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By David G. Kidd

The principles of Ore Sorting in general and photometric sorting in particular are discussed with detailed reference to the Model 16 machine. The operating principles and design of the Model 16 are discussed and a case study presented to demonstrate the use of sorters to process an industrial mineral. In addition, an economic study is presented, to highlight the benefits of ore sorting, by evaluating the increased revenue that can be achieved using an ore sorter to process a particular ore body.

Jan 1, 1983

By W. B. Boggs

A paper describing the Noranda smelter was presented at the 1930 annual meeting of the Institute (1). A lacer article appeared in the Trans-actions of the A.I.M.&M.E. in 1933. Since that time there have been many changes and improvements in plant operation and it is the abject of this paper to give an account of developments up to the beginning of 1939. The Noranda smelter was built originally for a capacity of 30,000 tons a month. At present, the average tonnage being treated is 110,000 tons a month, the tonnage of custom ores alone amounting to almost the total rated capacity of the original plant. This increase has been accomplished by increasing the capacity of the reverberatory furnaces from 700 tons of solid charge per furnace day in 1928 to 1,500 tons per day at the present time. In 1935, it appeared chat the limit of furnace capacity had been reached at about 1,300 tons of charge per day because of the short life of the sprung silica arches. However, the adoption of the suspended magnesite roof, which had been developed at the Flin Flou smelter of the Hudson Bay Mining and Smelting Company, overcame this difficulty and it is believed that the limit of the capacity of the present reverberarory furnaces has not been reached. A brief account of the changes to equipment in the various departments will be given, followed by a description of the more important features of present smelter practice.

Jan 1, 1939

By T. Winkler

This paper presents elements of the Virtual Working Environment for identification of hazards occurring in the mining industry. The Virtual Working Environment includes models of machinery and models of anthropometric features. Examples are given for identification of technical hazards at the design stage using the following computer programs: Finite Elements Method, Multibody System Analysis and Human Body Modeling. One of the methods to improve work safety at the machine and equipment maintenance stage is to share design and operational knowledge in a form of an Interactive Electronic Technical Manual (IETM). An IETM is created using so-called reusable knowledge elements connected by relationships. A metamodel created in Unified Modeling Language is one of the forms for description of these relationships. The metamodel can represent, for example, interrelations between elements of repair procedures. Examples of procedures realized during the replacement of a damaged cutting bit are presented and discussed.

Aug 1, 2013

By T. Johnson

Mining activity in a number of metal ores has been running quite high over the last few years. In particular, those metals that employ acid functional extraction processes such as copper, nickel, cobalt and uranium have been particularly active. The world?s largest nickel mine ? the massive $4.76 billion Ambatovy nickel mine on the African island nation of Madagascar is nearing completion. When it reaches its full production capacity in 2013, the mine will produce 60,000 MT/yr of nickel and 5600 MT/yr of cobalt. Coming on the heels of the Ambatovy project is the Long Harbour Processing Plant in Newfoundland, Canada which will process the ore from Vale?s Voisey Bay mine in Labrador. Voisey?s Bay is expected to generate more than 50,000 MT/yr of nickel ore when it starts up in 2013. Next up will be the Boleo project in Mexico on the Baja peninsula. When commissioned in 2013, the $1.4 Billion Boleo project is expected to produce 60,000 MT/yr copper, 3100 MT/yr cobalt, 36,000 MT/yr zinc and 100,000 ? 250,000 MT/yr manganese carbonate.

Feb 27, 2013

By W. P. Arnott, P. Nascimento, X. L. Wang, K. C. Kocsis, S. J. Taylor, H. Firouzkouhi

We report the first spectral photoacoustic measurements of silica, coal, and kaolinite dust absorption coefficients from 11 to 13 μm at 5 nm resolution made with a tunable quantum cascade laser. This is important because airborne silica dust and coal dust within mining environments continue to be a problem for mine workers and staff due to their severe health effects on the respiratory system, while other dust types are potentially interferents to their detection. Our real-time spectra compare favorably with the non-real-time filter-based Fourier transform infrared spectrometer (FTIR) spectra obtained using the sampling system developed by NIOSH for their end-of-shift method to determine silica dust concentrations using a portable FTIR. We discuss our new dust generation system and instrument testing chamber. We also show that our PM4 silica mass concentration measurements by a low-cost air quality sensor (SPS30) are in good agreement with the TSI Aerosol Particle Sizer instrument, the NIOSH end of shift method, gravimetric mass, and correlate well with photoacoustic light absorption measurements at a wavelength where silica absorbs strongly.

Aug 20, 2022

By William W. Kephart

Brockway Glass Company, Inc., manufactures glass containers at fourteen plants located in nine states. The relatively high place value of the major glass batch components dictates that raw material supplies be obtained from numerous sources in the United States and Canada. One objective of our central composition control program is to arrive at a glass composition with similar physical properties at each of our plant locations. This requires that adjustments be made in the batch compositions to compensate for chemical variations from one raw material source to another. Minor chemical variations will occur in sand, limestone, and dolomite from one source to another. Major variations are present in the alumina sources because of the diverse rock types utilized.

Jan 1, 1973

By V. Matthews

"INTRODUCTION Typical grinding electrification requirements are defined by high power, constant torque and slow speed. Dual pinion mills also include a need for tight tolerances in torque between the two motors, to avoid overloading any single motor. Standard induction (asynchronous) motors have often been used but only in combination with mechanical gearboxes (reducers), required to reduce process speed to the correct level for mill pinions. The gearbox introduces added system complexity, capital cost, maintenance and energy cost due to mechanical losses. SYNCHRONOUS AND ASYNCHRONOUS MOTORS Elimination of the gearbox requires a motor designed to operate at a very low speed (rpm). Traditionally, mill motor requirements were best served by synchronous motors. The benefits of synchronous motors include- • Higher Efficiency (no conductor losses in rotor) • Very high power at low speed • Flexible Power factor (leading or lagging) • Constant speed (not load dependent) • More accurate speed control Synchronous motor cost is higher due to construction complexity, need for exciter and excitation panel, brushes, brush lifters. Figure 1 represents the equivalent circuit for a synchronous motor.Asynchronous motors, also known as squirrel cage induction motors, are singly excited, per Figure 2, the resulting equivalency circuit is less complex and only in need of a single voltage source.Commonly, a DC voltage supply is connected to the rotor (both physically and electrically) via brushes. The DC voltage enables the production of flux in a single direction. The brushes are connected to rings. The slip rings encircle the rotor but are insulated from the rotor. The slip rings are connected to a rotor winding known as a field winding. On large motors, brushless exciters are often used. A brushless exciter is a small AC generator whose field circuits are mounted on the stator and armature circuits are mounted on the rotor shaft. The exciter generator’s 3-phase output is rectified to DC by a 3-phase rectifier (mounted on the shaft) and fed into the main DC field circuit. It is possible to adjust the field current on the main machine by controlling the small DC field current of the exciter generator (located on the stator). [1] Brushless synchronous motors are often preferred over the traditional brush design but introduce additional complexity to motor construction in the form of additional windings and rectifiers comprising the excitation circuit. It stands to reason that because of the additional complexity, a synchronous motor will be higher in cost than an equally rated asynchronous induction machine."

Jan 1, 2015

By Donald Carlisle

"IntroductionTHE OPINION is held by many persons outside the mining industry, and by some within it, that mine •operators customarily find it advantageous to mine •only the richer parts of orebodies and to leave behind, perhaps permanently, leaner material which could be mined only at a lesser profit. This opinion and the inference which might be drawn from it that 'gutting' of mineral resources is a common feruture• of the mining industry are prejudicial to the intertsts of the industry and deserve careful scrutiny. Oddly enough, a theory of mine economics which gives much support for the opinion was advanced first by members of the mining profession itself, has been repeated •several times in mining literature, and to my knowledge has never been adequately refoted.According to the theory, selective mining of the rich ore first on a large scale will yield substantial gains and these gains do not merely reflect the desire of 'money minded investors' for a quick return but derive from the logical application of compound interest rates and the concept of ;present value. W. O. Hotchkiss and R. D. Parks (1) illustrate the reasoning with a hypothetical example in which an orebody of 4,000,000 tons may be mined either in its entirety in forty years at $1.00 per ton profit or selectively with the recovery of only the richest half in twenty years at $1.50 per ton profit. They show that, with Hoskold rates of 4 and 8 per cent, the present value of profits from mining only the richer 2,000,000 tons exceeds the present value of profits :from mining the whole orebody by about 20 per cent."

Jan 1, 1953

By C. W. Baxter

Eveleth taconite company was formed in 1963 to mine and beneficiate taconite on the Mesabi range of Minnesota. Its thunderbird mine is located midway between the cities of Eveleth and Virginia, Minnesota, and the crude ore is transported by rail to its Fairlane plant approximately ten miles to the south of the mine, "figure 1". As is implied by the names of the mine and plant, the ford motor company is the principal owner of Eveleth taconite company, with an 85% interest, Oglebay Norton company holds the remaining 15% interest and also is the managing agent.

Jan 1, 1972

By James R. Boyle

The mining methods and practices used at the Young zinc mine, American Zinc Co. of Tennessee, have resulted in a low-cost, high-yield operation. Zinc ore (sphalerite) occurs in limestone-dolomite beds of the Kingsport Formation and is mined by modified room and pillar method. Utilizing trackless mining equipment which incorporates a high degree of flexibility, this operation has had a steady increase in productivity.

Jan 1, 1965

By Lloyd B. Underwood

In the event of a sudden nuclear attack upon the United States, it is imperative that vital command and control centers have a high probability of survival. One such vital facility is the North American Air Defense Command Combat Operations Center at Colorado Springs, Colorado. Known briefly as NOW, this installation when completed will be housed in large chambers excavated out of granite beneath the eastern slope of Cheyenne Mountain (Figure 1). The NORAD COC, a U. S. Air Force sponsored project, will serve as the primary collection and evaluation center for data concerning unknown aircraft, missiles, or space vehicles, which might bring destruction to North America. The data will be fed into high-speed computers and electronic equipment from outpost sources - radar, ballistic missile early warning stations and picket ships throughout the world. Electronically controlled display boards will make it possible to evaluate the tracking data instantaneously and to take appropriate defensive action1.

Jan 1, 1965

By J Leem, S Mehrishal, J Kim, A Fereshtenejad, J Song

Rock mass discontinuity mapping plays a crucial role in developing a reliable Discrete Fracture Network (DFN), providing insights into the distribution of geometrical and mechanical properties of discontinuities. This enables an accurate assessment of geotechnical infrastructure and mining excavations. Data obtained through conventional mapping approaches are substantially limited by factors such as accessibility and subjectivity. Moreover, these conventional methods may pose inherent risks due to manual techniques, exposing practitioners to potential dangers. Recent digital developments in remote surveying techniques offer opportunities for safer and more reliable rock mass discontinuity surveys. These technologies allow extensive three-dimensional surveying and the production of high-resolution 3D surface models, applicable at any time. This paper presents a workflow for digital discontinuity mapping employing drone technology and photogrammetry. Additionally, the capabilities and challenges of applying artificial intelligence (AI) algorithms in the rock mass discontinuity characterisation process are discussed.

Sep 1, 2024

The importance of the accurate determination and interpretation of the bulk density and porosity of a given iron ore deposit is very often disregarded or neglected. Large amounts of time and money are spent on delineating and testing orebodies, and yet one of the most important factors in resource evaluation is sometimes estimated or, at best, determined from existing data from similar deposits. The Thabazimbi and Sishen South iron ore deposits are two well-known economical occurrences of high-grade iron ore in South Africa. Both these deposits formed as secondary enrichment of banded iron formation lithologies. Ongoing density studies on both these deposits are underway and results thus far proved very effective and necessary. Small-scale methods are used to determine average values for different ore types on both deposits. These values are used in resource estimation and geophysical interpretation.

Jan 1, 2007

By C. R. Stephan

There are a large number of facilities throughout the world which handle coal, such as preparation plants. Many other facilities use coal as a fuel, such as cement and lime factories. Although coal can be handled safely and can be an efficient fuel, there are explosion hazards which are accentuated as the particle size is reduced. Particle sizes of coal which can fuel a propagating explosion occur within thermal dryers, cyclones, baghouses, pulverized-fuel systems, grinding mills, and other process or conveyance equipment. This paper discusses how explosions can occur within these facilities.

Jan 1, 1998

By Lloyd M. Kniffin

[This paper is one of series being prepared by the United States Bureau of Mines on mining methods, practices, and costs in the various mining districts of the United States. It describes the mine of the Hanover Bessemer Iron & Copper Co. at Fierro, Grant County, N. M., which is the only operating iron mine in the southwestern part of the United States. This mine is in a district noted for the great variety of ores that it produces. Within a small area, as shown is Figure 1, there are noteworthy deposits of nearly all the common metals. The ore occurs in lenticular masses dipping at about 50°. An underhand stoping method has been developed that requires but a very small amount of handling of ore. As the ore is very irregular in iron content and also in the distribution of the impurities--chiefly sulphur, silica, and magnesia--a method has to be used that will permit selective mining and will also allow ore and waste to be taken out separately as conditions change. A magnetic cobbing plant raises the grade of the ore shipped about 10 per cent.]

Jan 1, 1930

By Essie Esterhuizen, Michael M. Murphy, Chris Mark

"The design of underground coal mines requires a clear understanding of the overburden response, the loading of pillars, the loading of the gob, the pillar failure process, and the ultimate load carried by partly or fully yielding pillars. Very few highquality stress measurements of yielding pillars and gob loading have been made in full extraction mining. Well-calibrated numerical models can assist in providing a better understanding of the load and failure processes, provided the coal, the overburden, and the gob are all modeled with sufficient realism. A program of numerical model calibration and validation was carried out using FLAC3D.1 The models were calibrated against observed and measured performance of coal pillars and the overburden in operating mines to provide a basic set of input parameters that can be used to provide a realistic first estimate of expected ground response and pillar loading. Input parameters for modeling coal pillar response were based on data from triaxial testing on coal samples, combined with both matching the depth of failure in the coal ribs to observations as well as matching the peak pillar resistance to an empirical equation. The models were calibrated against strong roof and floor case histories in which the pillar strength is governed by failure and yielding of the coal within the pillar and the surrounding strata only had a limited impact on pillar strength. Input parameters for the overburden were determined from a large database of laboratory tests and model calibration against maximum subsidence and subsidence curvature. Further overburden calibration was carried out by matching stresses in the mining horizon to field measurements. Three examples of the application of the calibrated dataset and modeling methodology to field measurements are presented. The results show that a reasopable estimate of the in-seam stress distribution and overburden response can be obtained for both strong and weak overburden scenarios at various depths of cover.INTRODUCTIONThe planning and design of coal mine excavations requires reliable estimates of the expected strength and loading of the mine structures to achieve global stability. Empirical methods are widely used to estimate the strength and loading of coal pillars and have been incorporated into pillar design procedures, such as Analysis of Longwall Pillar Stability (ALPS) (Mark, 1987) and Analysis of Retreat Mining Pillar Stability (ARMPS) (Mark and Chase, 1997), that are widely used in the United States. ~umerical models are finding increasing application as a tool for underground mine design because of their. versatility and the ever increasing computational power available to mine designers. A prerequisite for the application of numerical models is the calibration of the models against observed rock mass response (Hoek et al., 1990; Skiles and Stricklin, 2009). The calibration process may include comparison of model results to measured stress and deformation and modifying the input parameters in a systematic manner to achieve a satisfactory agreement between the model results and measurements. Once models have been calibrated, they can be applied to evaluating similar mining layouts in similar geological conditions."

Jan 1, 2010

By G A. Blengini, S V. èolar

The minerals industry is faced with choices beginning in the exploration phase and extending over the life cycle of the mine. Firms examine the technical feasibility of alternative actions and typically rank them based on economic performance. Increasingly firms also consider alternativesÆ contribution to sustainable development. There are many visions of what a sustainable future should look like and much debate about what should be sustained. Sustainability is a process, a series of incremental actions, and each alternative course of action has the potential to further progress toward one or more sustainability goal. However, because it is not possible to sustain everything everywhere simultaneously, trade-offs and choices inevitably have to be made.Sustainable decision making before investment (ex ante decisions) should incorporate a broad suite of quantitative and qualitative information. One approach is to utilise an integrated sustainability assessment (ISA) framework that supplements traditional technical and financial tools with other tools such as objectives hierarchies (OH) and life cycle assessments (LCA). OH is a problem framing method that captures stakeholder and decision maker interests, objectives and values. LCA addresses material and energy flows, and environmental impacts. The outputs of these tools can be combined with additional qualitative measures and analysed using multi-criteria decision analysis (MCDA). MCDA models facilitate comparison of different alternatives on the basis of a set of criteria and indicators. Some can incorporate information on risk attitudes and preferences ( multi-attitribute value theory models) and others uncertainty about outcomes (multi-attribute utility models). Studies have been published describing and comparing tools for minerals sector decision analysis. Our paper extends this literature, discussing how a combined OH-LCA-MCDA can support ex ante sustainability assessment by incorporating preferences, risk attitudes, and monetised or non-monetised social and economic variables, in a manner that captures their inherent complexity. We also discuss how such a combined model would support trade-off analysis.

Jan 1, 2009

By David Burchell

Duckbill mining is probably the simplest method of loading coal mechanically at the face in underground mines. It is a means of reducing the amount of physical labour required to produce a ton of coal. In effect, it is merely shaker conveyor mining brought up to date with the addition of a self-loading head or 'duckbill' on the end of the conveyor line. Any mechanical device used to load coal is a means of supplanting the human muscles as the medium for getting the coal off the floor into the transportation equipment. There can be no argument with the conclusion that a man can lift so much and no more. He can load more tons of coal on a low conveyor, because the lift is less, than he can in a pit car two, three, or even four feet high. Thus it follows that, if the lifting operation is entirely eliminated, the man should be able to produce even more coal. A mechanical operation is essentially a multiplication of physical strength. Although there are various ways in which coal can be loaded at the face by mechanical means, there is, perhaps, none more adaptable than shakers equipped with duckbills. This is particularly true for thin seams and in mines having heavy, tender top conditions which require close timbering. However, as we are discussing duckbill mining, we will make no further reference to any other type of equipment. The first, and to date the only, mine in eastern Canada to adopt a system of mechanical loading at the face is the Franklin mine of the Bras d'Or Coal Company, Ltd., at Bras d'Or, N.S. An experimental Goodman shaker conveyor with a self-loading head, or duckbill, was installed in this mine in 1940. Since that time other units have been placed in operation so that, today, this mine is completely mechanized. The method of operation 1s room-and-pillar. The operation is carried on in a 42-in. seam, which lies 420 feet beneath the Sydney Main or Harbour seam in the Sydney Mines basin. The slopes bear N.25 30'E., dip 10 per cent seaward, and are about 6,000 feet in length. The physical conditions of this seam do not make it particularly adaptable for complete mechanization as it contains a large amount of foreign material, such as clay intrusions or wash-outs and iron pyrites. These clay intrusions, known locally as 'troubles', vary in thickness from a few inches to as thick as eighteen feet and usually replace the coal to the full height of the seam.

Jan 1, 1947

By J. P. Bunch

As the number of environmental laws continues to steadily increase and the economic penalties for contamination problems become more severe, environmental management represents an important management function within today's U. S. mining industry. The economic impact to a mining company for contamination is not only realized in legal fees and fines but also in the cost of doing normal business. For example, a mining company with contaminated property applying for a loan may be refused because of a lending institution's reluctance to finance due to liability concerns. Or, an insurance company may decide to greatly increase its annual premiums because of existing or potential contamination problems. One of the main duties of the environmental manager is to seek ways to reduce these types of problems by eliminating contamination or by knowing what problems exist and designing corrective measures to prevent the situation from worsening.

Jan 1, 1990

Norton Co., a manufacturer of abrasive products and diamond drilling and coring bits for oil and gas exploration, is building a $19.1 million addition, scheduled for completion in late 1980, to the Huntsville, AL. The plant makes alumina-zirconia abrasive grains used in grinding wheels and coated abrasives. ALUMINUM Martin Marietta Aluminum Inc. announced plans to expand production capacity of its 112,000-ton-per-year primary aluminum smelter at Goldendale, WA to 177,000 tons per year. The $125 million expansion was scheduled to come onstream in 1981. The Aluminum Company of America announced plans to restart a fourth potline during October at its 185,000-ton-per-year Point Comfort, TX primary aluminum smelter.

Jan 1, 1979