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By R. F. Kehrman

Voice Frequency (VF) electromagnetic trapped miner location devices were tested for reliability and effectiveness in 93 coal mines. Tests included uplink pulsed CW, downlink pulsed OW and downlink voice evaluations. Frequencies were 630, 1050, 1950 and 3030 Hertz. Overburden depths varied from 70 feet to 1550 feet. Successful communications were established at 91 of the 93 mines. Data indicate the transmitters and receivers will operate in practically all coal mine environments. Reliability and accuracy as location devices appear to depend on noise, depth and presence of metallic objects which distort the magnetic field. In addition, theoretical models appear to define best case situations in terms of noise and conductivity. Minor hardware problems were encountered, mostly involving battery contacts, switches and antenna cables on the receivers. No hardware problems occurred with the transmitters.

Jan 1, 1978

THE area dealt with in this paper is included within a radius of about 3 miles of the Poimena township. Several thousand tons of tin have been won from this field, and probably £200,000 spent in exploiting it.PREVIOUS LITERATUREThe field has been reported on by Government geologists on four occasions and several ,articles on it have appeared in the mining journals. The work done by Government geologists is summarized below:-"Report on the Blue Tier Tin Mining District and its Tin Deposits", 1886.Speaking of the tin-ore occurrences, this paper states:-"In the primary granite the lodes of tin ore occur, also dykes and belts of more recently obtruded porphyries. The really valuable metalliferous deposits may be classified as follows :-1. Lodes (of which the Lottah mine is typical).2. Dykes- (a) Indurated or hard (as shown by the formations at the Anchor and Cream Creek mines). (b) Soft (eg Hayley's Lease).

Jan 1, 1912

By D. H. Trollope

In engineering in general, close agreement between theoretical predictions and structural performance is rare—this is particularly true in rock slopes. Since the complexity of natural arrangements makes exact theoretical solutions of associated structural problems almost impossible, the role of theory should be that of developing guides or markers to which observations and experience can be related. The author in this paper has outlined the results of a theoretical study of highly idealized models which represent both granular materials and jointed rock. Some important practical considerations result—especially in regard to horizontal stresses—when theory is compared with full-scale experience. In the field of engineering activity, specific examples of close agreement between theoretical prediction and structural performance are rare. Particularly is this so for the case of rock slopes, where, owing to the complexity of the natural arrangements, it is quixotic to expect exact theoretical solutions to the associated structural problems. The role of theory is rather that of developing signposts or guide rails to which observations and experience can be related. It is with this in mind that the present paper has been prepared; the author's aim has been to set out briefly the results of a theoretical study of highly idealized models which represent both granular materials and jointed rock. Despite the idealization of the problem, it will be seen that the theoretical conclusions are in accord with full-scale experience, particularly as far as horizontal stresses are concerned, and they point to some important practical considerations. CLASSIFICATION OF ROCK SLOPES At the risk of over-simplification, an attempt has been made to classify the problem of rock slopes into three broad categories with respect to internal stress systems. These are illustrated in Fig. 1. It is tacitly assumed in this classification that the strength of individual particles is very much greater than the interparticle strength whether the particles are the crystals of an igneous rock (Case I) or the blocks of Cases 2 and 3. The Homogeneous Monolith: This case is representative of uniform unjointed rock. Under relatively low stress conditions the internal stress system may approximate to that of an elastic body as given by Terzaghi.' It is more usual, however, for overall stability, to consider the material as a rigid plastic which yields in shear when S =C + c tan 4> where S is the shear yield stress, o is the normal stress on the surface of failure, and C and d are empirical constants according to the Mohr-Coulomb criterion of failure. Sokolovsky has recently developed, for the first time, a series of mathematical solutions to problems involvinga C, mass subject to self-weight. He demonstrates that for such a case a semi-arch (Fig. 2) is stable. A corollary of this argument is that for a true C, d material a curved overhanging slope is possible and such an observation may well aid field identification of these materials. The shape of the curved slope face is however directly dependent on the C-value, and from the long-term point of view this is a most difficult value to establish with any degree of confidence. It is customary to measure C and 0 in some form of shear test—usually a triaxial compression test—on core specimens sampled from the rock, and as far as the author is aware the present case is the only one in which, as far as overall stability is concerned, such tests are

Jan 1, 1961

By Paul M. Godlewski, Joseph P. Gildner, David S. McAllister

With construction underway on the 22.5 km (14 mile) Initial Segment of the Link Light Rail transit system in Seattle (including the one-mile EPB-driven running tunnels and mined station at Beacon Hill), the Sound Transit Board on May 20, 2004 voted on selection of a preferred route for an approximately eight-mile extension northwards from the central business district to Northgate, and authorized immediate start of advanced conceptual/preliminary engineering and geotechnical exploration programs scheduled to be completed in Spring 2005. The extension includes approximately914 m (30,000) route-feet of bored running tunnels, a mined station with platform level approximately 60 m (200 ft) below grade, three (possibly four) cut-and-cover stations and a cut-and-cover cross-over structure, as well as an aerial terminal station at Northgate and other line-section below-grade and aerial structures. All tunneling will be in glacial soils.

Jan 1, 2005

By Ronald W. Stingelin

This study undertook the development and implementation of a methodology for estimating the impact of coal seam interaction on the eastern bituminous underground reserve base as published in USBM Information Circular 8655. The effects of previous mining in multiple coal seam areas on currently mined and reserve seams are predicted as a percentage coal loss by an engineering assessment model called the Coal Loss Calculation Model. The model utilizes twelve input variables easily derivable from mine maps or other existing data sources and calculates the effects of subsidence and high-stress due to remnant pillars in the previously mined seam. Extensive literature review resulted in the identification, definition, and quantification of the critical variables of seam interaction. Export opinion surveys were made of mining experts, MESA mine inspectors, and coal mine operators. Statistical analysis was used to establish the redundancy of the critical variables and to develop a total coal loss prediction algorithm. A regional analysis resulted in the production of a series of thematic maps on coal characteristics and distribution. A derivative map showing the areas of commonality within the eastern bituminous coal region served as the basis for implementation of the coal loss calculation model. The model was developed and tested using data from four coal mines in western Pennsylvania and southern West Virginia.

Jan 1, 1976

By David A. Andrews

Coal occurs at many scattered localities in Arizona, California, Idaho, Nevada, and Oregon, but in most of the known occurrences thick coal beds are of small extent and the coal generally contains a high percentage of impurities. The coal beds occur at many different horizons in strata of Cretaceous and Tertiary age. Bituminous coal has been found in several areas, the most extensive of which is the Eden Ridge field of Oregon. Lignite also occurs in many places, but the only extensive deposit is in the Goose Creek field of Idaho, Nevada, and "Utah. The coal reserves of the region are largely of subbituminous rank; most of the subbituminous coal is in the Black Mesa field of northeastern Arizona and the Coos Bay field of Oregon. The Black Mesa field contains more than 80 percent of the coal reserves of all ranks but is remote from both transportation facilities and centers of consumption. Substantial reserves ill the Coos Bay field are favorably situated with respect to transportation and markets. ARIZONA Subbituminous coal occurs in the Black Mesa, Pinedale, and Gallup coal fields in Apache, Navajo, and Coconino Counties, Ariz. (fig. 1). Bituminous coal occurs in the Deer Creek field in Pinal and Graham Counties and in a small area in Apache County at the north-east corner of the State. All the coal beds are in strata of Cretaceous age. The coal in the Gallup field and at the northeast corner of the State lies in the Western edge of the San Juan structural basin. "Vest and south of this basin the coal-bearing strata have been removed by erosion except in high mesas.

Jan 1, 1947

A homely simile will serve to epitomise an interpretation of the rock structures and associated phenomena of the block of country under review, as it appears to the writer.Disregarding the many thousands of feet of overburden that have been eroded away during the ages, the present denuded surface and rock systems below may be pictured as a slab of some titanie ribbon cake that has suffered much damage from rough handling and exposure, yet retaining much of the original symmetry of its superimposed layers of variegated colour and texture.Lateral pressure has crumpled the cake into a series of irregular corrugations and, in parts, has caused some of the layers to crush and slide over their neighbours.Following upon this squeeze, the cake has been severed into segments and rhomboidal slabs by vertical cuts, and these portions have been severely jostled one against its neighbour, crushing the faces of contact and dragging the contiguous layers in the direction of movement.The variegated icing of the cake is represented by intercalated sills of amphibolite, pegmatite, and aplite, and the body of the cake by highly altered sedimentary rocks.The icing has been assailed by the rats of erosion with such effect that only residuals of the original structures remain. The body of the cake has suffered successive waves of igneous invasion in the order of lode pegmatite, followed by zine, iron,copper, and finally by silver-lead. These successive invaders found difficult access, along certain of the vertical cuts, to the more succulent layers of the cake, where, gorging to repletion, many were imprisoned and entombed for the future service of mankind.

Jan 1, 1927

The Bureau of Mines is operated to assist in promoting economic development through increased efficiency in the mining, preparation, treatment, and utilization of mineral substances; to aid in conserving mineral resources through preventing waste; and to help the mining industry improve health conditions and increase safety. Accomplishment of those ends is sought through investigation of scientific, technologic, and economic problems of the, mineral industries and dissemination of resulting information. Building materials of mineral origin constitute an important product of mining, and the Bureau makes studies of these in the various fields mentioned. The following commodities come within this classification: Asbestos, anhydrite, asphalt, cement, clay and clay products, diatomite, dolomite, glass and mineral wool, granite, greenstone, gypsum, lightweight building materials, lime, limestone, magnesite, marble, sand, sand and gravel, sandstone, sand-lime brick, slate, soapstone, and trap rock.

Jan 1, 1937

By David Conover

Technological advancements in electronic sensors and mine-wide monitoring systems have improved remote monitoring and analysis of underground mining information. The effective use of . these systems for ground control applications, however, remains a challenge facing the mining industry. The U.S. Department of Interior, Bureau of Mines is conducting research, utilizing real-time acquisition of rock mechanics data, to provide mine operators the means to rapidly identify and manage potentially hazardous ground conditions. The Bureau has installed a remote monitoring network in a Colorado coal mine to record Pressures from instruments installed in the roof and pi1lars of gateroads and from transducers on shield-legs along the face. The field data are being monitored at the Denver Research Center, 150 mi from the mine. A computer at the Center analyzes the field data and generates graphic displays, which permit detailed examination of mine-wide ground conditions in real-time. For the first time, Bureau researchers are able to perform real-time monitoring and analysis of rock mechanics data while mining is in progress. The data collection and display capabilities of the system were effectively used to identify and evaluate face stability problems at the mine.

Jan 1, 1990

By Steven K. Ruggieri

This report describes the operation and maintenance of the Mobile Inert Gas Generator for use in the Remote Sealing System for fighting underground coal mine fires. Seals are emplaced in mine passageways between the fire zone and the rest of the mine isolating the fire zone from the mine. The seals consist of fly ash that has been pneumatically conveyed via inert gas through a borehole connecting the surface and the passageway, Inert gas is used as the fly ash seal transport medium (instead of fresh air) since the introduction of large volumes of fresh air in the vicinity of the fire zone would be undesirable. The inert gas generation equipment is mounted on two flatbed trailers, the "hot" trailer and the "cold" trailer. The hot trailer contains the combustion and cooling equipment. The cold trailer contains the moisture removal and compression equipment necessary to convey the fly ash. The system is self-sufficient and requires only fuel and fly ash deliveries. The Inert Gas Generator has been thoroughly performance tested and has been operated in the field for approximately 200 hr. The system was employed in the demonstration of the entire Remote Mine Sealing System at the Jenney Mine in the Fall of 1978. The system is currently available for fighting any future underground coal mine fires.

Jan 1, 1980

By K. Goshtasbi

In this paper a genetic algorithm is used in a heavily jointed rock mass in order to investigate the critical circular slip surface and modification of slope surface. This method was applied to the southern wall of the 6th Golbini Jajarm bauxite mine. The mine is the largest bauxite deposit in Iran, located to the northeast of the town of Jajarm in the Khorasan province. Estimated reserve of bauxite in this deposit is about 160 million tonnes. Field and laboratory investigations were conducted in order to determine rock mass behaviour. A genetic algorithm code that uses the Simplified Bishop method as an objective function was developed for findingt he safety factor of circular slip surfaces. Sensitivity analysis was applied to determine the optimum values of the genetic algorithm variables, such as population size, selection method, crossover and mutation rates. After finding the critical circular slip surface, slope modification is carried out by removing unstable sections from marked critical slip surfaces, and this process is repeated until the last unsafe section is removed. Based on this code, modification occurred during 7 steps, by reaching a safety factor of 1.3 in the last step. Finally, the modified slope angle of the southern wall of the 6th Golbini Jajarm bauxite mine was determined to be 48.44 degrees. Keywords: Genetic algorithm, slope modification, circular slips surface, 6th Golbini Jajarm bauxite mine .

Jan 1, 2008

By B. Simser

At Brunswick Mine, an increase in the number of seismically-related falls of ground and in particular rockbursts occurred during 1999. This was due to the ever-increasing stress levels in the remaining ore reserves, mining in difficult highly stressed areas and in particular troublesome geological features. In conjunction with the Noranda Technology Centre, development of rockburst support systems started at the Brunswick Mine in 1996 and efforts were accelerated in 1999. A support package consisting of #6 gauge chain link mesh, #0 gauge heavy mesh straps, and a 1 m by 1 m pattern of modified conebolts was developed. The conebolts were modified to enable mixing of the resin anchoring. Two major rockbursts occurred during an intense seismic episode at the Brunswick Mine from October 13th to 17th , 2000.The area was evacuated approximately four hours before the first burst hit, and remained closed during the seismic ?flurry??. The first damaging activity occurred around midnight on Friday the 13th, and a second damaging episode occurred on the 17th that included a local Richter Magnitude 2.7 event. The second rockburst had dimensions of approximately 5 m by 5 m by 20 m or 2150 tonnes of massive sulphide material (density 4300 kg/m3). The first failure area was more extensive, caving approximately six metres of an intersection back with the lateral extent not safely measurable. This paper briefly describes the mining conditions that led to the bursting, the seismic response of the region, the mechanisms thought to have caused the bursts, and a yielding support system which had been partially installed before the burst.

Jan 1, 2002

By E. H. Burroughs

This bulletin is the fifth in the series of petroleum bibliographies publis:\:l.ed by the Bure.au of Mines, Bulletins 149, 165, 180, and 189 being compilations for the years 1915, 1916, 1917, and 1918, respectively. In this bulletin the same general plan has been followed in arranging the references, but a few changes and additions have been made in the classification.

Jan 1, 1923

By Robert L. Lappi

Volume I of this report described the demonstration of cross-ridge mountaintop coal mining. This document, Volume II, is intended for use as a supporting document to Volume I. This report describes the MATHMINE Mine Simulation System, a modularized software system used to support the demonstration of cross-ridge Mountaintop coal mining. The MATHMINE Mine Simulation System was used to generate mine plans for coal extraction at lowest cost. The functional details, data requirements and output of the software system are detailed here. The computer program was written in FORTRAN. One module which generates resource location data required the use of SAS?.

Jan 1, 1984

By Raymond P. Miller

This two volume report addresses slope stability of surface mine spoils within the Interior Coal Province. Sixteen (16) mines were visited, pertinent data and samples collected, and reported spoil instabilities back-analyzed. Laboratory test results are compared to back-analyzed material properties. Available methods of slope stability analysis are reviewed and evaluated with respect to application to mine spoil stability evaluation and prediction. Correlation and tentative relationships among spoil material properties, highwall conditions, mining equipment and procedures and empirical observations are presented. Slope stability sensitivity plots illustrate the relative significance of various input parameters on stability. Slope stability input parameters are correlated with site and mining conditions to identify the primary factors controlling spoil stability. Investigative methods, spoil stability enhancement techniques, spoil stability prediction procedures and future study areas are discussed. Appendices include a glossary of terms, annotated bibliography, details of mine visits, and detailed laboratory test procedures and results.

Jan 1, 1979

VOLUME I Volume I of this three-volume report is the result of development of a comprehensive, coordinated approach to site data-acquisition activities to produce key plans and reports during the evaluation and development of a surface coal mine. A logic diagram illustrates activities in the planning and decision-making process from exploration through post-mining monitoring. The report briefly discusses major elements, other than the site environment, which influence development of mining and reclamation plans and refers to other readily available literature for details outside the scope of this study. The essence of the rationale is shown to be the 1 employment of necessary skills at the proper time to evaluate specific data ' requirements and integrate them into a cost-effective program to produce initial and major feasibility reports, mining, and reclamation plans, and the environmental impact assessment.

Jan 1, 1976

This paper presents the near-field rock damage owing to production blasting in limestone quarry in the western region of Japan. The study's purpose is to learn the mechanism of crack development due to blast vibration. In this study, blast vibration's magnitude was expressed with peak particle velocity (PPV) which was obtained based on seismographs recorded database. In attempt to pursue a research's purpose of this study, there were two considerable interests: near-field blast vibration propagation and prediction, and crack observed and prediction. Furthermore, with regards to considerable interest of the study, there were three essential aspects which were challenged, such as: monitoring and interpretation of seismic wave propagation in a rock mass near large explosive charge of production blast scale, measurement of blast rock damage in adjacent to blasthole, and determine critical value of PPV which may produce significant rock damage. In order to determine precision critical PPV, understanding correlation between rock damage with vibration level is firstly important to be done. This paper also discusses how to measure, detect and quantify near-field blast vibration and blast rock damage in adjacent to blasthole.

Dec 6, 2010

By Bobby B. Gillenwater

This report presents recommended guidelines and regulatory changes applicable to electrical installations in underground oil shale mines. These recommendations are based on information gathered from oil shale operators, government agencies, and other knowledgeable sources familiar with existing plans for mining systems and electrical installations, and on present understanding of the problems and hazards associated with oil shale mining. Additional discussions of specific electrical problems related to oil shale mining are also presented. These specific problems include: ? Ground fault current levels ? Permissible electric wheel motors ? Permissible batteries and electric starting systems ? Intrinsically safe instrumentation and applicability of existing test standards.

Jan 1, 1983

By M. Jaffe

The data developed in this study establishes the technical and economic feasibility as well as the improved health and safety characteristics of a novel mining concept. The mining concept is a modified longwall technique using prestressed tendons for roof control, longhole blasting for fragmentation, and remote mucking. The technical feasibility was found to be dependent on the state of the art, while economic feasibility was found to be dependent on particular minerals and on supply and demand. Since these two conditions are not necessarily coincident in time the data is presented in the report in a manner that enables the mining engineer to perform a rapid preliminary technical and economic analyses for a specific property.

Jan 1, 1977

By Samer Sadek, Brian Hagan

We are thrilled to welcome you to the 2025 Rapid Excavation and Tunneling Conference (RETC), which will be held in Dallas, TX. This year’s conference will showcase the continued trend of strong industry interest, as there will be a record setting 115 papers being presented over the course of three days. The set of papers compiled in this book captures the latest and greatest information on a broad array of topics within our fascinating tunneling industry. We hope that the compilation of selected papers in this book will provide a comprehensive recap of the conference while also providing a source of future reference for contractors, engineers, and anyone in general who is a student of our beloved and unique industry. Since its inception in 1972, RETC has been the preeminent tunneling forum to promote ideas, tell stories, share lessons learned, and promote new technologies. RETC prides itself on its focus towards highlighting real-world experiences and practical ideas, with the intent to help the entire industry learn from one another and grow. The need for us all to stay sharp and remain on the cutting edge of technology has never been stronger – the technology and ideas that have been applied in aerospace are now attempting to mix with tunneling, and the advancement of AI continues to permeate all industries. However, no amount of technology or AI can fully replace the human element, and in our tunneling industry, the human element is key and is what sets us apart. In tunneling, every project is different, because the ground is always different. We can only take what the ground will give us, and we must rely on our past experiences to get through present day challenges. Most importantly, we must rely on each other. This is the heart of what RETC is all about. For those of you attending this conference, we encourage you to attend as many sessions as possible and engage with your colleagues to discuss during the breaks in between sessions. This sharing of ideas is what keeps us connected and helps to expand our industry. Please also try to engage with the scholarship students and the newcomers who will be in attendance, as it is the new ideas and fresh energy from the next generation that will continue to make our industry thrive into the future. The program chairs thank and greatly appreciate the efforts made by our session chairs, co-chairs, authors, the members of the RETC Executive Committee, and most importantly the SME staff towards making this RETC possible.

Oct 1, 2025