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By Russell B. Dix

Laboratory column leach tests are used routinely to evaluate gold and silver ores for heap leaching. The tests are fairly straightforward. The ore to be tested is placed into an appropriately sized leach column. Then an alkaline cyanide solution is applied to the ore and the effluent solutions are collected. The effluent solutions are then put through a column of activated carbon to recover the gold and silver in solution. Zinc precipitation may also be used for silver ores or if the ore contains a significant amount of soluble silver in addition to gold. The length of the leach time in the tests is mainly a function of how quickly the precious metals are recovered from the ore. At the completion of the tests, the tailings are assayed and the recoveries determined from the calculated head grades. The amount of ore to be used for a test is partly a function of its crushed size. The coarser the size, the larger the sample size for the column. A typical small-scale laboratory column test on ore crushed to -12 mm (-0.5 in.) would usually be conducted in a 100- to 150-mm-diam (4- to 6-in.-diam) column 2 m (6.6 ft) in height, containing about 20 to 45 kg (44 to 99 lb) of ore. A comparable test on the same ore crushed to 50 mm (2 in.) would be conducted in a 200- to 300-mm-diam (8- to 12-in.-diam) col¬umn 2 m (6.6 ft) in height, containing about 80 to 200 kg (176 to 441 lb) of ore. Larger-scale tests can be run by increasing the column heights and diameters. Conducting larger-scale tests results in increased costs for sample procurement, preparation, and running of the tests. The additional data obtained from

Jan 1, 1989

By Xinhua Wang, Qiangqiang Wang, Yubin Li, Shusen Li, Lifeng Zhang

"Numerical simulation on the fluid flow in a Flow-Control Mold (FC-Mold) were performed. The motion of inclusions were calculated. With FC-Mold, the flow pattern and surface velocity become more symmetrical, and at higher casting speed the velocity of liquid steel in the top region of the mold was largely reduced with the highest velocity of the meniscus reducing from 0.65 mis to 0.4 mis, and the meniscus shape became flatter. With FC-Mold, more inclusions approached to the surface of the slab and the amount of inclusion in the center of mold became fewer. Larger inclusions were easier to remove, however, the EM filed of the FC-Mold could hardly improve the removal of inclusions from the molten steel.IntroductionElectromagnetic brake technology is an effective method to control the flow pattern within continuous casting mold, together with other casting parameters, nozzle design and mold geometry [1-5]. Due to the interaction between the applied magnetic flux and the conductive molten steel inside the mold cavity, a force is generated in the direction opposite to the jet flow, which can decelerate the high speed steel jet from the SEN ports. The potential benefits include fewer surface and internal defects, fewer inclusion especially at higher casting speed. However if used imperfectly, electromagnetic forces can have opposite effect [6]. Numerical models are the best tool to optimize electromagnetic flow control. In the current study, numerical simulation was performed to investigate the flow field in a continuous casting FC-Mold, and the effect of different operation parameters on the flow, surface level and velocity in FC-Mold were discussed."

Jan 1, 2013

By Joel N. Van Sant

An investigation was conducted to study possible sources of Utah refractory and structural clays that could be used for the manufacture of refractories and light or buff burning heavy-clay products. A field study was made and the clay samples tested to determine their firing characteristics. Results of the Bureau's work indicate many small noncommercial deposits of hypogenic clay occur in igneous rocks. Commercial hypogenic deposits are mostly halloysite clay developed by hydrothermal replacement of limestone. The high firing shrinkage of halloysite precludes its use as a refractory, however, halloysite produced at the Dragon Mine south of Eureka, is used fur making oil catalysts. Clays and shales suitable for low heat duty refractory products are found in the Manning Canyon shale, in shales associated with coal bearing rocks, and in the Dakota formation. Some of the clays from the Dakota formation are also suitable for high-duty refractory products.

Jan 1, 1964

By John F. Wiss

A series of controlled experiments was conducted at four surface coal mines to study the effects of certain blast parameters upon the ground and air vibration. Preliminary scale-model blasts were conducted at a quarry to provide basic data. It was found that the amplitudes of the ground and air vibration were controlled by the maximum explosive weight per delay. Either cube root or square root scaling could be used for the seismic amplitudes, and cube root scaling could be used for the overpressure amplitudes. Both amplitudes were not significantly affected by the total charge weight per blast, the attitude of the boreholes, or the charge length or diameter. The overpressure amplitudes were affected by the charge depth, the use of cover over surface detonating cord, and the use of adequate stemming. The length of the delay intervals and the spacing of holes were important in determining' the potential fur reinforcement of the amplitudes in certain directions from the blasts. In downwind directions from the blast, the attenuation of the overpressure with distance decreases. Surface terrain did not significantly affect the overpressure amplitudes within the range investigated. The type of overburden affects the generation of both amplitudes and the propagation of the seismic amplitudes. Spectral analysis of the ground and air vibration is reported. A bibliography of pertinent literature is included as an appendix. A scaled distance of 300 ft/lb1/3 should produce a peak particle velocity of less than 1 ips and an overpressure of less than 128 dB linear peak. For square root scaling, a scaled distance of 75 ft/lbl/2 should limit the ground vibration to less than 1 ips.

Jan 1, 1978

By K. Muralidharan, P. R. Rao, M. Momayez, K. A. Runge

The evolution of trapped geothermal heat in hot underground mine along with emission of toxic gases and dust during mine activity makes the mine environment unfavorable is hazardous to worker’s health. This imposes significant demand on cooling and ventilation systems. As a result, substantial costs are incurred while implementing environmental regulation processes to dissipate the heat and provide comfortable working conditions. Thus, as an alternative, the development of cost effective materials to act as efficient thermal insulators is on the rise. Thermal conductivity is an important property that is a direct measure of a material’s ability to facilitate/deter heat flow. In addition to their superior chemical resistance, adequate mechanical strength, abrasion and fire retardant as well as environmental benefits in comparison to existing building materials such as ordinary Portland cement, aluminosilicate based geopolymers are now gaining widespread interest as promising thermally insulating and sustainable materials. This paper begins with an overview of geopolymers, transitioning into a discussion of recent developments in the field of geopolymer development as a thermally insulating material broadly classified into: filled geopolymers and porous geopolymers resulting in structures with enhanced ability to impede heat flow.

May 9, 2020

By V. L. SKITSKY

Geophysical Abstracts are published by the Division of Geophysical Explo- ration of the U. S. Bureau of Mines as an aid to those engaged in geophysical research and exploration. Inasmuch as geophysicists in the field may have little opportunity to consult libraries, the policy of the Division is to provide abstracts suffi- ciently informative in themselves to keep readers abreast of literature and patents published in the United States and abroad. - DISTRIBUTION. Abstracts 1-86 were issued as Information Circulars by the Burca of Mines; Abstracts 87-111 appeared as Bulletins of the Geological Survey; Abstracts 112-127 have been published as Information Circulars by the Bureau of Mines; succeeding issues will be resumed by the Geological Survey.

Jun 1, 1947

By Gene R. Reid

The contract objective is the development of an Automatic Fire Control System for Mobile Underground Metal Mining Equipment. The Phase I Report, which described the projected data handling plan, was published on July 24, 1975. The Phase II effort covered the period from July 24 through December 2 and accomplished the following objectives: ? Acquisition of data in accordance with the project data handling plan. Data were acquired through visits to twenty mine sites in ten states and Canada; visits to Bureau of Mines and MESA facilities; visits to mobile equipment manufacturers; and an extensive literature search. ? Analysis of accumulated data which provided the following specific types of design inputs: selection of the type of mobile underground equipment found to represent the greatest overall fire hazard; typical operating conditions for the vehicle; characteristics of the reported fire experiences; and performance, cost and maintenance factors affecting potential purchases of automatic fire control systems for underground mining equipment. ? Development of the AFCS design concept. Utilizing the data analysis results and considering the state-of-the-art of fire control system components, a recommended design concept was developed with particular emphasis placed on the need for a low cost and reliable system. Design trade-off studies are provided for the recommended system and for four alternate system concepts.

Jan 1, 1975

By Carolina Rouillon

El presente documento señala dos experiencias aplicadas en la mina Yanacocha y Pierina exitosas donde se emplea las geomallas como parte del mejoramiento de suelos blandos con la finalidad de distribuir uniformemente las cargas impartidas por los grandes equipos mineros hacia la subrasante de mina típicamente conformada por suelos con alto contenidos de limos y arcillas húmedas y saturadas. Asimismo, los beneficios obtenidos por usar las mallas, no se limitan al ahorro en costo material de relleno, sino que se logra un mejor desempeño- en tanto optimiza la superficie de circulación de los vehículos mineros, reduciendo los tiempos de operación, así como prolonga los períodos de reparación y mantenimiento.

Sep 21, 2013

By Peter K. Kaiser

Planning and design of deep underground mines involves a process of complex three-dimensional data integration utilizing information from exploration (geology, rock mass characteristics), engineering (mining method, excavation geometry, stress) and operations (time, in the form of sequencing). As new logging and monitoring technologies are being developed, the amount and data complexity becomes overwhelming and decisions are often made based on only a small part of the available data. Recently, Laurentian University opened a state-of-the-art Virtual Reality Laboratory (VRL), a Mining Exploratorium that is unique in the world of mining and offers an exceptional data interpretation environment for mine planning and design. The Mining Exploratorium combines a large format spherical stereoscopic projection system, equipped with high definition projection providing the highest resolution of active stereo in the world today, with advanced features of earth modeling software. Combined, this creates the first virtual reality facility geared specifically to the interpretation of mine geometry, geology, geochemistry, microseismicity, geomechanics and mining data sets. This paper demonstrates how value can be added to the mine planning and design process by utilizing this unique tool in the mining decision-making process via better comprehension of spatial relationships of data and by interpreting the data in a collaborative immersive virtual reality environment.

May 1, 2002

By S. K. Bradford

(Pittsburg Meeting, March, 1910.) FOR years past I have traveled in quest of promising mining-properties, over almost impassable mountain-trails to remote places in the mining-regions, usually, many miles from an assay-office. If, upon examination, the formation and the ore-deposit appeared favorable, a quick determination of the value of my samples was necessary, in order that I might take intelligent action with reference to the acquisition of the property. A journey with my samples to civilized regions often meant weeks of delay, and perhaps loss of opportunity. How many, under similar circumstances, have returned with their assay-results from such a journey, only to find that some audacious speculator had " optioned" the property ! True, a first payment could have been made and the chances taken on the results; but experience has taught that rich-looking ore is not of necessity valuable. Personally, I would not hazard a ten-dollar bill on any property without first determining by assay the value of the ore. To carry the usual complete assay-paraphernalia over such mountain-trails was impracticable by reason of the loss of time involved, the great expense of transportation (charged according to weight), and the fact that a few such trips would almost certainly wreck the outfit. For these reasons I began a process of elimination and substitution which finally enabled me to carry, in an ordinary 26-in. valise, sufficient apparatus and supplies for, say, 100 assays of adequate commercial accuracy. My final outfit was as follows: APPARATUS. Small hammer; steel mortar (2.5 in. wide, 3 in. high, with stand sawed off flat, so that it can be used as an anvil and for

Jan 1, 1911

By Thomas Glück

Established and emerging mining companies face significant challenges in managing their operations and projects. Outcomes often do not meet the expectations of all the stakeholders of particular developments. This paper reviews typical management practises used by mining companies to undertake mining projects and improve their operations. A simple application of the House of Quality (HOQ) tool used in the Quality Functional Deployment (QFD) management approach is presented. It is shown that a QFDMMPtg approach could lead to innovation in mining processing plant development practice.

Jan 1, 2015

By Willie M. NeSmith, W. Morgan NeSmith, Alan Roach

"In 2013, Augered Cast-in-Place (ACIP) piles are a mature foundation technology throughout the United States. General guidelines for the design and construction of ACIP piles are available along with numerous references for design in specific North American geologies. In fact, the current generation of contractors and geotechnical practitioners might view ACIP piles as just another deep foundation option to be considered, along with driven piles, drilled shafts and others. This acceptance has developed, however, over a 60-plus year period.The term, Augered Pressure-Grouted (APG) pile is often used when referring to ACIP piles because the piles emerged out of construction processes at the Intrusion-Prepakt firm in the late 1940s. The company’s specialty was pressure grouting and preplaced aggregate concrete. The grouting was typically accomplished by driving a pipe to a target level and then injecting grout under pressure. In some soil conditions, it was necessary to use an auger to reach the desired grouting depth. In these circumstances, the grout pipe was driven beside the auger and grout was pumped as the auger was withdrawn. The grout pipe was then withdrawn as well. This was the genesis of the APG, or ACIP pile, and many piles were installed using this technique. The patent application, “Method for Forming Piles” was filed by Raymond Patterson of Intrusion-Prepakt in 1951, and the patent was granted in 1956. The process was eventually modified when a suitable hollow-stem auger was developed. Licenses were granted to the Lee Turzillo Contracting Company and Berkel & Company Contractors, Inc. in the late 1950s. Each of the three companies Patent, LicensesThe patent application, “Method for Forming Piles” was filed by Raymond Patterson of Intrusion-Prepakt in 1951, and the patent was granted in 1956. The process was eventually modified when a suitable hollow-stem auger was developed. Licenses were granted to the Lee Turzillo Contracting Company and Berkel & Company Contractors, Inc. in the late 1950s. Each of the three companies coined their own terms for the piling process: “Pakt-In-Place” for Intrusion-Prepakt, “Auger Pressure-Grouted” for Berkel and “Augercast” for Turzillo. Over time, “Augercast” was frequently used as a generic term for the system. The installation of these piles was, and still is, a highly nuanced process; “contractor dependent” is a term often seen today. Intrusion-Prepakt, Berkel and Turzillo all had personnel who were part of the original group that developed the system and who appreciated the craftsmanship involved in forming sound piles."

Jan 1, 2013

By Roger F. J. Adam

This report summarizes the principles of safely working steep coal seam using longwall mining methods. It presents the state-of-the-art and identifies the problems which result from seam inclination. Details are given on foreign longwall faces achieving good records of safety and productivity when mining on 30 degree and 50 degree inclined seams. Recommendations for further research are suggested.

Jan 1, 1981

By B. Simser

Rockbursting around underground excavations continues to be a core risk for many deep mining operations. Numerous advancements in mine design, preconditioning, monitoring, mining equipment, exclusion zones, and ground support have significantly lowered the risk to mine workers. As mining continues in deeper, more challenging environments, a multitiered approach to rockburst risk mitigation, starting with mine design, is required. Both the overall mine sequence, for example, avoiding converging mining fronts, and local design “stick handling” can play an important role in risk reduction. Rockburst case studies dating back to the late 1990s up until 2024 are used to highlight risk factors and risk mitigation (tactical and strategic). Examples from several deep hard rock mines are used, generally in high horizontal stress fields (k ratios 1.5 to 2), and strong brittle rock (> 200 MPa unconfined compressive strength). Mining induced stresses as well as high in situ stress due to depth are discussed. The context is Canadian mining, which typically has highly mechanised operations, large openings and equipment. Examples from a narrow vein mine and shaft sinking are also given because neither environment is simple to mechanise, highlighting the need for other risk mitigations. A “sieve” analysis based on mine incident reports is used to show how a multi-tiered risk management plan can lower exposure to violent ground failures. A few incidents still make their way through the “sieve,” indicating a need for further improvements. Thoughts on future/ current developments, and their strategic importance are given. Ground support is the last line of defence. The proliferation of multiple styles of yielding tendons and support systems has made many choices available to rock engineering professionals. Despite the increased availability of dynamic ground support components, there are still difficulties getting clean load transfer to bolts, determining support demand, monitoring loss of capacity over time/mining, and evaluating true system capacity. Virgin development in deep high stress brittle rock can result in high strainburst exposure prior to any stoping operations. The mining process must reduce worker exposure to unsupported rockmasses. Successful preconditioning in a shaft sinking operation, the use of high early strength shotcrete, and mechanised equipment are also discussed.

Nov 24, 2025

By E. D. Gardner

This bulletin, which discusses open-cut mining at the metal mines of the United States, is the last of a series of such papers by the Bureau of Mines describing the principal methods of mining.4 Open-cut mining is applicable to flat-lying mineral deposits relatively near the surface. Vein deposits seldom are amenable to this method, although outcrops of veins sometimes are worked as open pits. Most of the iron ore of the country is mined from open pits; according to the Minerals Yearbook, 67.4 percent was mined from open pits and 32.6 percent from underground mines in 1937. Open-cut mining is relatively new in the copper industry but yields more copper than any other method; in 1937 about 52 percent of the copper ore mined in the United States was taken from open pits. Lead-zinc ore has been produced from open pits in the Joplin (Mo.) district, but most of the deposits in this area, although flat-lying, are too deep to be mined economically by the open-cut method. In 1937 one company at Oronogo, Mo., was stripping overburden and mining mixed oxidized and sulfide ores by this method.

Jan 1, 1941

Duty on Lead Reduced. -On December 28, the President signed H.R. 5047 which reduces the duty on unwrought lead from 3.5% ad valorem to 3% ad valorem, with a floor level of 1.0625 cents per pound, effective retroactively from January 1, 1980, through June 30, 1983. Pacific Northwest Power Bill Passed. -On December 5, the President signed S. 885 which will enable the Bonneville Power Administration to guarantee 20-year contracts to its 15 major industrial customers in exchange for higher rates. In effect, the bill will have industrial customers pay some of the costs of building additional generating facilities in the Northwest, of which thermal units are expected to be a major part. BPA supplies power to six primary aluminum producers which operate eleven plants having over 30% of the primary aluminum capacity in the United States.

Jan 1, 1980

By Shelby Z. Palya

"The Bureau of Mines was established in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mining-substances; to promote health and safety, in the mineral industries; to conserve Material resources , and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other Mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-Bureau publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable. This issue describes reports and articles published during the period January 1, 1975, to December 31, 1979. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960; 2 the 50-year list, of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960; 3 the 5-year lists of publications and articles, from January 1, 1960, to December 31, 1964,, from January 1, .1965, to December 31, 1969,5 'and from January '1, 1970, to December 31, 1974; and the annual ,lists of Bureau publications and articles from January, 1 to December 31, 1975,7 from January 1, to December 31, 1976,8 from January 1 to December 31, 1977, and from January 1 to December 31, 1978."

Jan 1, 1981

By W. R. Dengler

Dynatec Mining Limited contracted to sink a lS00 metre (4960 ft.) concrete lined shaft for Falconbridge Nickel Mines in Sudbury, Ontario, Canada. The shaft is 6.3 metres (20.S ft.) in diameter inside the concrete lining and is equipped with steel furnishings. Dynatec used the owner supplied 4.6 metre (l5 ft.) diameter double-drum hoist to sink the shaft with 12.S tonne buckets for muck removal and 4 cubic metre concrete buckets for concrete placement. One of the unique features of the shaft sinking operation is the use of a four-boom electric hydraulic drill jumbo permanently mounted in the shaft sinking stage. This paper will describe the performance obtained with the electric hydraulic drilling equipment and the high capacity muck removal and concreting equipment.

Jan 1, 1992

By Frank K. Cameron

"The DepositsThere are two large deposits or groups of deposits of potash salts which, at the breaking cut of the great world war in 1913 and for several decades preceding, were practically the only commercial sources of supply for the entire world. In both cases the origin of the deposits was sea water, the potassium salts being deposited by desiccation, but there were modifying factors which were not entirely the same in both cases so that well defined and important differences exist in these deposits. The larger and better known group, called the Stassfurt Deposits, are in Germany in the region about or adjacent to Magdeburg and Halberstadt. The general character of these deposits and the methods for recovering potash from them have been frequently described, not only in technical publi¬cations, but in the non-technical propaganda long maintained by the Kali Syndikat, an organization founded on a ""cartel"" with the supervision and support of the late Imperial German Government.Less well known are the smaller though nevertheless extensive deposits in the neighborhood of Mulhouse in Upper Alsatia, which were also under the control of the Kali Syndikat at the breaking out of the war but have now passed to French control, with the reentrance of Alsace into the French Republic.The Alsatiaa deposits, while less extensive than the German deposits, are, nevertheless of great magnitude. They occupy a large part of the area between the Vosges Mountains and the River Rhine, from Col¬mar on the North to Mulhouse on the South. Indeed a few borings on the East bank of the Rhine indicate that the deposits may extend under the river and to some distance beyond Buggingen Linken, Baden, though it has not been Shown as yet that this extension is of commercial significance.As is well known, the Stassfurt potash occurs as potassium chloride or potassium sulphate or both salts, intimately mixed with salts of sodium, magnesium eau& calcium (lime) and contaminated with substances. insoluble in water such as ferric oxide, clay etc. The potash salts are segregated in more or less extensive 'pockets' throughout the salt mass, these segregations departing usually from the horizontal. But the main ""potash region"" is a stratum varying from 30 to 150 feet in thickness and at a depth requiring shafts 5000 feet."

Jul 1, 1919

By Dave Kay, Young-Suk Song

To meet the needs of South Korea's rapidly expanding economy, a large number of infrastructure projects are under way to improve transportation efficiency within the nation. These projects include high-speed rail links between major population centres and improvements to the road network. Being densely populated and geographically mountainous, infrastructure development in Korea requires a significant amount of tunnelling. Owing to the predominantly hard granitic nature of rock, drill and blast is the preferred method of tunnel advance. The Korean tunneller, however, faces the same pressures as those of his international counterpart in that both cost and production targets need to be achieved while meeting expectations of both community and regulator.

Jan 1, 2005