Search Documents

By J. Herhold, S. Plaum

The focus within the economical optimization of projects, which are conducted underground, shifts more and more towards the conduction of construction work underground. Underground operations can be defined in a wide range of various projects, from underground mining tasks to the construction of engineering structures. Within these projects the conduction of construction work cannot only be defined as absolutely necessary, but sometimes also as optimizing for underground processes (e. g. installation of workshops underground to support the mining processes). Even though the conduction of underground construction might cause positive outcomes concerning the productivity, it also tends to be challenging due to local (sub-surface) conditions and influences. To minimize the risk of failure and sudden events within in the conduction of construction work underground, the tool “work preparation” shall be used. Under the given constraints, such as local influences, expected construction work and set time frame, the conduction of the construction work will be planned in advance by consideration of the construction logistics as well as the selection of a fitted construction technique. PROBLEM DEFINITION Economic Challenges - Raw Material Extraction Enterprises in the construction, mining and raw material extraction industries are increasingly under the pressure to perform economically to sustain their position on the global market. Profitability, efficiency and productivity are the basic conditions to be an active participant on the global market as well as a business partner and contractor for mining and construction projects or projects related to the extraction of raw materials. The completion of large-scale as well as common construction projects above ground has been under the pressure to minimize costs and time whilst maximizing the potential outcome, in the meanings of quality and economic gain, for more than a decade now. Whereas the construction industry has to fight the competition on the market with efficient project outcomes, the mining industry has to find ways to perform efficiently to further conduct the extraction of decreasing raw material deposits. The ongoing exploitation of existing raw material deposits to satisfy the constantly increasing raw material demands world-wide, led to the predicament that economically mineable deposits have decreased dramatically. Even tough mineral deposits do still exist on a global level, near-surface deposits decrease rapidly. Therefore, the extraction of raw materials within mining operations will be relocated further away from the surface in greater depths. With the growing distance from the surface to the mineral deposit, the extraction costs will increase many times over. With that in mind, the extraction costs will increase whilst the economic efficiency will decrease. The extraction of certain deposits will no longer be profitable with the common approach. To further extract raw materials efficiently even in greater depth, companies have to change their practice in different ways. That leads to the fact, if the deposits are in the depths, where the extraction processes won´t be economically, other (support) processes have to be in order to guaranty an economical corporate process itself. This precept will divert the focus from the actual mining process to support processes, where potential for optimization still can be found, as shown in figure 1.

Jan 1, 2019

"A commercially available through-the-earth (TTE) communications system was evaluated at an active underground longwall mine in West Virginia. This TTE system uses electricfield (E-field) sensing to send text-based communications through two separate antenna arrays connected in parallel. Each antenna array is composed of interconnected, grounded metallic rods or other such structures. Two-way communication between subsurface locations was investigated in this study using various antenna configurations. This field study was conducted as a part of a larger multisite evaluation of available TTE systems in an effort to determine their operational sensitivities. IntroductionWireless, through-the-earth (TTE) communication technology is designed to achieve point-to-point communication through solid strata using very low frequency (VLF) and ultra-low frequency (ULF) electromagnetic waves. Using this approach, communications are established without the need for intermediary communications infrastructure. As a result, TTE systems have the potential to provide reliable, robust communications between surface and underground personnel. Exploration into the use of TTE technology for this purpose dates back to the 1920s (Jakosky and Zellers, 1924; Pittman, Church and McLendon, 1985), but U.S. permissibility requirements slowed the development of TTE equipment for widespread implementation (Durkin 1980; Pittman, Church and McLendon, 1985). One of the primary challenges in producing wireless TTE communications is the counteraction of signal attenuation when propagating through solid strata (Barkand, Damiano and Shumaker, 2006; Wadley, 1949). The long wavelengths of TTE transmissions make them well-suited for reducing the rate of attenuation. However, even when operating within the VLF to ULF range, the performance of TTE systems is still affected by geologic and anthropogenic factors (Geyer, 1973; Geyer and Keller, 1976; Geyer, Keller and Ohya, 1974; Jakosky and Zellers, 1924; Large, Ball and Farstad, 1973). Although commercially developed TTE systems have demonstrated the ability to communicate in a variety of conditions, their range and performance have been highly varied (Barkand, Damiano and Shumaker, 2006; Geyer and Keller, 1976; Geyer, Keller and Ohya, 1974; Ilsley, Freeman and Zellers, 1928; Jakosky and Zellers, 1924; Yenchek et al., 2012)."

Sep 1, 2016

By D. G. Feuerbacher

Maximizing production of oil from sandstone petroleum reservoirs is aided by use of non-damaging drilling and workover/completion fluids. Various tests, such as X-ray diffraction, scanning electron microsccpy, petrographic microscopy, porosity and permeability are conducted on core samples. Several fluids are selected, on the basis of these results, for return permeability tests. A report is then written giving the results of all tests, potential reservoir problems, and recommended practices for exploiting the reservoir.

Jan 1, 1983

In the estimation of recoverable resources, geostatistical techniques such as Multiple Indicator Kriging require a change of support correction to derive theoretical recoveries based on an assumed level of mining selectivity. The change of support models most widely used in practice entail model based generalized corrections either on a global or local basis. Examples include the affine and indirect lognormal methods. Change of support corrections derived empirically through short-scale conditional simulation realizations often show notable differences compared with theoretical corrections determined using model variogram parameters. The existing changes of support models are reviewed and an alternative method is proposed.

Jan 1, 1999

By P. C. O. Chukabarah

Many aerodynamic and thermodynamic properties, such as temperature, pressure, velocity and density vary widely, and in random spatial and temporal manner for a given underground mine environment. Such variabilities are seldom evaluated statistically, even though the relevant theories and principles for such an approach are both available and feasible. The main purpose of this paper was to introduce the new methodology of applying aerostatistics to the analysis of multiple fan system in mine aerology and/or ventilation. Pertinent data were obtained from a small multilevel coal mine. Results proved and confirmed that aerostatistical methodologies are computationally more efficient, grounded in solid engineering statistical theories, and can be used to analyze networked parameters in mine environmental engineering.

Jan 1, 1994

By D. M. Conner

An innovative patented process has been developed to convert high volume wastes--fly ash from coal-fired power plants, municipal solid waste (MSW) ash from incineration, solids from waste water treatment and paper mill sludge into a high value and environmentally benign product in the form of a lightweight aggregate. Lightweight Aggregate is widely used in the building construction industry in the United States, Europe and some Asian countries. This paper will present the development of the process, the process itself and details on the first commercial scale plant. The commercial plant is owned and operated by Wisconsin Electric Power (WEPCO).

Jan 1, 1997

By Michael J. Fiannaca

Disseminated epithermal gold metallization occurs within a breccia unit interpreted to be a submarine debris flow. Cold is associated with oxidized pyrite, fluorite, and jasperoidal silica. A minimum of 9 million tons of open-pittable mining reserves will be cyanide heap leached as run-of-mine ore at a rate of 1.0 million tons per year. Careful evaluation of the combined results of successive sampling projects has established the pit plan, mineable reserves, and process metallurgy of the operation. The sampling procedure utilized for a given test depended upon geological interpretation as well as the procedures, successes, and failures of previous tests. This paper summarizes the sampling and testing procedures of the development effort in light of the project goals and attendant problems in achieving them.

Jan 1, 1984

By C. Geier

Previous mine incidents show weaknesses in mine rescue preparedness from poor training in decision making, leadership and incident command center (ICC) protocols. Computer simulations offer a larger range of training opportunities for mine rescue teams focusing on exploration and communications. The mine rescue simulator developed by the Colorado School of Mines and Rite Solutions Inc. utilizes four computers for the instructor and team, with the instructor monitoring the team?s progress. As the team explores, it relays information back to the Fresh Air Base, which then reports to the ICC. This forces a three-step communication procedure, enhancing the team?s overall communication skills and developing ICC protocols. The simulator is decision-based, demanding team decisions be made quickly. Upon completion, teams commented positively. Generally, participants said that the simulator is useful for learning how to communicate and make decisions during mine rescue emergencies. This mine rescue simulator improves team training, providing effective communications practice with an easy setup and no production interruption.

Feb 1, 2014

By Ulises Deveze T.

The coal company Minerales Monclova, S.A. (MIMOSA), the owner of the Mimosa R Line, is a subsidiary company of Altos Hornos de Mexico, S.A., the largest steel plant in Mexico with an annual capacity of 2.5 million metric tons of steel ingots. The raw material's which are used in the steel plant are provided by the following companies: La Perla Minas de Fierro, S.A., iron ore; Cia. Minera de Guadalupe, S.A., Cia. Carbonera La Sauceda, S.A. Cia. Minera La Florida, S.A., and Minerales Monclova, S.A., which provide the coal used for coke, and altogether constitute the industrial group AHMSA. The coal property of Minerales Monclova, S.A. is located in the Sabinas coal area in the northwestern part of the Sabinas basin.

Jan 1, 1974

By R. L. Lewis

The White Pine Mine is the second largest active underground copper mine in the United States, covering an area of approximately 34 km2 in the Upper Peninsula of Michigan. A numerical flow model of the White Pine Mine was constructed to evaluate engineering controls that would reduce the rate of mine water discharge after closure. Of the passive controls evaluated, the placement of low-flow bulkheads within the mine workings was predicted to offer the greatest benefit, reducing the rate of discharge by as much as 35 percent.

Jan 1, 1996

By T. F. Deems

The nature, usage and comparatively rare occurrence of ball clay is described. The importance of these white firing plastic clays in ceramics, particularly in the production of industrial sanitary ware and tiles, is emphasized. The US deposits are briefly discussed. What is known about relevant deposits in Brazil, Argentina, Colombia and Venezuela (the four largest ceramic producers in South America) is also described. The ceramic plants have been sited near the centers of population rather than the plastic clay deposits. At present, extraction is probably concentrated on surface residual deposits and lenses which require minimum investment. Native plastic clays are used exclusively in the tile plants, but in sanitary ware, they are often used as extenders of imported ball clays.

Jan 1, 1997

By Douglas H. Bolton

In recent years, equipment manufacturers have been busy developing remote control systems to catch up with the sophistication and efficiency of continuous miners. Now the tables are turned, and manufacturers are undertaking the new challenge of upgrading, refining and equipping continuous miners to take full advantage of the capabilities made possible by modern, successful remote control systems. Because the operator can safely advance the miner farther without pulling out for roof bolting, continuous miners now need to be equipped with means of complying with correct face ventilation, dust suppression, methane detection, diffusion and improved lighting. Some of the exciting possibilities being developed to catch up with remote control include feedback controls using laser beams as datum points, coal sensing devices with feedback signals to show the operator what the machine is doing, show where it is relative to the coal seam, how hard it is working, and more sophisticated use of cyclic control. Mining machinery manufacturers have accepted the new challenges, and faster, safer mining procedures are already in sight.

Jan 1, 1975

By K. Oraee

Excessive emissions of methane from the coal seams can have a serious adverse effect on both safety and productivity of longwall coal faces. Mechanization of coal faces has increased production possibilities to the extent that normal ventilation systems may not be able to ventilate coal face areas in order to lower methane content in the air to within legal limits. Production increases may therefore be prohibited for this reason, especially in gassy seams. Methane drainage from the coal seam by means of long holes and before production starts can act as a useful remedial action. In this paper a two dimensional mathematical model has been produced. The model that is based on finite elements, simulates a methane drainage system where the resultant risk is linked to the coefficient of diffusion, coal permeability, holes pattern and the duration for which the seam is subject to drainage. It is concluded that methane drainage of this type can assist in achieving production increases in many coals seems, especially where high gas content is a virtue of the seam.

Jan 1, 2010

By K. D. Luxbacher, J. T. Davis

"A wind tunnel was designed to examine air flow, heat transfer and layering near an active fire at a working face. This tunnel simulates an active entry in an underground coal mine including an attached cross-cut of similar dimensions. A steel rectangular duct 1 ft. (0.305 m) tall, 3 ft. (0.914 m) wide and 10 ft. (3.05 m) long composes the main body of the tunnel and represents a mine entry. Air flow is generated by an exhausting centrifugal fan attached to one end of the crosscut. This fan was sized to supply air velocities based on Froude scaling. A 6 in. (15.25 cm) propane burner is used to simulate fires of various heat release rates at the working face. Thermocouples are used to map heat layering in the tunnel. Ports are installed for the introduction of tracer gases into and from sampling the system. Barometric, differential pressure, and temperature sensors are also included to monitor environmental conditions. Details about the design and testing of the system are presented including an overview of how the tunnel was scaled to accurately represent fire and flow phenomena. Finally, the proposed use of the tunnel for better understanding of mine fire phenomena and prevention is given. INTRODUCTION Fires in underground mines have been a concern since the dawn of mining. While technological advancements, regulations and best practices have improved both fire detection and firefighting techniques, mine fires continue to represent high risk events. From 2006 through 2015, fires accounted for 1.06% of fatalities in underground coal mines and 0.85 percent of fatalities in all underground mines in the United States (U.S. Department of Labor, 2006 to 2015). In addition to the risk of loss of life, mine fires can cause millions of dollars in equipment damages and lost production revenue. Extensive research has been conducted on how fires occur and spread in underground mines. In addition to testing conducted by government agencies such as the Mine Safety and Health Administration (MSHA) and the National Institute for Safety and Health (NIOSH) (e.g.(Liming, 2006), researchers like Verakis and Dalzell (Verakis, 1988) and Lowndes, et. al. (Lowndes, 2004) have furthered this field by studying ignitions and propagation of conveyor belt fires. While the studies of belt fires in mines are extensive, studies focused on fires at the working face are few in number. The particularly confined space and limited access to a working face, coupled with less robust, temporary ventilation controls create a unique environment that warrants special attention. Separate from studies on mine fires, the use of tracer gases to characterize flow patterns in normal mining ventilation is well established. In 1982, Timko and Thimons (Timko, 1982) outlined current and future applications of sulfur hexafluoride (SF6). However, little experimentation has been conducted to study specifically how tracer gases might be used to evaluate active mine fires and the fires’ effect on the surrounding mine environment (e.g.(Lindsay, 2014). In order to better understand the dynamics of smoke layering from a fire in an enclosed space, a small-scale apparatus was designed to map smoke layering and to examine other aspects of fire behavior at a working face. In addition to studying smoke flow around an active fire, experiments will be conducted using tracer gases in order to determine how they might be used to evaluate an underground fire."

Jan 1, 2017

By Mario E. Rossi

Often geometallurgical models are prepared at various project stages from very few data and are assumed to be representative of very large tonnages. These may include recovery models; crushing and grinding parameters and models; models of concentrate grades; models of acid consumption; etc. These models commonly do not carry a measure of uncertainty or variability, and are taken at face value at the time of design and planning. This paper proposes a proactive approach to modelling variability, providing uncertainty estimates and thus allowing for risk analysis and mitigation of geometallurgical models. The variability model is built up by understanding the limitations of the pillars of a geometallurgical model: data uncertainty; geologic model uncertainty; domain definition uncertainty; and parameter estimation uncertainty. Of these factors, typically domain definition is the most significant contributor to geometallurgical model variability. First, the fundamental supports for these models are briefly discussed, with domain definition emphasized. Second, two methods for uncertainty modelling are proposed. The first, more applicable to conceptual or early-stage projects, is a simpler and more expedient alternative that provides initial assessments of variability. This is intended to aid management in decision-making related to budgeting, including further sampling and testing. The second, a block-by-block approach that allows a detailed assessment of risk for specific designs and mine plans, thus providing further opportunities for mitigation. In the example provided, emphasis is placed in communicating this variability to both management and technical personnel in the form of “measured-indicated-inferred” indicators and also block-by-block confidence intervals.

Jun 25, 2023

By R. L. Ziegfeld

It has often seemed to me that people are too prone to turn to new and untried materials in an effort to solve their problems, without giving sufficient consideration to the old stand-bys, except as a last resort, It?s a little like middle-aged men who are swept off their feet by the fresh beauty of a young girl without first considering the many advantages that a more mature woman has to offer. Maybe it?s because, like the older woman, the older materials have to make a determined effort to keep themselves looking young and attractive. T at?s just about the situation with which the lead industry is laced. We have to make a determined effort to keep lead looking young and attractive to industry. However, there is one difference and it is important, Lead can not only be kept looking young, but it can, in fact, actually be kept young, This results from two things. First, industry and technology are constantly changing. For example, we have known for years that the density of lead makes it ideal to stop gamma rays, but it is only recently that atomic fission as a source of gamma radiation has become an important tool of industry, That makes old knowledge about lead useful in developing a new market for it.

Jan 1, 1958

By E. G. dos Santos, M. M. Veras, C. H. Sampaio, A. S. Young, R. S. Paranhos, C. O. Petter, A. C. Bastos

"The major challenges of the current mining are the energetic optimization, the lowest water consumption and minimizing environmental impact. One technique that eliminates much of the waste avoiding milling sterile, operating without water and to decrease the generation of waste at the end of the process, must be considered a major innovation. One of the most important developments in these past 10 years in the mining industry was expanding the use of high-tech sensors aimed at pre-concentration of ore. Among the mining areas where this type of technology is booming is the industrial minerals. The most common sensors are color sensors with Charge – Coupled Devices (CCD cameras) allowing through the RGB colorimetric system, the separation of minerals with different hues, and in many cases, a difference in brightness. More recently, the development of the use of dual energy X-ray transmission (DE-XRT) Dual Zone allowed the separation by atomic density of the mineral constituents of the rock. This paper presents a review of these two techniques (CCD and DE – XRT) as well some results showing the use of these two techniques for Earth Rare and Limestone. INTRODUCTION The mining industry is going through one of its biggest technological changes since the industrial revolution by the implementation of new technologies, according to Australian Mining Magazine (2015), whose theme emphasized one of the 10 greatest challenges that mining will face in the coming years. Optimization of the energy matrix in mining is focused on reducing water consumption and minimizing environmental impacts. The implementation of sensor technologies (Sensor-Based Sorting - SBS) allows elimination of mill tailings and permits the mill to operate with reduced use of water or totally eliminate this consumption (Young et al, 2016). According to Jönsson (2014) mining has undergone striking changes with the expansion of sensors of high technologies applied in the pre-concentration of mining ores. These techniques have contributed over the past 10 years in the recapture of mining areas with emphasis on the environment and/or operational optimizations. In line with the requirements of technological innovation, the mining industry is forced to make improvements in gravimetric processes ensuring better levels of Run of Mine ore feed in beneficiation plants. The implementation of automatic sorting, assisted by dual energy x-ray transmission (DE-XRT) sensor technology, or charged coupled device (CCD) image capture camera technology in the feed plant, allows for the selective sorting of individual particles into pre-concentrations (Veras et al, 2016)."

Jan 1, 2017

By Hongjie Yu, Mike Mooney

Transitions between geological/geotechnical soil units have a critical impact on the operation and performance of a tunnel boring machine (TBM). Geostatistics-based probabilistic modeling is used to quantify the uncertainty in soil transition locations. This paper presents two unique soft-ground tunneling case studies where the results from the geostatistics-based probabilistic modeling are compared to the TBM data and as-encountered ground conditions derived from the actual TBM data. The assessment enhances the confidence in using geostatistics to improve ground awareness for efficient tunnel construction, minimizing different site condition (DSC) claims, and improving decision-making on tunnel projects.

Dec 1, 2022

By W. J. McDonough

Rapid growth and acceptance of engineered materials have changed the way we live. We have come to expect improved performance at less cost. At the same time, our awareness of societal and environmental issues created by these materials during and after their lifetime has been heightened. As a result, material lifecycle analysis is receiving considerable attention. Material lifecycle analysis evaluates the cost/effective tradeoffs at each stage of a material's life: feedstock, fabrication, performance, recycle, and disposal. The U.S. Bureau of Mines investigates a material's lifecycle using technical cost models augmented with decision and impact analyses. Results of these studies are useful in gaining a better understanding of current material selections and illustrating the multifaceted issues associated with engineered materials in today's society.

Jan 1, 1992

By J. Mattern

Performance monitoring, operational practices and ongoing collection of geologic data in open pit slopes all provide valuable information for quantifying potential steepening of subsequent slopes. Mining at the Goldstrike open pit has been ongoing since the early 1980’s, with its share of slope instabilities. In areas where slopes have remained stable, consideration has been made for potential slope steepening of final walls. With the proper available equipment, steepening of bench face angles via pre-split blasting is not an uncommon method for steepening of inter-ramp slope angles. As an alternative at Goldstrike, the commonly used Modified Ritchie Criteria for empirical catch bench width has been adjusted resulting in quantified, rock specific formulas for bench width and rock fall berm placement. The result is an inter-ramp slope angle increase of 2 degrees on a 300m high slope, without the necessary purchases and procedural changes that would be required for pre-split drilling and blasting. The result has shown significant net benefits through reduction in mined waste tons and an increase in gold reserves. Location The Goldstrike open pit is located on the Carlin Trend gold belt in northeastern Nevada USA (Figure 1). The mine has produced over 43 million ounces (1.2M kg) of gold during the past 30 years. Engineering Geology Stratigraphy Figure 2 is a stratigraphic section of the rocks in the Goldstrike open pit. Quaternary alluvium and Miocene materials typically are poorly indurated stiff soils and are not present in all locations. Bedrock units consist of siltstones, mudstones, sandstones and cherts. From top down the major units exposed in the open pit are the Vinini Formation, the Rodeo Creek Unit, and the Popovich Formation. In general, rock mass strength increases with depth.

Jan 1, 2019