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By Patricia J. Leonard - Mayer

A Bureau of Mines surface resistivity method has been used to determine the joint strike and coefficient of anisotropy of jointed , nearsurface formations at five study areas . The field studies demonstrate the use of rotated , or azimuthal , Wenner-Lee arrays for determining the strike of predominant joint sets . The results of the field studies include the following : in a formation having a predominant , vertical joint set , the maximum value of the apparent resistivity ( pa ) occurs in the same direction ( azimuth ) as the joint strike ; the polar coordinate graph of pa for such a formation is approximately elliptical ; the coefficient of anisotropy ( ^ ) can be calculated from the field data , and values of λ for jointed formations are in the same range of values reported for layered formations ; values of λ are higher at mined sites than at unmined sites . The azimuthal resistivity method and horizontal profiling were used at a site in Pennsylvania to delineate a zone of intensely jointed and fractured bedrock that provided a flow path from a surface stream to a mine . Analysis of the data has been based on a simple model of a jointed formation having a single joint set ; the success achieved to date indicates the need for a more complex model and additional field data .

Jan 1, 1983

By J. William Ganser

This paper is one of a series being prepared by the U. S. Bureau of Mines describing mining and milling methods and costs at cement-plant quarries throughout the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs might in many instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically palled to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance of Fred Burkett, civil engineer, and F. O. Londrey, chief clerk, of the Trinity Portland Cement Co., for assistance in preparation of this paper, "The Geology of Dallas County. 1918," Bulletin 1818, Texas Geological Survey, Austin, Tex., by E. W. Shuler, was also freely consulted.

Jan 1, 1931

By O. Craciun, C. A. Bridges, M. Cai, J. Sugawara

There are a number of methods that can be adopted for predicting the ultimate lateral resistance of a free-head rigid pile, from the conventional Brinch Hansen and Broms solutions to three-dimensional finite element analyses. Often these methods give rise to significantly different pile ultimate lateral capacities which could lead to either unsafe or too conservative designs. It is also well known that finding a rigorous and practical solution is challenging due to the complex three dimensional and nonlinear soil-structure interaction. This paper reviews some of the most common methods and produces results of pile ultimate lateral capacities embedded in cohesive or cohesionless soils. Subsequently, a finite element analysis is performed using PLAXIS 3D modelling under the same design conditions. Based on comparison of results, limitations and advantages are highlighted, and the most suitable method is proposed from a practical point of view.

Nov 1, 2022

By Harold J. Schock

This paper describes an experimental method for the monitoring of diesel-generated exhaust gas pollutants in a dead-ended drift for the purpose of assessing the effect of control approaches. Experiments were conducted to determine the relative merits of these ventilation configurations: no auxiliary ventilation, induction ventilation at the entrance to the drift, and ventilation of the dead-ended drift with positive displacement tubing. The drift used in this experimental work was approximately 105 ft. (32.0 mf long and slightly downsloping, with an average height and width of 8 ft. (2.4 m) and 28 ft. (8.5 m1 , respectively. The data were gathered for assessing these ventilation methods and for gathering data to support a computer model of the dispersion and mixing processes. For this drift, it was found that ventilation with positive displacement tubing provided the best removal of diesel-generated pollutants. Induction ventilation appeared to be the least effective of the three methods examined. A comparison was also made between personal monitoring and area monitoring. Results of this analysis showed that in regions of high concentration gradients, it was not possible to get good agreement between point sampling and personal monitoring. In well-mixed areas, good agreement between the two methods of monitoring was obtained.

Jan 1, 1980

[Andrew Allen Glenwood Springs, Colorado C. S. Allen 211 Utah Oil Building, 10 West Broadway, Salt Lake City 1, Utah Earl W. Allen 257 Rio Grande Street, Salt Lake City, Utah Louis B. Allen 411 Walker Bank Building, Salt Lake City, Utah Thomas Allen State Coal Mine Inspector of Colorado, Argonaut Hotel, Denver, Colorado J. B. Ambler P. O. Box 591, Denver, Colorado Nephi W. Anderson Dragerton, Utah F. F. Argust 270 High Street, Pueblo, Colorado E. K. Arnston : 4601 West 26th Avenue, Denver 12, Colorado Abel Audin Somerset, Colorado Clement Audin, Jr Paonia, Colorado Ralph Andin P. 0. Box 285, Somerset, Colorado ]

Jan 1, 1955

The National Mining Association’s (NMA)MINExpo International ’96 is shaping up to be the organization’s largest. About 30,000 mining industry business and technical professionals are expected to descend on Las Vegas, NV Sept. 9-12 to take part in the 25 technical sessions and visit the more than 900 exhibitors who will be showing off their products and services. MINExpo will be the largest mining equipment and services exposition in the United States this year. Exhibits at MINExpo will fill the Las Vegas Convention Center, parking lots and part of the Hilton Center, located next door to the convention center. NMA estimates that this year’s show will cover more than 46,450m2 (500,000 sq ft) of exhibit space. Some of the exhibits on display will include haultrucks, hydraulic shovels and excavators, conveyors, continuous miners and tunneling machines. In addition, an array of computer equipment and software will be demonstrated. A new feature this year will be a helicopter pavilion, located in the Hilton Center. Helicopters and fixed-wing aircraft have become indispensable to many remote mining operations. NMA said that at least one full-size helicopter will be on display.

Jan 1, 1996

By A. Jahedsaravani, M. Massinaei, M. Zarie

Deep learning is a subset of machine learning that uses artificial neural networks for extracting high-level features from image data. In the present study, a soft sensor is proposed for the prediction of the flotation performance through froth features generated by the use of pre-trained convolutional neural networks. Several state-of-the-art convolutional neural networks (AlexNet, GoogLeNet, VGGNet, ResNet, and SqueezeNet) pre-trained on the ImageNet database are used to predict the metallurgical performance of two flotation systems. The first case study is a batch copper flotation system video-captured over a wide range of process conditions. The second case study is an industrial coal flotation column equipped with a continuous video recording system. The pre-trained networks are used to extract features from the froth images, and these features are subsequently used to predict the flotation conditions and performance. The prediction results by the pre-trained algorithms were compared with the traditional image processing algorithms. This demonstrates the ability of the pre-trained structures to generalize to images outside the ImageNet database. GoogLeNet outperforms other network architectures and provides more accurate predictions of the flotation process behavior and performance.

May 5, 2023

By D. R. Nagaraj, Napoleon Tercero, Raymond Farinato

Historically, as for most reagents used in flotation, the wide-spread use of dialkyl dithiophosphinates as collectors in practical applications has preceded a detailed scientific understanding of how they work. Dialkyl dithiophosphinates are a technologically and commercially important class of collectors used in the flotation processing of Cu-Au, complex polymetallic, and precious metal ores. Plant usage has demonstrated that dithiophosphinates exhibit higher selectivity and flotation rates for Cu sulfides, galena, and precious metal values in the presence of other gangue sulfides, than the traditionally used collectors such as dialkyl dithiophosphates and xanthates. They also have an attractive health, safety, and environmental (HSE) profile. Although dithiophosphinates received little attention in the past in the flotation research community, recently, there has been significant interest in this chemistry, and numerous studies have been conducted to understand the fundamental interactions of dithiophosphinates with several base metal sulfides and precious metals. A critical overview of fundamental studies, laboratory ore flotation, and plant practice of dithiophosphinates is given in this paper. The findings from these studies are rationalized and explained by drawing on concepts and insights from coordination chemistry. A comparison between the interactions with various minerals and metals of dithiophosphinate and dithiophosphate analogues brings out some of the subtleties that seemingly minor changes in collector chemistry can make. The critical overview and analysis given here is useful in identifying gaps in knowledge regarding this important class of compounds. This in turn can provide a basis for the design of studies to advance our understanding of dithiophosphinate flotation performance.

By J. D. Davis

THE carbonizing properties of one medium- and and five low-volatile coals from West Virginia and one high-volatile A and two medium-volatile coals from Pennsylvania were determined by 800° and 900° C. BM-AGA carbonization tests and expansion tests in the sole-heated oven. Plastic properties of the coals and the yields and quality of their cokes and other carbonization products were determined. The low-volatile coals comprised a mine and a coke-plant sample of Pocahontas No. 6-bed coal from the. Black Eagle No. 1 mine, Wyoming County, W. Va.; a mine sample of Pocahontas No. 6 bed from the Louisville mine, Mercer County, W. Va. ; Davy Sewell bed was sampled at the Twin Branch mine, McDowell County, W. Va.; and Fire Creek bed was sampled at the Dunedin No. 1 mine, Raleigh County, W. Va. The medium-volatile coals were from the Fire Creek bed, Laurel Creek mine, Greenbrier County, W. Va.; Lower Kittanning bed, Springfield No. 4 mine, Cambria County, Pa.; and Upper Kittanning bed, Springfield No. 6 mine, Clearfield County, Pa. The high-volatile A coal represented the Upper and Lower Freeport beds, Kent Nos. 1 and 2 mines, Indiana County, Pa. In addition to the coals listed, high-volatile A coal from the Pittsburgh bed, Warden mine, Allegheny County, Pa., a standard blending coal, was used in blends in this investigation.

Jan 1, 1950

By W. T. Robson

ONE of the problems encountered in any mine is the effect of increasing pressure manifested by increasing depth. Although the depth at which excessive pressure assumes serious proportion, and the manner in which it appears in underground workings, are influenced by a variety of factors, nevertheless the difficulty is present in all mines and its gravity increases with increasing depth. In the Kirkland Lake camp, as far back as seven years ago, mining had proceeded to depths sufficient to result in the formation of pressure great enough to cause violent disruption of masses of rock. It is proposed in this paper to deal with the effect of pressure caused by mining as observed at Lake Shore Mines, and to describe some of the methods which have been adopted to counteract it. There are many contributing factors in a study of the problem, and results vary widely in individual mines and in different localities. One feature common to all, however, is that there is ground subsidence, evidenced either by a gradual settling accompanied by crushing and shearing of the ore and wall-rocks, or the disruption of the ground surrounding the periphery of an excavation may take place suddenly, attended by more or less violent shattering of the rocks. Such violent failure of a mass of rock has been designated by the term rock-burst. The history of rock-bursts extends over a great number of years. They have occurred in some form or other in practically ali places where mining operations, at all but very shallow depths, have been carried out. Since the theoretical aspects of the subject have been dealt 'with at great length by capable and experienced writers (1), the present paper will give only a brief résumé of the theories propounded by those engaged in deep mining operations in various parts of the world.

Jan 1, 1940

By B. Samanta, S. Bandopadhyay

Ore grade modeling of a placer gold deposit is considered a challenging problem even today. Typically, gold-bearing deposits show extremely erratic and unpredictable grade variation. This is principally because of isolated occurrences of gold metal within a few high-grade pockets. Because of sporadic fluctuation of high-gold-grade distribution, the overall spatial continuity of the deposit becomes poor. This type of variation is often described by a lognormal or highly skewed frequency distribution, and the spatial continuity of the deposit is characteristically represented by a variogram model that exhibits a high nugget component. Further complicating the matter is the sparse availability of drillholes to capture such erratic variation. Due to the prohibitive cost of drilling, gold grade and reserve estimations are typically carried out using insufficient exploratory data. Use of a traditional estimation technique on limited data often produces an unreliable ore grade model. Kriging and its nonlinear variation, lognormal kriging, are frequently used in gold deposit modeling (Rendu, 1979; Journel, 1980); however, kriging is flawed by the smoothing effect. Moreover, though kriging is known to be globally unbiased, it is not free from conditional bias. As a result, if a deposit is modeled using the traditional kriging technique, a high-grade zone can be predicted to be a low-grade zone and vice versa. Predicting high grade as low grade results in a missed opportunity to exploit profitable ore. On the other hand, prediction of low-grade ore as high-grade ore might result in financial loss for a mining operation. Thus, the use of kriging for ore grade mapping of a gold deposit may not be recommended. Estimation techniques (including kriging) can produce an estimate with minimum error in a minimum-error variance sense. However, no matter which estimation technique is used for grade modeling of a highly erratic deposit like gold, the error margin is bound to be high. Therefore, any grade prediction made for an unknown location is associated with high uncertainty. Since various mine-planning operations, including derivation of grade tonnage curve, pit design and economic analysis of the deposit, are based on estimated grade rather than true grade, a mining project evaluation that depends upon estimation will be subject to considerable risk. Thus, the successful design of a mining project not only depends upon accurate grade estimates, but also upon accurate assessment of uncertainty, for predictive grade is equally important. Although the kriging standard deviation is used as an indicator of uncertainty for prediction, it is flawed by characteristics related to a data-independence property. This study, therefore, investigates the stochastic simulation technique of conditional simulation for ore grade modeling of a placer gold deposit at Nome, Alaska. It is expected that the research will provide a better solution to ore-grade deposit modeling than the kriging technique because (1) conditional simulation preserves spatial continuity as well as reproduces the data histogram, thus avoiding the smoothing problem; and (2) generation of multiple realizations helps to accurately quantify the uncertainty about grade values in the deposit.

Jan 1, 2009

By John Babcock, Bryan C. Smith

In a partnership between Luck Stone Corporation and Loudoun Water, a 42” (1.067m) steel pipeline was constructed along the perimeter of an extensive permitted reserve of diabase rock Luck Stone was about to begin mining. Loudoun Water provides drinking water and wastewater services to over 75,000 households in Loudoun County, Virginia. In discussions to establish the 30-foot (9.1 meter) easement for Loudoun Water within the permitted reserve of diabase rock, Luck Stone and Loudoun Water agreed on the following basic conditions: • Luck Stone could execute production blasting as close to the easement as physical conditions of overburden depth permits. We estimated the minimum distance to be about 75-feet (22.86 meters) from the centerline of the pipe. • Loudoun Water would install strain gauges on the pipe every 500-feet (152.4 m) along the entire length of the future reserve area. This resulted in the installation of 18 strain gauges. • Luck Stone would contract a third-party vibration monitoring company, agreed to by Loudoun Water, to monitor the strain gauges and provide seismograph reading at appropriate locations along the pipe as mining progresses. All information would be provided to Loudoun Water. • Luck Stone’s blasting will be conducted in a manner that ensures the recommended strains are not exceeded.

Jan 1, 2019

By H. C. Jennison

Two distinct types of defects occur at times in copper wire as a result of the use of dies of improper design or undesirable wire-drawing practice. The conditions under which these defects may be produced, as well as precautions to be taken in order to prevent them, have been known to The American Brass Co. for many years. The quality of the copper wire bars and rods has too often and unjustly been held responsible for these particular defects and it is to correct any such belief that this paper is presented. An extremely high quality of electrolytic copper has been supplied to the trade by all refineries for the last 20 years at least. The purity of the copper would average well above 99.900 per cent. The casting of the wire bars has been handled in a generally satisfactory manner. The bars have been cast sound, with a flat to slightly crowning set and have been free from sloppy edges, cold sets, etc. In other words, the wire bars have met A. S. T. M. specifications and have been generally satisfactory. For the most part, they have been everything that could be desired from a quality standpoint yet most of the wire mills in this country and in Europe have at times held the quality of the copper responsible for the two types of defects described in this paper. As a matter of fact, these defects are produced entirely in the wire mills. The author has visited many of the large wire mills in the United States and in Europe to investigate these defects. In some cases the trouble has been so serious that the wire mill has ceased operations. At times the wire mills are reluctant to believe that they are responsible for the defective product. The effect of die design, wire-drawing practice, etc., upon the quality of copper wire has received' little study on the part of wire mills, particularly those that have commenced operations in the last few years.

Jan 1, 1930

By Marwan M. Mohammed, Hani S. Mitri, Wilfrid Comeaul, Baoyao Tang

In many parts of the world, rockbursts have become a major problem of mining at depth. As orebodies are being mined deeper, rockburst phenomena have become familiar to deep hard rock mines. Rockbursts are generally characterised by sudden release of energy in a volume of highly stressed rock, which can cause local violent failure of the rock mass around the opening. One method of controlling these failures is to precondition the rock mass by detonating fully confined explosive charges at the appropriate locations. This method known as destress blasting, was first tried in the deep South African gold mines (Roux et al., 1957), and was widely used later in Canada, United States, France, Poland and Japan.

Jan 1, 1999

By G. H. Lind

New South Wales has a successful history of pillar extraction stretching back more than 60 years. Various methods of pillar extraction ranging from the rib pillar methods (such as the Wongawilli system) to the more recent pillar stripping techniques (similar to those used in the USA) are discussed in this paper. These discussions are based on the experiences of the author stemming from a recent research tour of seven underground pillar extraction operations in New South Wales as part of the Coaltech 2020 collaborative research initiative. Some operational issues of each site visited are presented before some general comments pertaining to the overall success of pillar extraction in New South Wales are discussed. Generally pillar extraction in New South Wales is on the decline in favour of longwalling. However, the pillar extraction that is conducted is done so along specific guidelines to ensure their success, and these are also discussed.

Jan 1, 2002

By T D. H McGrath, W P. Staunton

Benchmarking, comparing an operation or process with the industry standard, is known to be a useful method for identifying plant optimisation opportunities, and in many cases providing the pathway to realise the benefits. The difficulty is generating the database of plant data necessary for a benchmarking exercise. Larger companies can benchmark internally; this option is not available to smaller companies, and the full value can only be realised with a comprehensive “industry wide” approach.The Gold Technology Group at Curtin University through the AMIRA P420 series of projects has undertaken several comprehensive metallurgical industry surveys in the gold industry over the last two decades. Analysis of these surveys has demonstrated areas where many operations can benefit from re-assessment of their operating practices.This paper will review the work undertaken by the Group in this area, in particular the 1999 surveys of gold companies in the Australasian region, and the 2012 international survey of the industry. The challenges of, and opportunities arising from these surveys will be discussed. Some of the highlights from analysis of these databases will be presented as well as noting changes in processing practices observed by the Group over the last 20 years.CITATION:McGrath, T D H and Staunton, W P, 2018. Keeping up with the Joneses – the value of industry surveys and benchmarking, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 509–516 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

This Bureau of Hines report on underground mine communications addresses methods and equipment to meet the communication requirements of working sections and places of coal and metal-nonmetal mines. A review of the status of trapped miner detection is also presented.

Jan 1, 1977

Recent U.S. mine disasters identified a need for improved training of miners in escape from mine fires and explosions. Researchers at the National Institute for Occupational Safety and Health?s (NIOSH) Spokane Research Laboratory (SRL) have designed fire-escape training software for use in a mine-safety training course. The software allows four trainees to work together in a virtual world via a computer network. Trainees responded favorably and showed a marked improvement in locating the proper evacuation routes on subsequent trials. In collaboration with the Pittsburgh Research Laboratory (PRL), a more elaborate fire evacuation scenario is being developed. Further study is needed to confirm that virtual training will translate to improved safety outcomes in the real world. Keywords: virtual reality (VR), safety, training, mining, mine fire evacuation

Jan 1, 2009

By T. R. Ellis

"Editor’s Note: This is an expanded abstract. The full report is available on SME’s website at http://www.smenet.org/publications-resources/ resources/sme-valuation-standards-tutorials.The author has three goals for this review of mineral valuation standards internationally.1. To place the SME Standards and Guidelines for Valuation of Mineral Properties (SME Valuation Standards) and International Mineral Property Valuation Standards template (IMVAL Template) within the global context of existing mineral valuation standards.2. To review the current status of harmonization of each International Mineral Valuation Committee (IMVAL) member’s mineral valuation standards (or code) with the IMVAL template and suggest remedies for issues found.3. To suggest future enhancements for the IMVAL Template and SME Valuation Standards, and to suggest future roles for the IMVAL and SME committees. From the author’s review, Ellis draws the following conclusions.The SME Valuation Standards comprise a minimum set of principles-based standards and guidelines for developing and reporting valuations of mineral properties (including petroleum properties) for public and private use, subject to jurisdictional requirements. The standards are also designed to provide mineral valuation guidance that supplements application of the International Valuation Standards Council’s International Valuation Standards (IVS) and the U.S. government endorsed Uniform Standards of Professional Appraisal Practice (USPAP), published by the Appraisal Foundation.The SME Valuation Standards is the first set of valuation standards developed by a minerals institute adopting and modifying the IMVAL template. As a result, the SME standards are essentially totally harmonized and otherwise aligned with the IMVAL template. IMVAL was initially conceived in 2012 as a discussion body to aid harmonization of each member’s valuation standards, by modifying to function the same. IMVAL primarily developed the IMVAL template, published in July 2016, to produce an agreed reference framework of essential mineral valuation guidance content as the goal for harmonization of the Australasian Code for Public Reporting of Technical Assessments and Valuations of Mineral Assets (VALMIN Code), The South African Code for the Reporting of Mineral Asset Valuation (SAMVAL) and the Canadian Standards and Guidelines for Valuation of Mineral Properties (CIMVal standards and guidelines). The harmonization would result from each mineral valuation standards committee modifying its standards to operate similarly to the IMVAL template, producing valuation reports with similar content and value for the same mineral property. The template is also available for other bodies to adopt and modify for their regional setting’s needs, as SME did, or use as a convergence goal when updating an existing standard."

Jan 2, 2018

By H. K. Shearer

Drilling for oil and gas in Arkansas in 1934 showed more activity than in any year since 1929; with a total of 96 completions, including 36 oil wells, 1 gas well and 59 dry holes. Of the producers, the lone gas well and 35 oil wells were in old fields, and one wildcat producer opened a new pool. Of the dry holes, 16 were in or near fields and 43 were wildcats. The total reported initial daily production of the oil wells was 9013 bbl., averaging 252 bbl. per well. Active drilling operations numbered 65 at the close of the year, compared with 26 at the beginning.

Jan 1, 1935