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The objective of this paper is, firstly, to summarize several field developments utilizing the art of hydraulic fracturing as it has been extended into various mining applications. Secondly, to summarize the understanding of the hydraulic fracturing processes; and lastly to discuss researchable areas and possible future applications. Hydraulic fracturing was developed as a method of stimulating production of oil from oil producing formations. The primary paper by Clark (1) in 1949, describes the process of placing a hydrostatic pressure of sufficient strength on the producing formation of an oil well that the rock apparently cracked, and then, on allowing the well to flow back, a higher rate of recovery of oil was enjoyed. The interpretation of the process mechanism was that the formation rock was cracked to a considerable distance from the well bore, increasing the drainage area; thus, the productivity of the well was measurably improved. Figure 1 is illustrative of this process. This development was of major significance to the oil producing community and considerable research and development ensued. Improvements in method, engineering development of equipment, and research to ascertain the optimum application of fracturing practice led to a highly sophisticated, but specialized technology. The Production Research Division, Continental Oil Company, vigorously pursued research in this area in the 1950's with a resulting number of process improve¬ments. The research group, published a significant number of technical papers on these various researches. One of the developments was the process aimed at controlled orientation of the fractures, either in the vertical (2) or horizontal (3) orientation.

Jan 1, 1969

By J. J. Bean

The development drilling program of the Copper Cities mine indicated that the molybdenum content of the ore would be about 0.011% MoS2' The molybdenum content of the Miami mine at the same time was about 0.025% MOS2' The Miami mill had a very successful molybdenum operation which used bleeder turbine steam from the Miami power plant for the steaming operation. The much lower grade of the Copper Cities ore, the absence of a source of low cost steam and the use of sodium aerofloat as the copper collector which Miami experience indicated did not respono readily to the steaming technique made very doubtful the success of a similar operation at Copper Cities. However, the relatively few pounds of copper that could be recovered from the low grade Copper Cities heads made very desirable the recovery of the molybdenwa,as a source of additional revenue. Accordingly, shortly after the Copper Cities mill began operation, a research program was instituted to develop a suitable method of molybdenum recovery. This program explored first, the successful steaming process then in use at Miami and as expected, found it unable to decompose the sodium aerofloat copper collector. The known chemical depressants were then tried without much encouragement. Finally the copper concentrate was dried, not roasted, to 2-3% mOisture and this along with sodium ferro-cyanide and cyanide resulted in sufficient copper depression that a final molybdenum concentrate containing 1.0% CU could be made. The bench scale testing was followed by pilot plant testing. Sixteen

Jan 1, 1972

By E. Watkins, S. J. Schatzel, V. Gangrade, K. M. Ajayi, Z. Khademian

Longwall-induced deformations could jeopardize the mechanical integrity of shale gas well casings positioned in the abutment pillar of a longwall mine. The in situ and induced fracture networks surrounding the gas well could provide pathways for gas flow into the mine creating safety concerns. Hence, this study by the National Institute for Occupational Safety and Health (NIOSH) develops a discrete fracture network (DFN) model to characterize the fractures in the overburden based on geomechanical analyses of mining-induced fracture apertures at a study site in southwestern Pennsylvania. The apertures from the geomechanical model are used to develop a stochastic DFN model of the site in fracture flow code (FFC). Multiple realizations of the stochastic DFN model that replicate potential fracture geometries are simulated, and the fracture permeability is compared with field measurements. A maximum field measurement of 5.03 × 10− 12 m2 (5080 mD) and 3.82 × 10− 13 m2 (386 mD) was estimated over the abutment pillar at the Sewickley and Uniontown horizon, respectively. The results show that the average permeabilities from the DFN model agree closely with the field measurements. In addition, the comparison of all the field measurements and 100 DFN realizations show the model is representative of field conditions. These findings provide critical information regarding fracture characteristics in the overburden, which will further be used to predict potential shale gas flow to the mine in the event of a casing breach for an unconventional gas well.

Jun 17, 2022

By C. Rodriguez, T. BoBo

Comminution, being the energy intensive part of a mining operation receives much scrutiny by cost controllers, CEO’s, investors and others as the mining industry goes “back to basics” to reverse the decline in productivity which occurred during the mining super cycle. Blasting is the first and lowest cost per ton stage in the comminution value chain. The basic principle that effective blast design can optimize fragmentation from the Run of Mine (ROM) ore muck pile to improve productivity through digging, loading and crushing to grinding and increase mine site profits has been well documented. Benefits of controlling fragmentation in the blast include reduced wear on equipment, faster loading, increased truck loads while detecting oversize rocks at the muck pile can reduce the frequency of a blocked primary crusher. A second basic principle is a measure of particle size distribution (PSD) at each unit operation in the comminution cycle allows engineers to manage blast design to produce fragmentation in the ROM ore most suitable to optimize downstream unit processes to improve mine site productivity and profits. Split-Online® systems have measured PSD of rocks on conveyors from the primary crusher to the SAG mill for over 20 years. Split-Engineering partnered with various mining companies to develop Split-ShovelCam® to automatically measure fragmentation from shovels and excavators working the ROM muck pile. This paper takes the reader “Back to Basics” by discussing the use of real time fragmentation analysis at the muck pile as an important parameter to optimize energy factors required for each blast. Case studies are given. INTRODUCTION The basics of mining are: • Explore for and find economic resources of valuable minerals • Mine rocks containing valuable minerals using blasting • Crush and grind rocks to liberate valuable minerals (comminution) • Recover valuable minerals for sale Comminution is an energy intensive process which accounts for a major proportion of mine site costs. Effective blasting can improve comminution and deliver significant reductions to mine site unit costs, (CEEC, 2016). Engineers, scientists, builders and even philosophers have long promoted the phrase “measure to manage”; the premise being “you can’t improve what you don’t measure”. Blast Engineers measure fragmentation in ROM ore for feedback to manage energy input in the design of blast patterns to optimize the ROM product size for downstream operations, whether they be for ROM Leach or feed into the primary crusher.

Jan 1, 2019

By William Lodding

That grinding may change a crystalline material both in a physical and in a chemical sense has been shown by a number of authors in recent years. Thus Mackenzie (1) and Bartha (2) reported the effects of careful grinding on muscovite, quartz, gypsum, dolomite, etc. Increase in specific surface produced by grinding implies increase in total energy of a system. Newly produced surfaces are chemically more reactive; dislocations may be introduced during grinding, and existing strain may be released by the same process, as shown by Holt et el. (3) All these changes are easily detected by thermal analysis, but it is not easy to separate the multiplicity of effects registered and to arrive at quantitative interpretations. This paper is an attempt to analyze by the use of thermal analysis some effects produced in grinding. In differential thermal analysis (DTA) one measures all thermal changes occurring in a substance during heating or cooling. Chemical changes, such as decompositions, synthesis, oxidation, reduction, etc., and physical changes such as phase transformations, changes in specific surface and in thermal conductivity, strain release, etc. By thermo gradmetric analysis (TGA) on the other hand only chemical changes involving weight loss or gain are recorded. Similarly gas evolution analysis (GEA) will register only reactions involving gas evolution, including water vapor, and oxidation-reduction. By performing two or all three of these thermal methods of thermal analysis simultaneously and on the same specimen one can separate the different effects registered and by difference evaluate their magnitude.

Jan 1, 1966

By C. T. Aimone-Martin

Time-domain reflectometry (TDR) laboratory experiments have been conducted using cylindrical salt cores from the Waste Isolation Pilot Project (WIPP). TDR has been used as an instrumentation technique to quantify the type and magnitude of rock mass deformation. Laboratory shear and tensile tests were conducted to calibrate measured deformation versus changes in reflected waveforms. Coaxial cables grouted within rock cores were crimped to produce localized reference defects. The evaluation of waveform characteristics produced during rock deformation experiments shows a good correlation of cable response to both shear and extension of the salt

Jan 1, 1994

By Michael J. Shulman

The DEAREX knowledge acquisition and engineering system is a teaching and exploration tool designed to facilitate the under- standing and development of expert systems by explorationists without the aid of a knowledge engineer and without recourse to expert system languages. To fulfill its objective, the DEAREX system considers the selection of exploration methods in desert areas. The system consists of three parts: 1. A tutorial which introduces the basic and selected advanced concepts of expert systems, 2. A sample program illustrating how an expert system works and can be used, and, most importantly, 3. A knowledge acqusition and engineering program which enables users to develop their own expert systems. The tutorial provides a brief and concise introduction to expert systems, a 10 rule exploration example which defines, explains and illustrates the basic concepts and design of expert systems, and a glossary of expert system terms including cross references. The sample program is a larger, self contained example of an expert system with some commentary illustrating addition- al expert system concepts and the role of the knowledge engineer in particularizing rules and ascertaining the knowledge base. Restricting itself to the selection of exploration methods in desert areas, the knowledge acquisition and engineering program questions the user and converts the answers into an expert system. Questions pertain to geology, infrastructure, availability of instrumentation, personnel, etc. Additional information may also included. In conclusion, some salient points concerning knowledge engineering toolkits, shells and knowledge acquisition capabilities such as contained in DEAREX are discussed.

Jan 1, 1992

Placing a detonating explosive inside a volume of rock is an efficient method of rock fragmentation. The explosion generates internal tensile stresses in the rock, and because rock is a brittle material, this brings about crack propagation and fragmentation far more efficiently than does application of explosive on the surface. To get the explosive inside, we drill a pattern of boreholes and charge the explosive into the holes. This is really the one and only purpose of making blastholes in mining: to give access for the explosive to the interior of the rock. No matter how big and expensive a drilling jumbo we stand up in front of a rock face, and no matter how many boreholes we let it drill, the rock does not fall apart by itself without blasting. It is the action of the explosive in the boreholes that does it. When we consider that we need a pound or two of explosive for every cubic yard of rock to be fragmented, and a pint of borehole volume for each pound of explosive, we see that the process of blasthole charging is an important element in the whole process of rock blasting.

Jan 1, 1975

By A. E. Ketler

Powerful, yet inexpensive, personal computers running Windows-95 operating systems provide powerful mine-wide monitoring capabilities when properly engineered. Long awaited conductivity over LAN, phone and Internet links provide new dimensions for sharing information throughout an operator's organization, in- deed around the world. On-line data analysis, archival data storage and historical trend viewing generate shared inputs to production, safety and maintenance personnel. Five years in development, Rel-Tek's new EZ-Trol/W-DX system was engineered around the pilfalls of a Windows environment. It now offers higher speeds, 3D animated graphics and long distance telemetry - all with better reliability than ever before possible. The ubiquitous DDS utility inherent in most Windows was discarded in favor of a lightning fast RAM format. Several ponderous interpretive programs were redesigned into a single compiled entity, thus avoiding the overhead from message conversion, handshaking and transfer. To make the system user friendly, a 'Wizard" utility helps operators set up and reconfigure their systems on site. In-mine data acquisition telemetry was also re- vamped, incorporating a unique noise avoidance scheme, dubbed the "DX" bus - enabling longer distances and higher reliability. 12- bit analog conversion provides the enhanced resolution needed for field scaling auto-cal sensors. By mid '96, eight EZ-TROLMI- DX systems were up and running, several for more than a year. Factory updating and assistance are possible over a phone or Internet link. Our factory testing of components routinely includes actual operation at 2400 BAUD over 14 miles of twisted pair wires.

Jan 1, 1997

By Ashis Bhattacherjee, Subrata Chatterjee, Michael T. Dewey, Christopher J. Bise

In order to continue the advancements made during the past two decades in the reduction of the severity of accidents and injuries in underground coal mining, closer attention will have to be paid to the increasing number of accidents resulting in disabling injuries and lost time. With the increased emphasis on safety training reflected in the Federal Mine Safety and Health Amendments Act of 1977 (Public Law 96-1641, and on MSHA's current focus on the application of Job Safety Analysis, it appears that the acquisition, evaluation, and application of accident and incident data will take on an even greater importance. To manage this large amount of information will require a significant commitment of time and attention on the part of mine training departments. A USBM-sponsored research project is currently being completed at Penn State which focuser on the development of a model training program for mining. The program is based on five distinct steps which represent the coupling of a needs assessment with the program implementation. The five steps are: 1) database analysis, 2) workplace observations, 3) identification of trainable problem areas, 4) a library of training resources, and 6) the implementation of the program. In each of these areas, the microcomputer has proven to be a valuable tool for collecting, analyzing, and presenting accident and incident information. This paper will detail the manner in which microcomputers have been fully integrated into the model training program. Examples of applications at existing mines will also be discussed.

Jan 1, 1992

By Robert E. Ennis

The somewhat misnomered "continuous" face section is in most mines today still far from perfect continuity. Achieving uninterrupted flow of coal from the mining machine to the outside has been a long sought for goal. Clearly, the largest problem to be solved in continuous mining today is one of increasing the cutting time of the miner. Full machine utilization can never be achieved with the new high capacity miners, as long as their performance is tied to that of the shuttle car. Figure No. I illustrates the point at which shuttle car haulage distance determines unit productivity rather than the productive capacity of the miner. Continuous mining is never realized. A recent development has proven, however, that truly continuous mining and haulage is possible. The Bell & Zoller Coal Company working with the Research and Development Department of Hewitt-Robins Inc. developed and perfected a new mining system which offers advantages in terms of increased productivity at reduced mining costs and enhances the safety of personnel at the face. This new system involves the use of two pieces of equipment that form a unbroken link, at all times, between the mining machine and the mine belt haulage system. These pieces are a Mobile Bridge Conveyor, and an extensible panel conveyor. The following areas of discussion will be covered during the review of this development. I. The design and operating features of the new system. 2. Its application in underground mining 3. The performance of the system to date 4. Operation and maintenance cost considerations 5. Safety features of the system

Jan 1, 1965

By M. R. Shahan, W. R. Reed

A laboratory apparatus (shield dust simulator) was designed and constructed to simulate the dust generated during the advance of longwall hydraulic roof supports, or shields. The objective of the study was to develop a tool that could be used to test the hypothesis that foam applied to a mine roof prior to a shield advance could be used to reduce the respirable dust generated during shield advances. This paper will outline the design parameters for the development of the system, as well as describe baseline testing of coal and limestone dust. Results show the average instantaneous respirable dust concentrations that occurred during simulated shield advance. Confidence intervals were calculated from the instantaneous respirable dust data to determine the repeatability of the data produced by the device. INTRODUCTION During longwall mining, miners can be exposed to respirable dust that is generated during the advance of hydraulic roof supports or shields. National Institute for Occupational Safety and Health (NIOSH) researchers have conducted numerous surveys of longwall mining operations, benchmarking the operating practices and dust control measures in use. It has been determined that the shields are responsible for 27% of the respirable dust that is generated on the longwall face [1]. The dust generated by the shield advances ranks second, next to the longwall shearer which is accountable for 43% of the respirable dust generated on the longwall face. The respirable dust generated during the advance of the shields can be a significant contributor to the respirable dust exposure of the mining personnel operating at the longwall face, especially since some of this dust is generated in the walkway. Control systems designed to reduce the dust levels generated during the shield advance have the potential to greatly reduce the respirable dust exposures of the personnel downwind of these activities. One control technology to decrease the dust generated by the shield advances would be to apply a layer of foam to the forward shield-roof interface prior to the shield advance [2]. The blanketed layer of foam would interact with the material located on the top of the shield during the advance, preventing a portion of that dust from becoming entrained in the mine air. This layer of foam would be applied using a foaming nozzle located on the longwall shearer body that would spray foam on the roof surface as the shearer passed. Substantial laboratory work has been completed to determine the feasibility of this type of foam application. NIOSH engineers have classified the various characteristics of foaming agents, using foam expansion ratio and drainage as important properties, as well as developed the mechanical systems required to apply the foam safely to the mine roof [2, 3]. The construction of an apparatus that could simulate the mechanical interaction between the dust-laden shield top and mine roof was necessary to adequately test the hypothesis that foam could be an appropriate control. A team of engineers designed and constructed a shield dust simulator system allowing for in-house testing prior to a full-scale field investigation.

Jan 1, 2019

By S. S. Peng

A well designed mining plan is one which minimizes the cost and the mining induced problems and maximizes the recovery of the coal reserve. In order to minimize the negative effects on surface structures caused by ground subsidence process due to underground mining activities, two kinds of practices are commonly employed by the mine operators. One is the support techniques which leaves an area of coal un-mined or partially mined beneath the structure to be supported. The other is the protection techniques which protect the structure when it is subsiding with ground taking advantage of the ground subsidence process (Luo et al., 1992). In designing the supporting techniques, the only currently available method in the U.S. is the one stated in the Pennsylvania Underground Coal Mining Rules (1985). However; The size of the support area designed by this method will be excessively large resulting in wasteful use of coal reserve when the overburden depth is more than 350 ft. A more scientific method is proposed in this paper for de-signing the support area. This method is based on a large amount of subsidence data collected throughout a number of major U.S. coal fields and the authors' experience with monitoring and protecting surface structures undermined by longwall panels. It considers the critical deformation in-dices that a structure can tolerate, and depth and height of underground extraction. The support area designed by this new method will not only assure the safety of the structure to be supported but also maximize the extraction of the coal reserve.

Jan 1, 1993

By J. W. Cooksley

Seismic methods provide an efficient and comprehensive approach to overburden studies pertinent to mining exploration and development, and to other mining and civil engineering problems such as rock mechanics, slope stability, and foundation engineering. For the purpose of defining geologic units and structural features, these methods are generally regarded as the most accurate, but most expensive, of the commonly-used geophysical exploration methods. Although the accuracy and cost of seismic work are generally affected adversely by rugged topography and complicated geologic conditions, it is in rough terrain and complex geology that seismic methods offer important advantages in overburden investigations. For example, to find the surface of rock underlying unconsolidated overburden at depths of approximately 200 feet, a 50-foot spacing of drill holes along the profile line would be required to yield a degree of resolution and accuracy similar to that obtained from a 50-foot spacing between seismic detectors along the same line. See Figure 1. In cases similar to that shown in Figure 1, a twelve-channel recording seismic system would be used. The main components of such a system would be: 1. detectors (commonly referred to as geophones) which convert the ground movement resulting from seismic waves into an electrical signal. 2. a multi-conductor cable which connects the seismic detectors to the amplifiers. 3. ampliiiers, amplify and filter the electrical signals . 4. oscillograph, records the amplified signal. 5. the blaster and firing line. A typical layout of the seismic spread and the components of the system Is shown in Figure 2.

Jan 1, 1968

By Robert A. Haney

During the last ten years, longwall mining systems have undergone many changes. Panel widths and lengths have increased. Longwall faces have become more automated. Average production from individual longwall panels has increased from 1,000 to 3,600 tons per shift. To control the dust generation resulting from the higher production, longwall dust control systems have integrated various dust control techniques. Systems designed to control dust generated at the crusher/stageloader, shearer, and supports are common to most longwall faces. A survey was made of the dust controls that are currently in place on all the longwalls in the U.S. This survey addressed the types of controls used to reduce dust generated at the crusher/stageloader, shearer and roof support movement. Additionally, information on face ventilation rates, cutting cycle and level of automation was obtained. The purpose of this paper is to review the dust control practices that have been implemented throughout the United States and to identify those controls that are being used on high production longwall faces. Additionally, a model is used to demonstrate how ventilation and automation affect occupational exposure. Automation of roof support movement can offer some of the greatest reductions in occupational dust exposures. While technically feasible, its full benefit has not been fully realized by the industry. Until technology to fully automate longwall mining systems becomes more reliable, future dust control systems must rely on increased ventilation, application of headgate dust collectors, improved shearer dust controls and improved shield dust suppression systems.

Jan 1, 1995

By Norman E. Lehman

INTRODUCTION The Washington Camp - Duquesne mining district is located on the east flank of the Patagonia Mountains, 98 kilometers south of Tucson and within 5 kilometers of the International border (Figure 1). Since the development of high-grade silver and copper ores by settlers in 1862, the Washington Camp - Duquesne district has yielded an estimated 450,000 metric tons of ore. The mined ores averaged 8% zinc, 2% copper, 3% lead and 124 grams of silver. REGIONAL GEOLOGY The Patagonia batholith, of Laramide age, crops out in the core of the Patagonia Mountains intruding Precambrian granite, Paleozoic sediments and Mesozoic igneous, volcanic and clastic rocks. This granodioritic batholith lies in a northwest-trending zone of Laramide plutonic rocks, which can be traced for a distance of 320 kilometers from the Nacozari district in Sonora, Mexico to the Silver Bell Mountains west of Tucson, Arizona. Several major porphyry copper systems occur within this plutonic belt including the Red Mountain deposit found at the northern end of the Patagonia Mountains. Data from more than 80 mineral deposits within the Patagonia Mountains show metal zoning symmetrical to the Patagonia granodiorite (Graybeal, 1975). Disseminated copper-molybdenum deposits occur within the batholith. Pyrometa-somatic, limestone replacement and vein deposits of copper, lead, zinc and silver occur in the wallrocks adjacent to the. granodiorite and epithermal manganese-silver deposits occur at the outer periphery of economic mineralization. GEOLOGY OF THE WASHINGTON CAMP - DUQUESNE DISTRICT Stratigraphy Nearly 900 meters of miogeosynclinal Permian and Pennsylvanian sediments are exposed in the district (Figure 2). In addition, 700 meters of older Paleozoic rocks crop out 6 kilometers north of the district. The Paleozoic rocks occur in fault contact with a sequence of Triassic-Jurassic pyroclastic and flow rocks, ranging in composition from latite to rhyolite.

Jan 1, 1977

By James M. Krese

The West Kentucky Division of Island Creek Coal Company, which is a wholly owned subsidiary of Occidental Petroleum Corporation, operates the new Hamilton Mine. It is located six miles West of Morganfield, Kentucky, in the Northwest section of Union County, adjacent to the Ohio River in Lock 50. On July 15, 1968, a unique new coal conveying system was put in operation. This system consists of eight conveyor units carrying coal from the bottom of the mine slope ultimately to barges on the Ohio River. It is over two miles in length and has a total of 3175 connected horsepower. The river loading conveyor is the longest 72" wide conveyor in operation in this country.

Jan 1, 1969

By V. N. Kazakidis

With increased levels of automation, capitalization, and empowerment of citizens, the traditional axis of labour versus capital or national government versus capital, upon which the allocation of benefits from a mining project was traditionally based, has shifted primarily to a capital versus community axis. In light of this paradigm shift, it is critical for the sustainability of mining that economic indicators be considered at the pre-feasibility, feasibility, and permitting stages of a project. Such indicators should emphasize the ?ripple effect? of the economic impact of a capital-intensive mining investment on a region due to outsourcing, as well as the diversified spin-off opportunities and the technological advances that can be exploited by local communities.

Jan 1, 2003

By Barry J. Hansen

In the past six years, the Hanna Mining Company has increased its pellet producing capabilities greatly by the construction and expansion of six pelletizing plants in North America. At the present time Hanna managed pelletizers have a nominal capacity of 18 million long tons per year. This capability makes Hanna one of the world's largest pellet producers. To create and maintain such an operation has required the skill and dedication of many people in all aspects of the company's activities, in the various fields of exploration, operations and research. The Research and Development Group consists of the staffs of two laboratories situated on the Mesabi Range in northern Minnesota. These laboratories are well equipped to carry out work in the fields of beneficiation and extractive metallurgy especially iron ore treatment. Facilities exist for the batch and semi- continuous investigation of the unit operations common to iron ore beneficiation and pelletizing. The R and D Division is divided into groups according to specialized areas of interest. Presented in this paper today are some aspects of the activities of the Pelletizing Group of the Research & Development Organization.

Jan 1, 1969

By Morton Handelman

The extraction of aluminum oxide_ from its ore is the initial step in the commerical production of metallic aluminum. This is most commonly done by the Bayer Process in which a caustic solution is used to dissolve hydrated alumina from the insoluable materials with which it is associate in bauxite. At the two-thousand ton per day Sherwin Alumina Plant of Reynolds Metals Company, the extraction residue from Caribbean ores is removed from the main pro¬cess stream as the underflow of a continuous clarifier-thickener operation. This sludge, prior to its ultimate r4jection from the process, is washed in a nine-step continuous countercurrent decantation system to recover physically-entrained mother liquor. Control of alumina production costs requires the optimum recovery of solubles from this residue which is generated at the same rate as the finished product. The equipment, operating techniques, controls and process variables which affect the efficiency of this soda recovery from Bayer Process red mud will be discussed.

Jan 1, 1959