decrease in the use of some of these commodities is not entirely caused by an increase in price. Competitive materials frequently have made substantial gains in the various filler and filter markets. For example, much of the bentonite used in the late 1940s and early 1950s for clarification of mineral and vegetable oils has been replaced by competitive materials. BARITE Occurrences and Sources In the United States, barite is produced from about 14 states, listed in approximate order of importance as follows: Missouri, Arkansas, Nevada, Georgia, Alaska, Tennessee, Kentucky, California, New Mexico, North Carolina, Washington, Idaho, South Carolina, Texas, and others. During the 20 years ending in 1970, almost equal amounts of barite were produced from Arkansas and Missouri. Within recent years, Nevada has replaced Georgia as the third leading barite--producing state. West Germany is second to the United States in barite production. Other important barite-producing countries include: Mexico, USSR, Italy, Greece, Canada, and Ireland. Ireland has become an important barite producer only recently. Barite is obtained from vein and cavity fill-

Jan 1, 1976

By M. S. Moats, W. C. Hartzell

The stable domestic supply of gallium, indium, and germanium has been identified as a critical need for the United States. Electric arc furnace dusts, processed to recover zinc, produce a residue that could be a potential source of these critical materials. An industrial zinc leach residue was characterized to determine its particle size, chemical composition, and predominant mineral phases. Heated, atmospheric, agitated leaching using sulfuric acid and hydrochloric acid was examined to determine the extractions of gallium, indium, and germanium as a function of concentration and temperature. Extractions of gallium were found to be similar to iron in all experiments. The maximum percentage of Ga, Ge, and In leached into solution were 71%, 63%, and 48%, respectively.

Feb 1, 2023

This United States Bureau of Mines study is based on a review of U.S. mine fire accidents that occurred from 1970 through 1989. Information on these accidents was obtained through investigative reports written by Mine Safety and Health Administration personnel. For this study, 260 mine fire accident reports were examined. A previous Bureau research effort established that fires causing fatalities were more likely to occur in haulage entries than at any other underground location. This study has found that the most prolific source of haulage entry fires was the inadvertent grounding of trolley wires. The largest segment (15 out of 40 trolley wire fires) resulted from not maintaining adequate clearance between the trolley wire and the vehicle. Several novel fire prevention and control ideas have evolved in response to frequently occurring fire-related problems. These included; discriminating power isolation devices, wire cutting devices, more accessible fire extinguishers, vehicle overcurrent protection, and vehicle fire suppression.

Jan 1, 1994

By K. Bunney, R. Pleysier

The deportment of a suite of elements through representative gold ore processing unit operations in cyanidation has been investigated. Chromium and lead are not soluble in alkaline cyanide solutions. Arsenic, antimony, cobalt, molybdenum, selenium, tellurium and vanadium are soluble, but typically do not adsorb onto activated carbon to any appreciable extent. Silver, copper, cadmium, mercury, nickel and zinc to varying extents report along with the gold to the carbon eluate. Cadmium, mercury and zinc can report to the carbon regeneration kiln off-gases. Strontium is soluble and adsorbs on carbon where it remgins.

Jan 1, 2011

By B. Boryczko, J. Norwisz, Jose Escobedo Bocardo, Z. Kolenda, A. Holda

"Classical thermodynamic analysis of any thermal and chemical process is usually based on the first law of thermodynamics. Such an approach is not sufficient when deeper understanding of the nature of each elementary process is required. The use of the first and second law of thermodynamics together is necessary to solve practical process more effectively. Enthalpy and exergy balances allow to enhance our understanding of thermal processes especially when cumulative consumption of energy and exergy is calculated. To ensure reliability of such an analysis the least squares method for adjustment of mass balances of principal chemical elements has been applied and described in detail. Numerical analysis has been carried out to compare two different processes of copper production – shaft furnace and flash smelting.IntroductionClassical thermodynamic analysis of any technological process is usually based on the First Law of Thermodynamics in the form of energy (enthalpy) balances. Such an approach is useful in engineering practice as it makes analysis easier in the global scale neglecting modeling of the elementary processes, allows calculation of the thermal efficiency and makes possible to control quality of the measurement results. Additionally, graphical presentation of the energy balance is simple in the form of Sankey diagram.In the case of aluminum electrolysis process, design of the new electrolyzer or its modernization is always based on the enthalpy balance.However, deeper thermodynamic analysis leads to the conclusion that such an approach is not sufficient. The First Law of Thermodynamics guarantees the exact equivalence of the various forms of energy (allowing all forms to be measured in the common unit such as joules) but it does not guarantee interconversibility. Thermal energy (heat) is in a peculiar and unique position, for whereas all other forms can be completely converted into thermal energy, the reverse process id impossible, only a portion of the heat can be converted into mechanical energy. Explanation comes from application of exergy balances. As we know exergy expresses the amount of mechanical work necessary to produce a material in its specified state from components common in the natural environment, in a reversible way, heat being exchanged only with environment [1]. Consumption of exergy connected with the fabrication of some considered product appears not only in the plant manufacturing the product, but also in all plants delivering raw materials for the final production process"

Jan 1, 2008

By Arthur F. Wendt

The following experiments and researches were originally conducted by Dr. Heinrich Rcessler, chief of the German Gold and Silver Parting Establishment at Frankfort-on-the-Main, for the sole purpose of abating the nuisance created by the discharge into the air of the sulphurous and sulphuric acids generated in the process of parting bullion by sulphuric acid. The results achieved have, however, an important bearing not only on this process, but are of value in the manufacture of sulphuric acid and sulphate of copper from sulphurous gases derived from any source. It has now been in successful operation for a term of years at Dr. Roessler's own works, and has been lately introduced with satisfactory results at the royal mints of Kremnitz and Munich, and the well-known establishment of Johnson Mathey & Co., of London.

Jan 1, 1884

By Norman Paley, Finn Ouchterlony

Detailed fragmentation data for different blast delay timing tests at the Red Dog mine in Alaska are analyzed. This work is a continuation of previous work in which the crusher output was found to be better described by the three-parameter Swebrec function than by the Rosin-Rammler function. For a crusher model, the x50 variable sufficed to describe changing crusher input while b and xmax could be considered fixed. For the crusher output from aggregated stockpile rock, as measured by digital image analysis using Split-Online, the constancy of b was not as apparent. In this paper detailed stockpile data, single Split data series, and sieved belt cuts of crusher product are analyzed using the Swebrec and truncated Rosin-Rammler functions. The variability of b is confirmed. By using specific fraction passing sizes a shortcut is presented that removes the need to do curve fitting to determine the three Swebrec function parameters.

Jan 1, 2013

By G. K. Palshikar

Mining operations offer many opportunities for the use of IT and communication technologies to improve automation and thereby deliver higher levels of productivity, cost, quality and safety. In this paper, we discuss a particular application, namely, building a fully automated train control and operation system within a mining area. We first outline the basic architecture and functionality of such a system and then present a real-life case study where the railway system within a remote iron ore mine in Canada was converted to a fully automated train operation system. This hard real-time safety-critical system required the use of advanced technologies such as embedded systems (e.g., on-board train controller), radio communications, formal methods, optimal scheduling, and extensive simulations. We focus on the design aspects for maintaining the system in safe states.

Sep 1, 2012

By P. Dhar, H. R. Kota, M. Thornhill

A very high-grade calcite deposit located in northern Norway consists of CaCO3 ore with minor silicate and sulphide impurities. Cationic (Tallow-1,3-diaminopropane, Duomeen T) collector has been used in the purification of calcite by flotation with an aim of achieving calcite concentrate for its use in value-added products in a variety of industries. The feasibility of sulphide flotation from calcite by this cationic collector has been initially judged from Hallimond flotation and zeta potential on pure mineral systems and the results illustrate the removal of sulphide from calcite ore at neutral pH region. The adsorption mechanism of diamine on both the sulphide minerals was found to be the same by zeta potential studies. The variations in zeta potential are in good agreement with the adsorption of diamine molecular and ionic species as a function of pH. FTIR studies also showed the adsorption of diamine species in agreement with the zeta potential and Hallimond flotation results. Furthermore, the removal of sulphide impurities with selective flotation by diamine collector was performed in bench-scale flotation with the calcite ore and the results indeed showed that the calcite concentrate could meet the quality requirements for its use in the paper industry for coating and filler purposes.

By A Minchinton

With blasting, all far-field phenomena including, but not limited to, stress wave propagation, fracture, vibration and muck pile formation are intrinsically and irrevocably dependent upon near-field phenomena or mechanisms that we describe using physics-based mathematics typically transcribed into computer codes. The energetics involved in such near- to far-field transitions are not fundamentally relevant as they are simply progenitors of these processes.The notion of explosive energy as a descriptor for explosive or blasting performance is a case in point. These energies, which are generally used in blasting tables, are almost exclusively based on ideal detonation theory alone and do not include the influence of the rock, charge diameter, blasthole length and the late-time dynamic expansion that can be predicted using codes based on non-ideal detonation theory.With decoupled charges in presplits for example, the pressure drop between the charge and the blasthole wall can be simply described to first order using the energy relationship associated with adiabatic expansion. However, a more realistic mechanistic solution involves interacting fluids and turbulence leading to dynamic processes such as the channel effect.CITATION:Minchinton, A, 2015. On the influence of fundamental detonics on blasting practice, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 41–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By J. Yianatos

The regrinding stage is necessary to achieve the particle size (liberation) for the final upgrade in the cleaning flotation process. At present, vertical mills (Vertimill) are employed at industrial scale, using small steel balls as grinding media. The regrinding process characterization requires mixing regime knowledge along with the mean residence time of the liquid and solid phases. The residence time distribution (RTD) and the actual mean residence time estimations from theoretical relationships are complex due to the presence of three components (solid mineral, balls and water), mass transport characteristics and segregation affecting solid holdup. Therefore, the experimental RTD determination is suitable for industrial mills. In this work, RTD measurements were performed in two different industrial flotation plants. Both plants operate with Vertimills of 1000-1500 HP in the regrinding process with different circuit arrangements according to the plant treatment capacity. The RTD was measured using the radioactive tracer technique. This technique allows for non-invasive tracer detection where the procedure consists of selecting a liquid (Br82 in aqueous solution) or solid (irradiated solid) tracer for RTD data acquisition in real time. The RTD was modelled by the Large and Small Tanks in Series (LSTS) model, which allowed the characterization of the different mixing regimes for both liquid and solids in the regrinding mills. Effective mean residence times in the range 2-11 min were obtained with RTD shapes similar to those obtained in tumbling ball mills. It was found that residence times of liquid and fine particles were similar, which is consistent with results observed in other mixing systems, e.g. mechanical flotation cells. Also, the mean residence times estimated from the RTD allowed the mass balance adjustment to be validated from metallurgical sampling data. RTD estimations are useful for better understanding the Vertimill behaviour and to identify the actual breakage rates. Keywords: vertical mill, residence time distribution, particle size, modeling

Sep 1, 2012

By Uday Kumar

This paper presents details of an availability study for a fleet of diesel engine operated load-haul-dump (LHD) machines used in a Swedish mine. For the purpose of this study, the LHD machines have been considered as a system comprised of many subsystems like engine, brake, transmission, etc., in series. As availability is dependent on both the reliability and maintainability characteristics of the system, together with reliability, the concepts of maintainability are also discussed. The need for exploring the data for the presence of any structure, which is very common in repairable system data sets, is emphasized with suitable examples. Simple graphical techniques are used for verifying the independent and identically distributed (IID) assumption for the data set. The error introduced due to the use of the exponential distribution in place of more appropriate distributions in estimation of availability and reliability characteristics is analysed.

Jan 1, 1989

By Zachary D. Jones

"Construction projects involve a great many risks. The risk that material prices will increase during construction or that the work under construction will be destroyed by fire, storm or some other act of God are just a few examples. In tunneling or other underground projects, one of the most significant risks is that the subsurface conditions encountered during construction will differ from what is expected. Each of these risks must be accounted for, managed and, ultimately, the duty of one party or the other to bear. The primary tool used to allocate the risks among the parties is the construction contract.How construction contracts allocate the risk that subsurface conditions will differ have changed substantially over the past century. Today, construction contracts typically allocate the risk through a series of provisions. The first is the differing site condition or changed condition clause. That clause, when included, typically provides that the owner bears the risk that the subsurface conditions will differ from what is indicated in the contract documents or what is reasonably expected. The second clause is one that provides that the contractor must conduct a reasonable site investigation and bear the risk of any conditions that such an investigation would reveal. The third provision includes disclaimers that are often included in geotechnical data provided by the owner (or the owner’s engineer) to the contractor which attempts to limit the information on which the contractor can rely. Because these risk-allocating devices seem to be somewhat conflicting, a brief discussion of each provides critical insight in understanding how the modern construction contract allocates the risk of differing site conditions.At the start of the 20th century, construction contracts looked substantially different than they do today. For example, one contract for the construction of a public water tunnel in Chicago, IL, drafted around 1895 contained the following clause:The contractor must take the work entirely at his own risk. No extra allowance will be made for quicksand, hardpan or boulders."

Jan 1, 2014

By John R. Lotz

DEVELOPMENTS in Iran currently arousing interest in a considerable portion of the world, particularly on the part. of that country's immediate neighbor on the North and in our own country, an inseparably related to and largely dependent upon the government's attempts to strengthen its economy and improve the standard of living of its people. These efforts are encompassed by provisions of the Seven-Year Development Plan recently enacted and not, in the process of implementation. It is a fine example of what one financially sound but extremely backward and poorly equipped country has undertaken to do on its own account and with its own resources. This Seven-Year Plnil was formally authoriztld by an act of the Iranian Parliament in February 1948. Its stated objects are to carry out such plans for the development of the country and its economy as ail1 raise the standard of livinc: and standard of education of the people, and re- duce the cost of living. A seven-yrar program for carrying out the work within the limits of appropriations was assigned under the law. The total amount to be expended during the seven- year period was fixed at the equivalent of $670 millioil at current rates of exchange.

Jan 1, 1950

By Stanislatv Pawlowski

New, large sulphur deposits were discovered in Poland in 1953, the result of investigations by the National Geological Institute. All deposits occur in a widespread Miocene evaporite unit in the Carpathian foredeep. The gypsum underlying impermeable Sarmatian clays was altered to limestone and native sulphur where penetrated by hydrocarbons and bacteria. All deposits occur in Miocene structural uplifts. The early determination of the genesis of the sulphur deposits and their occurrence in elevated blocks led to an exploration program that successfully located new deposits.

Jan 1, 1978

By R. A. Hemstock

AREAS in which the surface de-posits consist of organic material -known in some parts of Canada as muskeg and in Europe, more generally, as peat lands -have long been some of the least rewarding of lands of the north temperature zone. Even in such countries as Great Britain, Holland, and Denmark where a good deal of incentive exists to develop all available land, the use of peat land has been negligible except as a source of fuel. Only recently have efforts shown promise in re-claiming these lands for farming or for forestry. Russia has large areas of peat and use is made of it for power generation. The Russian people have also ?developed a variety of machines for handling peat, which would indicate that they are well ahead of the Wes tern World in their technical and physical ability to solve some of the problems. Certainly in Canada, where there are over 500,000 square miles of muskeg, the economic aspects of this problem are important. This is especially true in considering the shifting emphasis to northern development. Not only is muskeg in possession of great stretches of terrain, thereby rendering it useless for agricultural purposes, but it is apparently moving into forested areas and reducing their productivity. In addition, it lies as a great barrier to movement in the search for and development of such natural resources as petroleum, natural gas and minerals generally. This situation has long been recognized in Canada but only recently have organized efforts been made to study the problems and search out ways of overcoming them.

Jan 1, 1958