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By John L. Stafford

The ROEMMC combustion system was originally conceived as a means of utilizing solid fuels that would otherwise have been wastes requiring disposal and convert these fuels into useful energy sources. This concept follows as an extension of the application of residual waste incineration with energy recovery practiced in the lumber, manufactured board, sugar cane, and other industries. The incineration of these wastes in the furnaces of steam generating equipment is thoroughly described (1, 2, 3, 4, 5, 6, 7). The fundamental principle of the ROEMMC system is temperature control which makes possible the maintenance of the non-combustible fraction of these solid fuels in a dry solid state and their separation from the gaseous products of combustion. This philosophy of ash removal and the "slagging" philosophy are compared. The ROEMMC equipment function and applications are described.

Jan 1, 1978

By A. Röttger, W. Theisen, J. Küpferle, M. Alber

"Wear of TBM tools significantly affects tunneling advance rates. Wear-prediction models are based (amongst others) on the abrasivity of the present geology, which is determined via laboratory tests. To evaluate the results from such tests in context, this work considers the tribological system TBM tool from a materials technology perspective. In so doing, the microstructures of different application-oriented materials are presented and discussed in terms of their wear behavior and wear resistance. The significant influence of tool materials on the abrasivity of the geology and thus wear prediction models has already be identified. LCPC, Cerchar and nano-scratch experiments have been performed as confirmation. Material-dependent wear mechanisms and their correlation in terms of tunneling have shown that it is mandatory to consider the complete tribological system to estimate the wear of TBM tools. 1 INTRODUCTION Mechanized tunneling is vital to ensure necessary infrastructure development in megacities like Tokyo (Bay Tunnel), Istanbul (Eurasia Tunnel) and Mexico City (Tunnel Emisor Oriente). The use of Tunnel Boring Machines (TBMs) has been established for many years. In contrast to other methods such as boring and blasting or excavation using dredgers, tunneling with TBMs allows simultaneous excavation and removal of both the mineral and tunnel lining by tubbing segments or shotcrete. This makes tunneling more efficient, allowing for faster development of the tunnel in both hard rock and soil [1]. When budgeting such tunneling projects, precise planning and coordination in terms of tunneling technique choice (e.g. EPB or Slurry-shield), the relevant geology, and the associated penetration rates and tool wear are required. In particular, wear to TBM tools has a significant impact on tunneling progress. Due to wear, tools become dulled or lose their functionality because of brittle material behavior, thus reducing penetration rates and therefore tunneling efficiency [1]. As a result, additional tool changes are necessary, leading to higher overall costs due to down times and maintenance costs. Therefore, there is strong interest in a reliable and precise wear prediction model for TBMs. As already mentioned, the geology and associated wear of the tunneling tools define the maintenance times."

Jan 1, 2016

By C. Cristoffanini

A real-time transient pipeline simulation was used to model the operational pressure response in the concentrate and tailings pipelines of the Minera Los Pelambres copper mine in Chile. A high-fidelity simulator was needed to train the operators on safe operation of the pipeline for different scenarios. A simulator that solves the transient equations was used to dynamically predict the pressure and flow throughout the pipeline to provide real-time responses to operational changes such as opening or closing a choke valve, or sending a water batch. Slurry rheological properties were incorporated into the model. This paper presents the technical background of the pipeline simulation model and the study of slurry properties. The paper shows the results of the transient simulation for different operating scenarios such as start-up, shutdown and leakage, by presenting the hydraulic gradient curves for each case. Finally, the paper briefly presents how the simulator was connected to an emulated control system and used to train the operator, it demonstrates the most effective tool available to learn to resolve undesirable conditions.

Feb 23, 2014

By P. Walshe

A common belief among Itlnl.ng operators today is that computer based truck m:mitoring and dispatching systems are only applicable to, or affordable by, very large scale open pit mines. Before the advent of microcomputer technology this belief was generally a valid one. Microcomputer technology as it currently exists has reached a high level of sophistication and capability, rapidly approaching that of the minicomputer standard. When coupled with reliable software and data communications packages, it now provides the means to make truck monitoring and dispatching a viable and attractive management aid to mines of all sizes. This paper briefly addresses the evolution and current state of computer truck dispatching and examines a microcomputer based system in this context. To demonstrate the effectiveness of this approach to truck dispatching a recent installation in a medium sized mine is presented. Preliminary field data from the case mine are presented to illustrate the methodology.

Jan 1, 1989

By Chester O. Ensign

The White Pine Mine is situated in the southwestern portion of the Keweenaw Peninsula of Upper Michigan approximately 6 miles south of Lake Superior (Fig. 1). It is east of the Porcupine Mountains in Ontonagon County. The ore deposit is about 70 miles southwest of the famous native copper deposits of the "Copper Country" lying northeast of Houghton. Geological conditions are different at every mine and create a special set of problems in dilution control. This paper is largely intended to describe the techniques applied in mine dilution control (grade control) at White Pine, and present results of the program. For necessary background information major geologic characteristics of the deposit, particularly those that exert control over the distribution of ore, are briefly discussed. Mining methods are described in considerable detail since applied grade control techniques are adapted to these.

Jan 1, 1964

By J. C. Cawley

Improvements in today's maintenance practices are mandatory as more complex and productive machines evolve in the mining industry. By keeping machine reliability high, through improved maintenance procedures, overall mining costs can be reduced. The Bureau of Mines is investigating diagnostic maintenance systems for underground mining machinery. A hydraulic expert diagnostic system and an electric motor predictive diagnostic system have been designed and installed on a Joy 16CM continuous miner. An electrical diagnostic system has been designed and installed on a Joy 14CM continuous miner. Each system is functionally described and the relative merits of expert diagnostic systems versus algorithmic diagnostic systems are discussed.

Jan 1, 1991

By Peter Riba

Up until ten years ago the industry had arrived at a relatively conventional, and consistent design of coke ovens. Through the years the designers and builders were not being heavily taxed to come up with revolutionary new designs. However, the stimulus for design change was ever present. These stimuli for change are quite important and they are the driving force which produce improvements. The most obvious stimulus to change a design is commercial. To "build a better mouse trap and the world will beat a path to your door" is the well used cliche which best befits this philosophy. As in all businesses, coke oven designs require that all of the considerations, which affect the cost or the desirability of the design, be optimized. One way to increase the desirability of the particular design, 1s to make the design in- expensive to operate. Or, put another way, to increase production for the same operating cost

Jan 1, 1980

By James J. Scott

Three dimensional photoelastic techniques have been developed which provide information on the state of stress at any point in a model investigated. This investigation utilizes these techniques to determine the stress distributions in the pillars and the roof of a room and pillar mine model. Castolite plastic was used for the construction of the model in which a stress pattern was developed by the stress freezing process. Analysis of the stress pattern was accomplished by use of data obtained by observing points in slices from the model with a polariscope and solving data obtained by' the shear-difference method. Slices through the centerline, edge of pillar and centerline of span were investigated. Results of this work provide information on the overall stress distribution on points of stress concentration in compression, shear and tension, show relative magnitude of stress throughout the model and indicate directions of the most important stress values. A generalized roof bolt pattern is developed for room and pillar mines based on the stress distribution. A digital computer was used in the reduction of data and proved to be extremely useful for investigation of this type.

Jan 1, 1963

By Richard D. Begley

This paper will present the results of an analysis of several abandoned coal mine projects and includes field data for over a dozen different reclamation projects recently completed in the state of West . Virginia. The analysis was performed with the objective of summarizing and or classification of the environmental consequences with reference to the characteristics of the mining facilities (surface, underground, etc.). The analysis also addressed the itemized cost of remediation with respect to procedures, environmental concerns and time. The results of the analysis are that each abandoned coal mine site in West Virginia have/had many unique features and in most cases include a combination of environmental concerns that complicate comparisons. The study also revealed that the abandoned mine land program for mines abandoned prior to 1977 that is being financed by a tax on the production of coal, has produced many benefits for the state of West Virginia. This grant program administered by the Office of Surface Mining, has resulted in a high quality methodology of remediation that has been successful for many years in greatly minimizing and/or eliminating environmental concerns from abandoned coal mines.

Jan 1, 1997

By Dairo E. Chaverra, Carlos Argumedo‑Jimenez, Oscar J. Restrepo‑Baena

This paper presents the results obtained by processing a gold and silver telluride mineral concentrate from a mine in Colombia. An acid wash, also known as acidification, was carried out, followed by oxidation with nitric acid as a pretreatment. Cyanidations of the pretreatment residues were carried out and the results were compared with results from cyanidations of base materials. The removal of carbonates in the acidification, a tellurium extraction close to 90% during the pretreatment, and a 30% improvement in the gold recovery compared to the conventional process were achieved.

Nov 8, 2023

By E. A. Twichell

An entirely new concept in the effective utilization of magnetic, energy has resulted in a major break-through in the design of magnetic separation equipment. One of the first applications of this concept has resulted in the development of a Permanent Magnetic Wet Drum Separator with strength .and operating characteristics equal to Electro Wet Drum Separators. Prior to this development when strength and adjustability were required, electro wet drums were specified even with all their drawbacks. The electros, by nature, are subject to coil failure or burnout, over-heating and loss of strength, high power consumption and generally high maintenance. Now the high strength and the adjustability, formerly the exclusive property of electros, has been engineered into permanent wet drum separators. These units combine maximum field strength in the separation zone with strength adjustment to suit changing conditions. Adjustment can be effected while the drum is in operation without stopping either the feed or the drum.

Jan 1, 1967

By Herman L. Bauer

The Robinson Mining District near Ely, Nevada, is one of the major porphyry copper districts in the world. Within the district is an east-trending zone of altered porphyry, metamorphosed sedimentary rocks, and sulphide mineralization surrounded by Paleozoic limestone, dolomite, shale and sandstone, Tertiary volcanics, and Quaternary alluvium. Six major disseminated ore deposits have been exploited in this eight-mile zone. About 20% of the district production has come from disseminated ore in metamorphosed sedimentary rocks found adjacent to altered quartz-monzonite porphyry. The following brief statements summarize the inter-relationship of porphyry, alteration, metamorphism, and mineralization: 1. Disseminated copper ore does not occur in unaltered porphyry or in unmetamorphosed sedimentary rocks 2. Sedimentary rocks have been only weakly metamorphosed where intruded, by unaltered porphyry. 3. Intensely metamorphosed sedimentary rocks are found only adjacent to, altered porphyry. 4. Many hydrothermal minerals are common to both altered porphyry and adjacent metamorphosed sediments. 5. Disseminated ore is found in altered porphyry and adjacent meta¬morphosed sedimentary rocks. 6. In general, there is a direct correlation between grade of ore in porphyry and copper content in the adjacent rocks. 7. Chemical changes in the altered porphyry facies and metamorphosed rock facies appear to be related:

Jan 1, 1963

Water contact angles in the air/water/francolite, fuel oil/water/francolite and fuel oil/water/quartz systems were measured to describe the wetting characteristics of these minerals. It was found that white francolite is more hydrophilic than black and tan francolite both in the absence and presence of fatty acid addition. The contact angle measurement results do not correlate very well with the flotation response and it appears that kinetic aspects of the bubble attachment process play an important role in the francolite-fatty acid flotation system.

Jan 1, 1997

By J. D. Miller

On the basis of nonequilibrium zeta potential measurements by laser-Doppler electrophoresis, the sign of the surface charge of alkali halides in their saturated brines has been established. The results are generally as expected from simplified lattice ion hydration theory. This recent electrokinetic information coupled with the stability and prevalence of collector colloids in such soluble-salt flotation systems suggests that the selective flotation of alkali halides is due to the adsorption of oppositely charged collector colloids by heterocoagulation. Experimental flotation results confirm this surface-charge/collector-colloid adsorption model and are presented herein.

Jan 1, 1992

By M. L. Harris, I. Zlochower, M. J. Sapko, I. E. Perera

Experiments conducted with limestone dusts and dolomitic marble dusts have indicated that when rock dust is wetted and subsequently dried, it becomes a solid, non-dispersible cake. However, in order to be effective, rock dust must be able to disperse as individual particles to inert. To counteract this, rock dust manufacturers created treated rock dusts that will resist caking after moisture exposure. National Institute for Occupational Safety and Health (NIOSH) researchers conducted a series of laboratory-scale experiments on four base rock dusts and their treated counterparts to assess the effectiveness of various anti-caking additives after being exposed to moisture and then dried. The dusts were exposed to moisture using humidity cabinets having a high relative humidity (99% RH) and by also exposing the rock dust bed to water through bottom wicking. The dusts were then evaluated for dispersibility after drying using the NIOSH-designed dust dispersion chamber. The anticaking additives were different concentrations of stearic acid, oleic acid, and xylene-based surfactants. All results were compared to a reference rock dust used to conduct large-scale experiments in the Lake Lynn Laboratory (LLL), Fairchance, PA. When the untreated dusts were dried after exposure to moisture for one day, no dispersion was measured. However, rock dusts treated with anti-caking agents were readily dispersible even after exposure to moisture for six months. This report details the analysis and characterization of anti-caking additives using the NIOSH-designed dispersion chamber and the 20-L explosion test chamber. INTRODUCTION In order for a coal dust explosion to propagate, five elements are required. In addition to the fire triangle in which three elements are necessary to sustain a fire—fuel (coal dust), heat (ignition source), and an oxidizer (oxygen in air)—a combustible dust explosion requires dispersion of a dust cloud (pressure wave) and confinement of a dust cloud (underground mine entry) (1). Coal dust explosions can originate anywhere in a mine. For example, when a small volume of a flammable methane and air mixture is ignited in a closed end, the high-temperature gases rapidly expand to create a pressure wave, sometimes referred to as a “pioneer wave,” that may steepen into a shock wave as it propagates away from the ignition source. The shock wave produces a wind that disperses the dust preferentially from any elevated and exposed surfaces (roof, ribs, belt structure, cribbing, etc.). Factors that are known to affect the intensity of an explosion are the dust particle size, the location of the dust within the entry, the dust dispersibility, and the volatility of the coal dust (1). Particles less than 75 μm (< 200 mesh) in size are most reactive (2). Dusts that are located on the roof, ribs, and elevated surfaces are more readily dispersed than dusts on the floor. Therefore, application of quality rock dust in sufficient quantities is essential to inert coal dust and to prevent continued flame propagation. 30 CFR 75.402 and 75.403 require 80% total incombustible content be maintained within 40 ft of the face, and 30 CFR 75.2 defines rock dust acceptable for use in underground coal mines. It also defined that “when rock dust is wetted and dried, will not form a cake”.

Jan 1, 2019

By K. E. Harrison

Acid rain legislation as proposed by President Bush [1], if enacted, will immediately refocus current thinking on the economic decision-making as related to coal preparation facilities. Unit operations currently ignored because of their costs, will become mandatory to coal plant designers and operators to ensure maximum energy recovery and sulfur reduction in the entire coal stream. In anticipation of this need, the U.S. Department of Energy, The Ohio Coal Development Office, EPRI and others are sponsoring research in several areas of coal preparation, and coal plant designers are beginning to consider more innovative techniques as they configure their flowsheets for plants of the future. Preparation plants then will have recleaning

Jan 1, 1990

By Donald J. Hill

To be successful, every organization within the mining industry must involve itself in researching and evaluating methods of loss control. The appraisal and evaluation of accidents and injuries is required to determine the costs of loss producing practices and conditions. This involves all of an organizations disciplines that concern themselves with a more efficient and cost effective organization. To come to know the cost of your safety program or how much is expended yearly for each employee on safety; to know what your safety costs are per man-hour or per ton-produced; to know what the health, medical and compensation costs are for any given incident are just a few of the important facts and figures that the safety management of a given organization needs to know to operate in the mining industry today.

Jan 1, 1984

By Andrew Hall

Many Latin American countries are facing a scarcity of water. As such, infrastructure decisions are quite different from those made in parts of the world that experience a positive water balance. In the latter case, the water treatment approach tends to be ?treat and discharge.? For Latin American regions facing the challenges that go with a negative water balance, the focus is on resource optimization and reuse. Historically, the water challenge has had a significant impact on economic development in Latin America, especially in sectors such as mining, where water usage is high. At the same time, countries such as Chile and Brazil are major development targets for mining and oil and gas operations. Given the water supply challenge, industry is increasingly turning to technologies and processes that maximize water recovery and reuse. With sulfide precipitation and ion exchange water treatment processes for example, it is possible to treat and recover more than 99 percent of water for reuse onsite. These technologies have been applied successfully in other regions of the world where water conservation practices are essential to economic survival.

Jan 1, 2012

By William Gleason

"Sometimes it’s the smallest things that make the biggest difference. In the world of mining, erosion can lead to small cracks, which can then lead to bigger problems that, over time, can eventually lead to a catastrophic event. However, when managed correctly, as in the case of the Manefey Slide at the Bingham Canyon Mine in Utah, the damage can be minimized.Numerous industry conferences, technical papers, studies and resources are dedicated to these issues each year, but what is sometimes overlooked is how the erosion of personal ethics can also have life-changing effects.At the 2019 SME Minnesota Conference, April 15-17 in Duluth, MN, two inmates serving their respective prison sentences at the U.S. Federal Prison Camp in Duluth spoke to the conference about how small cracks in their ethical foundations grew over time, eventually leading each man to his new address at the minimum-security facility.The men’s full names were not released and they were introduced as Jeff and Tony. Other than the matching green uniforms, both middle-aged men could have fit in with the rest of the crowd. They are well-educated and articulate whose career paths eroded thanks to greed and careless decisions.Tony, a licensed professional engineer, enjoyed a successful career working in contract oversight for the U.S. Department of Defense. Jeff is a former senior vice president of investments who ran a well-respected investment management team. Both spoke openly about the mistakes they made and emphasized that their crimes were not flagrant violations of the black and white rules but grew from ethical violations that live in the gray area between black and white, and right and wrong.Working in contract oversight for the U.S. Department of Defense (DOD), Tony said he was befriended by a wealthy man who was generous with his money. As Tony told it, a few meals with this man led to a few trips to casinos and eventually to gifts of money. The donor did not ask for anything in return, and at the time, Tony said he did not think that he was doing anything wrong. He admits now that the perception of a high-ranking officer in the DOD accepting gifts is not a good one, as it could be construed as the donor might have been trying to gain favor for future contracts; which is how it was presented in court by the prosecution team."

Jun 1, 2019

By Rodolfo V. de la Cruz

This paper describes the development of a modified Goodman Jack method for determining the mechanical properties of rock masses in situ. The modified method consists of the basic borehole loading device and a friction-strain-gauge measuring module. The friction gauges, located in the central portion of the jack, are impressed on opposite quadrants of the borehole walls and the remaining quadrants are loaded by the borehole jack with a uniaxial self-equilibrating pair of forces. The tangential strains generated at the borehole walls are thus measured concurrently with the loading. For ideal elastic materials, the tangential stresses at any point on the borehole walls due to jack loading can be obtained from closed-form analytical solutions utilizing the complex variable method. Complete stress-strain curves for the rock material can then be directly obtained from the tangential strain measurements and the calculated tangential stresses at those points. The continuous data are considerably more significant and reliable than averaged or point data obtainable by other current in situ measuring techniques. Moreover, the advantages inherent to the original Goodman Jack method are also obtainable in the modified method. The suitability of the new method was demonstrated by carrying out a number of laboratory measurements in large specimens of reinforced concrete, aluminum and granite blocks. The results of actual field measurements carried out in sandstone and granite quarries were found comparable with those obtained in the laboratory.

Jan 1, 1976