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By E. R. Palowitch

On February 5, 1973, Eastern Associated Coal Corp began shortwall mining in their Federal No. 1 Mine, thus marking the first attempt in the United States at modern shortwall mining, i.e., using a continuous miner to extract coal open-ended from pillars 100 to 200 feet wide, under the protection of a self¬-advancing roof support system (1)1/. Since then, four additional shortwall faces have been operated. While the number of face-years of shortwall experience in the United States is limited, this experience has been anything but uniform. Differences in operator motivation, coalbed parameters, geologic conditions, panel dimensions, and face equipment all have contributed to a wealth of knowledge which can provide guidance for the design of future shortwalls. The purpose of this paper is to review the history of shortwall mining in the United States and to assess its value to the U.S. coal industry in terms of the health and safety of the miner, the percentage of coal recovered, coal production, worker productivity, and relative cost performance.

Jan 1, 1976

By R. Pelton, Z. Dai, S. Yang

ABSTRACT Hydrophobic polystyrene nanoparticles were evaluated as potential flotation collectors for pentlandite. The flotation of hydrophilic glass beads demonstrated the nanoparticles’ ability to induce flotation. Deposition of nanoparticles on glass surfaces increased the contact angle and enhanced adhesion of the beads to air bubbles. High flotation recoveries were achieved when 5–10% of the bead surfaces were covered with nanoparticles. Surface functionalization—the addition of vinylimidazole to polystyrene nanoparticle surfaces—caused the nanoparticles to selectively deposit onto pentlandite surfaces in the presence of Mg-Si slimes. Ongoing work includes attempts to identify specific applications where nanoparticle collectors might be cost effective. _ KEYWORDS Flotation, Nanoparticle collector, Coverage

Jan 1, 2014

By Jean-François Stumper, Mario Moser, Mark Kruessmann, Volker Langer, Daniel Bastos Martins Cruz, Claude Meisch

The latest generation of probes and casthouse machines provide a wealth of data that has not been available a few years ago. The evaluation of this data gives direct feedback to improve the blast furnace efficiency, the equipment maintenance and design and it allows the early detection of critical or deviating process situations. A stable operation with lower operation and maintenance costs are the final customer benefits.

Oct 1, 2019

By J. R. Riding

In situ solution mining of uranium has environ- mental advantages over conventional mining. The leaching of uranium, however, alters the groundwater quality in the aquifer where the mining occurs. Currently, regulations require that the groundwater be restored to approximately its original condition. This paper, a summary of a study funded by the Bureau of Mines, reviews the state of the art in restoring groundwater quality after in situ uranium leaching. Current restoration practices discussed include disposal of liquid wastes in deep disposal wells and evaporation ponds, producing from all wells during restoration, and recirculating water purified in surface plants. Methods for predicting the effectiveness and cost of current techniques are presented. Possible alternative techniques are also described. Two restoration operations are discussed.

Jan 1, 1979

By J. F. Lewis

Believing that one of the essential points in mining, as in all other business, is to know the expense incurred in each particular department, I have carefully kept an account with each department for the past three years; and, as it may be of interest to some of our members, I herewith present it to the Institute, reduced to per centages of the total yearly expense, showing the cost for materials, repairs, expenses, tools, team accounts, powder, oil, and fuel, also for labor under its several heads: 1875—Materials. 1875—Labor, Repairs,...040 Expenses,....016 Team,. .. .. .017 Machinery,. .. .055 Tools,..006 Repairs,. .. .027 Improvements,.....030 Washer,. .. .076 Oil ..008 Pit,.. 178 Powder,..,043 Dirt,.. 130 Fuel,. .325 Superintendence,. ..050 .485 .516 100.1 1876—-Materials. 1876-Labor. Repairs,. . • .. .043 Expenses,......012 Team,.011 Machinery,. .. .090 Tools,..005 Repairs,... 027 Improvements,.....007 Washer,. .. .085 I,. ...,015 Pit,.. 139 Powder,. .. .. .030 Dirt,.. 160 Fuel,...321 Superintendence,. ..078 .444 .559 100.3 1877—Materials. 1877—Labor. Repairs,......102 Expenses,......019 Team,..031 Machinery,. .. .050 Tools,..030 Rrpairs,. .. .046 Improvements,....,031 Washer,. .. .057 I,...009 Pit,.....179 Powder,...035 Dirt,.. 162 Fuel,...200 Superintendence,. ..054 .457 .548 100.5 Average for the three years 1875, '76, and '77. Materials. Labor. Repairs,...062 Expenses,...016 Team,..016 Machinery,. .. .065

Jan 1, 1879

By R. G. Knickerbocker, T. E. Evans, D. R. Torgeson

"INTRODUCTION Sponge iron is a product resulting from the reduction of an iron oxide at such a low temperature that fusion does not occur, and the reduced particles retain substantially the same shape as the original ore. The removal of oxygen in the reduction process leaves the metal porous and reactive. Sponge iron may be compared in general to a chemically precipitated substance insofar as reactive properties are concerned. The high specific surface and the orientation of metallic structure are factors which probably contribute to the reactive properties of sponge iron.The term ""gaseous reduction,"" as applied to iron ores, required clarification. Strong evidence exists, for example, that ore is partly reduced to sponge iron by carbon monoxide in the blast furnace at temperatures around 800° C. at a point that may be as high as 30 feet above the tuyores. In 1923 and 1924, Sims and Wood attempted to reduce iron oxide with carbon in an Arsem vacuum furnace at 980° C. These investigators found that only 6 percent of the iron was reduced to metal when the iron oxide-carbon mixture was heated for 1 hour under evacuated conditions, whereas at atmospheric pressure 70 percent of the iron was metallized. Their results indicate that the process of iron-ore reduction at temperatures below the melting point of the ore may proceed largely, if not entirely, by the action of reducing gases even when the reducing agent is solid carbon. Therefore, the term ""gaseous reduction,"" as used heroin, is defined as a process in which iron ore is brought into intimate contact with a reducing gas produced in separate-equipment from the reduction chamber itself.A large amount of pilot-plant development on gaseous reduction of iron ores has been carried out by the Bureau of Mines at the Boulder Experiment Station and had as its objective the reduction of fine iron ore by means of producer gas. The use of use gas was prompted by two considerations: First, the possible utilization of large reserves of Western noncoking bituminous coals and lignites contiguous to iron-ore drewwing; and second, an investigation of the results that might be achieved in the pilot-plant gaseous reduction of fine iron ores by means of a relatively reducing gas. The results obtained, it was felt, would be of considerable value in indicating the direction which gaseous reduction experimentation must take for the development of a commercially practicable and economic process for the production of sponge iron."

Dec 1, 1946

By Raymond A. Binns

Exploration for high-value massive sulfide deposits on the ocean floor typically commences with a search for chimney fields in appropriate geological settings, followed by collection and assaying of standing chimneys. Individual chimney fields are generally too small in aggregate volume to constitute viable resources in their own right. Unless numerous small fields occur in reasonably close proximity, presence of plentiful sub-seafloor mineralization with acceptable metal tenor is the more likely requirement for potential exploitation. Expensive drilling is required to prove up mounds of collapsed chimneys, or dilatory sheets and veins or replacements of massive/semimassive sulfide (?stockworks? or ?manto?-like bodies) in underlying host rock. Where multiple targets have been defined, as many parameters as possible are desirable to help rank them for drilling.

Jan 1, 2011

By H. Dong

This paper presents a heat conduction model to determine the erosion profile of freeze linings in a ferronickel submerged arc furnace. Kirchhoff transformation was adopted to simplify the nonlinear equation governing heat conduction. The boundary element method (BEM) and Nelder-Mead simplex optimization method were employed to solve an inverse heat conduction problem. Erosion profiles could be obtained when calculated temperatures at sensor locations agreed well with measured temperatures. The model was validated by comparing the heat loss through the linings, which was calculated by BEM and integral operation after erosion profiles were obtained, with the value calculated from industrial data such as actual power consumption, tap-to-tap time, and ferronickel output. The optimal solution for the erosion profile could be acquired when the difference in heat losses calculated by these two methods is at a minimum.

Jan 1, 2014

By Hayel M. El-Naggar, Marawan M. Shahien

"Large capacity piles are important type of foundation elements that are needed in case of high column loads such as in tall buildings with large span between columns. In many projects, especially if the designer uses the concept of one pile supporting one column (Hamza, 2003a & b). The axial capacity of the large bored deep foundations can be further increased by grouting the shaft skin and the base of the pile. The increase in the capacity of the piles due to grouting can be tremendous. Thus grouting appears as an ideal solution for achieving more reliable foundation and greater savings (Littlechild et al., 2000). A data base of pile load tests of instrumented grouted piles is under development in a major study aiming to propose a simple method to estimate the axial capacity of large bored grouted piles. The data base include pile load tests from projects constructed in Egypt and abroad. The main goal of this paper is to analyze pile load test(s) from one project. The tested deep foundations included 1.2 m diameter and 1.5 m diameter piles and a barrette of size 1.0mx2.8m. The instrumentation of the tested piles and barrette allowed for the separation of skin friction and base contributions to the axial load. Further, the contribution of the skin friction of every layer along the pile shaft could be identified. The results of the analysis clarified how base and shaft grouting increased the axial capacity of the pile and decreased the settlements for certain load level compared to conventional un-grouted piles installed under similar conditions.INTRODUCTIONIn recent years, significant research has been carried out to develop new techniques which are suitable to withstand problems in major projects such as high applied loads in high rise building, large spans structures projects and structures designed using the concept one pile supporting one column (Hamza, 2003a & b). Base and shaft grouting of piles are one of these new techniques which aim at decreasing the settlements and increasing the capacity of the pile under axial load that became major requirements in large projects (Stocker, 1983; Mullins et al., 2001; and Hamza, 2015).Base grouting consists of injection grout under pressure at the base of the pile after the concrete is sufficiently hard. Field evidences showed that the ultimate end bearing of base-grouted piles could be as high as 1.5 that of non-base-grouted bored piles (Suckling and Eager, 2001). Further, field evidences was provided by Shahien and El-Naggar (2015) that showed an increase in end bearing resistance due to base grouting reached to 2 to 3 times that of non-base-grouted bored pile. On the other hand, shaft-grouting causes increase in the soil density in the zone which had been disturbed by the pile construction and thereby improves the shaft resistance of the pile. Field measurements by Gouvenot and Gabaix (1975), Stocker (1983), Robson and Wahby (1994), Troughton and Stocker (1996), Byrne et al. (1998), Joer and Randolph (1998), Hamza and Leoni (1998), Littlechild et al. (2000), Hamza and Ibrahim (2002), Hamza (2003 a&b), Hamza (2015) and Shahien and El-Naggar (2015) showed that the shaft resistance of grouted piles could be nearly 1.5 to 5 times that of non-grouted piles."

Jan 1, 2017

By Steven M. Shope

An essential element of the Bureau of Mines electromagnetic location and communication system for trapped miners is a quantitative knowledge of the surface and above-surface electromagnetic fields created by an underground transmitter. The field solutions given in this report use approximations in which the displacement currents are negligible for low frequencies. The earth is represented by a homogeneous half-space model in which a dipole source is immersed. The vertical magnetic field equipotential contours at and above the surface are graphically mapped. The volumes of the regions bounded by these contours are directly related to the geometrical zones of signal detectability. Knowledge of the detectability zones will enable the proper search strategies to be developed for airborne detection of trapped miners.

Jan 1, 1983

By Roger Storry, Donald Bruce, Arnaud Hochart

"INTRODUCTIONThe Port of Miami Tunnel (POMT), designed and constructed by Bouygues Civil Works Florida between 2009 and 2014, was a Public Private Partnership between the Miami Access Tunnel Concessionaire, Florida Department of Transport, Miami-Dade County and the City of Miami. The project comprises dual 11.3m internal diameter, 1.27km long, twin lane road tunnels running between Watson and Dodge islands and under the main shipping channel in Biscayne Bay (Figure 1).The POMT was a unique project which embodied many technical firsts and involved the first large diameter tunnels constructed through Florida’s challenging sedimentary carbonate strata. At the outset, a comprehensive ground investigation was performed, using both conventional and less conventional investigation techniques, to characterise the highly heterogeneous ground conditions.The findings of the investigation had a major impact on the tunnelling methods, triggering a series of mitigation works to ensure that the tunnels could be excavated safely and effectively. The mitigations included modifications to the already designed Tunnel Boring Machine (TBM), to facilitate an innovative excavation process, and a unique grouting campaign (Storry et. al. 2013a). The project was completed and opened to traffic in August, 2014 and has significantly alleviated traffic congestion in Downtown Miami.GEOLOGICAL CONTEXTThe geological conditions at the project site consist of carbonate sediments which can be divided into distinct geologic units; the Miami Limestone Formation (Layers S3, S4), the Fort Thompson Formation (Layer S5), the Anastasia Formation (Layer S6), the Key Largo Formation (Layer S7) and the Tamiami Formation (Layer S8). Multiple changes in sea level over a relatively short geologic time scale have resulted in a heterogeneous profile consisting of interbedded sedimentary rocks and sediments, which vary widely, both vertically and laterally (Figure 2)."

Jan 1, 2016

By J. L. Jambor, T. C. Birkett, W. D. Sinclair

Abstract -The rare-earth elements (REE) form a significant part of the group of so-called "high­ technology" metals whose glamour has attracted both the scientific community and the mining industry. Despite this attraction, world production of REE declined abruptly in 1985 and only recently has begun to approach production levels of 1984. The decline in 1985 was primarily due to decreased demand for light REE used as catalysts in the production of lead-bearing gasoline. Incorporated within the current trend toward increased production of REE is an increasing demand for higher value elements such as yttrium and other members of the heavy REE group, and for specific REE rather than mixed products . The former demand has made some Canadian deposits and prospects economically attractive despite a surplus of REE reserves on a world scale. The chief attractions of Canadian deposits such as Strange Lake, Labrador-Quebec, Thor Lake, Northwest Territories, and Kipawa, Quebec, are that they are relatively rich in yttrium and other heavy REE compared to light REE, and that they offer a potential security of supply to counterbalance the rapidly escalating dominance of China in the world market.

Jan 1, 1992

By Edward H. Robie

THE registration badges gave out, there were not enough programs, the Pioneer Hotel's rooms were insufficient, and some hundred applicants for banquet tickets had to be turned down at the Institute's Regional Meeting in Tucson, Nov. 1-5. Minor inconveniences these, however, occasioned by the fact that, optimistic as they are in Arizona, about half again as many partook of the week's activities as were expected. For this, the local program committee can be blamed-both the technical and social features were too attractive in quantity and quality. Seriously speaking, though, the Institute has probably never had a more successful Regional Meeting than this one. It being the first that has been held in Arizona in 22 years, no effort was spared to make it the distinctive gathering that it was.

Jan 1, 1938

By H. C. Miller

The removal of the mud sheaths that are deposited against the faces of productive oil sands during rotary drilling is one of the important problems confronting operators, especially in semidepleted fields where formation pressures are low. Unless the mud sheaths behind the perforated oil strings and liners are removed and the sands exposed, oil cannot enter the wells. Consequently much oil that otherwise might be produced from low-pressure sands is trapped and never recovered. Various types of perforation washers, down swabs, and agitators are used at present for breaking down the mud sheaths and removing the disintegrated clay particles from wells after the perforated Wipes have been inserted. Mechanical methods for removing mud sheaths are :quite satisfactory, but prompted by the request of certain .operators in the California oil fields Bureau of Mines engineers have conducted a series of laboratory tests with the view of developing a chemical method for removing mud sheaths in oil wells that will be applicable to field conditions. This report describes the laboratory work and deals generally with a chemical method for removing the mud sheath, cake, or plaster deposited against the face of oil sands in drilling wells end in wells that, on being shut in temporarily during periods of overproduction of oil, are conditioned for the shutdown .period by filling the well opposite the producing formations with mud fluid. The method described in this report was devised in the San Francisco laboratory of the Bureau of Mines and, as far as the writers have been able to determine, differs from any chemical method ever used in actual wells. The method proposes to add a small amount of calcium carbonate (preferably pulverized limestone) to the mud fluids before they are introduced into the wells so that the resultant mud sheaths will be susceptible to disintegration by acid solutions when it is desired to expose the faces of the oil sands in the wells.

Jan 1, 1934

By Alex Maia do Nascimento

A capacidade de um determinado aço suportar as deformações ocorridas durante laminação sem fraturas ou trincas severas é denominada de ductilidade a quente, que é função de diversos parâmetros de processo dentre os quais: qualidade do tarugo, tipo de corte, ciclo térmico, temperatura de processo, layout do laminador, calibração, taxa de deformação e composição química. Diversos trabalhos abordam a ductilidade a quente enfatizando a influência isolada de uma variável como critério de qualidade como as conhecidas relações Mn/S e Ni/Cu através da determinação de valores mínimos. A globalização tem sido responsável pela crescente competitividade entre as siderúrgicas que, para se manterem competitivas no mercado, têm que buscar inovações, quebras de paradigmas, estratégias ousadas e assumir riscos. No presente trabalho realizou-se uma avaliação de risco com base no princípio ALARP (As Low As Reasonable Practical) através da análise conjunta das principais variáveis de processo responsáveis pela perda de ductilidade a quente de um aço utilizado para produção de barras de aço CA-50, objetivando-se uma solução otimizada de menor custo garantindo a competitividade e sustentabilidade da cadeia produtiva.

Aug 17, 2017

By E. Henderson, L. K. Daneshmend

Drawpoint control is critical in determining the cutoff point for load-haul-dump mucking operations to minimize dilution. It is also necessary to ensure even mucking distribution and to prevent possible hang-up of material within a stope. A prototype production monitoring and reporting system has been developed for load-haul-dump operations in under-ground mines. The system generates accurate and timely information regarding mucked tonnages and drawpoint and ore/waste pass utilization. The monitoring system integrates a PLC-based load weighing system with a radio frequency identification (RFID) system for locating the vehicle. The system records the identification and time of entry and exit of each draw-point and ore/waste pass visited during a shift, as well as the weight of each bucket load. A trial of the system was conducted at the CAN-MET Experimental Mine near Val d’Or, Quebec. The monitoring and reporting system functioned as designed, with the exception that the maximum read range of the RFID tags under dynamic conditions was found to be a limitation. RFID systems with greater range capabilities have been identified for a second generation system. The system is the first of its type in North America to demonstrate that RFID tagscan be successfully applied to locate trackless underground equipment. Because of their ability to locate equipment and personnel within underground mines, RFID systems should be considered a key technology for future mine information and process control systems.

Jan 1, 1996

By D D. Deacon

A brief description is given of the requirements which No. 4 Shaft has been designed to meet and of the methods by which two-stage winding of rock has been accommodated in a single shaft sunk to a depth of 7,421 ft. This is followed by a consideration of the factors which led to the decision to sink the shaft as rapidly as possible. Introduction T HE No. 4 Shaft of Hartebeest-fontein Gold Mining Company, Ltd., has been sited to serve the deep southern area of the mine, some 1,500 claims in extent, between the elevations of 6,250 and 7,300 ft. below surface. From this area, some two-thirds of the mine production will ultimately be obtained. Above the 6,-250-ft. elevation, an existing shaft hoisting system, situated adjacent to the reduction plant, is of adequate capacity to cater for all ore hoisted to surface for milling. No. 4 Shaft will therefore be required to provide downcast ventilation of 1,000,000 c.f.m., together with surface hoisting facilities for men, material and development rock and underground hoisting

Jan 1, 1965

By G. M. Ritcey

The recovery of copper from low-grade solutions res ulting from dump leaching is well known, whereas the recovery from highly concentrated copper solutions has not been practiced. This paper discusses the use of Ashland Chemical's Kelex 100, a substituted quinoline, for the recovery of copper from solutions resulting from leaching copper-nickel concentrates. A flow sheet is described, and an economic comparison shows Kelex 100 to be superior to either the LIX 64N or LIX 70 reagents of General Mills for the recovery of copper.

Jan 1, 1973

By G. Q. Zhou, H. C. Liang, X. D. Zhao

"This study describes the strain behavior in vertical shaft lining (VSL) embedded in thick soil deposits and its application in assessment of concrete deterioration. The observed strain in VSL continuously decreased companied by a sinusoidal fluctuation due to the influences derived from negative skin friction (NSF) and temperature. The increase in strain increment between peak and trough at each year and compressive strain level as the servicing time continued and VSL depth increased implies that the concrete strength was attenuated, and this attenuation was significantly dependent on the existing compressive strain level in VSL. The reliability of the proposed approach was validated by Schmidt Hammer Technique (SHT) – based concrete strength, and is applicable in concrete assessment and then fracturing prediction of VLSs in thick soil deposits.Concrete strength, Field monitoring, Strain behavior, Vertical shaft liningINTRODUCTIONOver 100 VSLs in Southeastern China subjected to an unpredictable fracturing as shown in Figure1, and there are over 1,000 VSLs embedded in thick alluvium su?ering from challenges of damaging and potential fracturing (Cheng, Yang, Zhou, Li, & Hu, 1993; Zhou, Cui, Lv, Huang, & Chen, 1999; Li & Li,2005). Therefore, a reliable assessment of these VSLs is significant to the normal servicing of mine shafts and the recycle of underground space when these mine shafts were closed.The continuous increasing of NSF induced by the drainage of water–saturated deposits well interpreted such extensive fracturing phenomenon, and it is universally regarded as the governing indicator to determine the VSL stabilization (Cheng et al., 1993; Zhou et al., 1999). Based on this recognition, the fracturing prediction and VSL strengthening according to the field monitoring on hydrogeological characteristics, servicing environments, and mechanical behaviors of VSL were carried out (Zhao, Zhou, Zhong, Zhu, & Liang, 2009; Liang et al., 2009; Xie, Lv, & Wu, 2014). As known, the compressive strain level in VSL and the in–situ strength of VSL concrete were the main factors to perform such fracturing prediction. However, the existing studies in literatures were limited to the strain accumulating or releasing behaviors (Zhao, Zhou, Zhao, Kuang, & Hu, 2017), and lack of considering the VSL concrete strength and its attenuation. In this reported study, the in–situ monitoring data on the strain in typical VSLs and the VSL elevations between 2004 and 2014 were initially analyzed. Then, an observed strain behaviors–based approach was developed to quantitatively evaluate the VSL concrete deterioration."

Jan 1, 2019

By C. Blawert

The corrosion properties of the skin and the bulk of semi-solid processed and high pressure die cast AZ91 alloy were studied in 5% NaCI solution by (a) analysing the corrosion morphology, (b) measuring electrochemical polarization curves, (c) performing electrochemical impedance spectroscopic measurements, and (d) immersion tests at constant pH-values. Using XRD, LM, SEM and EDX to evaluate the microstructure of skin and bulk specimens, the corrosion results were related to the microstructures of the particular alloys. However, microstructure and corrosion performance were found to be similar for both production processes, and only slight but distinct differences were found. Generally, the skin corrosion properties are inferior to those of the bulk, with the exception of the high pressure die cast AZ91 alloy, where the finer microstructure of the skin layer exhibits a better performance as showed by impedance studies and confirmed in long term immersion tests.

Jan 1, 2004