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By H Kurth, L Balzan

The potential for bulk diversion was identified and quickly implemented following the development of bulk sensing technologies applied to conveyed flows. In the early 1980s real time analysis of ash in coal was intended to improve the understanding and control of quality variability. By the end of the 1980s approximately 5% of coal analysers installed were being utilised for bulk sorting; diverting flows to create stockpiles to improve blending flexibility and boiler feed consistency, diverting waste material, or bypassing the beneficiation process when the coal met product quality criteria. In the 1990s bulk sensing and sorting utilising natural gamma detection was applied to conveyed waste in gold-uranium mineralisation and allowed ore to be recovered and processed that would otherwise have been discarded. Further applications developed in the iron ore sector where product quality ore could be diverted to bypass beneficiation and save significant unnecessary processing costs and improve recovery by avoiding process inefficiency losses. Plant capacity was freed up to be utilised by material that required processing. Similar benefits became evident in the phosphate industry and in base metals where multi-elemental analysis using Prompt Gamma Neutron Activation Analysis provides ideal opportunities to representatively measure 30 second conveyed increments at high accuracies. This has been successfully adopted in copper, nickel, platinum and lead-zinc to improve waste removal after primary crushing to eliminate unnecessary expense and improve plant efficiency. The benefits include increased output from existing operating capacity, significant reductions in consumable costs and generation of fewer detrimental waste streams. The paper outlines the technologies and discusses case studies covering the above commodities, demonstrating the immense value that representative real time measurement of conveyed flows can create. Measurement data concurrently provides multiple benefits in operational performance besides sorting, through ore reconciliation, ore blending, feedforward control and metal accounting, adding further value.

Nov 10, 2020

By L. A. Matthews

The embrittlement of the Ti-6Al-4V alloy by hydrogen dosing at elevated temperature has been investigated. Metal coupons were subjected to isothermal treatments in a partial hydrogen atmosphere in the temperature range from 650ºC?950ºC and the degree of embrittlement after treatment was determined by drop-weight impact testing. Embrittlement was found to be inversely related to reaction temperature as a result of the combined effects of greater hydrogen absorption and titanium hydride precipitation at the lower isothermal temperatures. Keywords Titanium, hydrogen embrittlement, impact energy

Jan 1, 2011

By C. W. Morris

This Final Report describes the major technical activities that were accomplished to produce a comprehensive continuous miner training system (CMTS) for coal industry utilization. The primary product of this program was a continuous miner part-task trainer. It is composed of an interactive computer graphics system combined with the operating controls of a continuous mining machine mounted in a simulated cab. The cab contains an audio system for reproducing continuous miner operational sounds. The trainer is supplemented with a complete set of cognitive materials that provide instruction in the operation, safety and health of continuous miner operations. A complete summary of the field test and evaluation of the CMTS is provided along with a set of recommendations for further training program refinements, expansions, and utilization.

Jan 1, 1982

By J. F. Neill, O&apos

[The Cartersville mining district is in Bartow County, Ga., about 40 miles northwest of Atlanta. Barite, limonite, ocher, amber, hematite, and, manganese oxide ores have been produced from the strict since about 1840. In the search for a possible source of manganese ore, Bureau of Mines engineers made a preliminary study of the district from September 1950 to January 1951. During this study 139 deposits were examined, and many mineral exposures were sampled. Manganese mineralization occurs as fine oxide and concretionary pellets in residual clays, as fine oxides in umberous clay, in brown-iron deposits, and in a limited quantity in mud ponds and Jig-tailing piles. The future supply of ferrograde manganese ore from the district, using current mining and benefication methods, appears limited to the recovery of the hard manganese ores deposits. Rough estimates indicate a reserve of manganese-bearing clays of about 8,000,000 long tons. This type of deposit has been extensively exploited and the larger deposits mined out to depths of from 50 to 200 feet. The remainder of these deposits are low grade, are covered with deep layers of colluvium, or lie below the ground-water table. Any future production from this source will require systematic prospecting, improved concentration, and an increase in the price of concentrate.]

Jan 1, 1954

By W. C. Maurer

A study of the mechanics of shear failure of rock under pressure has been made. The transition from brittle to ductile failure occurs when the friction along the fracture surfaces exceeds the shear strength of the rock. A machine has been developed for measuring both the shear strength of rock and the friction along rock fracture surfaces. In this shear machine, the fractures are forced along definite planes; as a result, the rock is stronger than in compression tests where the fractures choose the weakest paths through the specimens. Friction is composed of several forces: (1) the forces to slide irregulurities on surfaces over each other; (2) forces to shear some of these irregularities; (3) molecular attractions across the fractures; and (4) forces required to break bonds resulting from melting and welding at the tips of irregularities on the surfaces. Friction along rock fracture surfaces is not proportional to contact pressure as usually assumed; instead, it increases as the contact pressure raised to the 0.4 to 0.8 power. INTRODUCTION It is difficult to produce tensile stresses under the high compressive stresses present in the earth; therefore, in deep drilling and geological faulting, shear failure predominates. This shear failure mechanism is complicated because rock is a heterogeneous material containing pore spaces, microfractures, elastic discontinuities and other imperfections. A study of shear failure of rock under pressure has been made to obtain a better understanding of this complex mechanism. A machine has been developed and used to measure the shear strength of rock and friction along sheared surfaces. This machine has certain advantages over the compression test — shear properties can be measured under low normal stresses and shear stress and normal stress can be varied independently. The first part of this paper is a description of shear failure of rock under pressure. The role of shear strength and friction along fracture surfaces in the shear failure mechanism will be discussed. The second part consists of a description of the shear machine and a discussion of the shear strength and friction data obtained using this machine. It will be shown that shear strength depends upon the size of the stressed zone, and that friction does not increase linearly with contact pressure as usually assumed. Attempts are made to relate some of the new concepts to tectonic failure and to dril ling. SHEAR FAILURE IN ROCK TRIAXIAL TESTS The shear failure mechanism is illustrated by the triaxial test shown in Fig. 1. In this test, a cylindrical rock specimen is subjected to a confining pressure, PC, and an axial pressure, pa. These external pressures produce normal a and shear T stresses on inclined planes within the specimen equal to1 where 0 is the angle between the specimen axis and a normal to the inclined plane. Fig. 2 shows how triaxial specimens deform as the axial pressure is increased. The pressure is

Jan 1, 1966

By Ellsworth R. Spencer

An assessment of U.S. western hardrock miners? noise exposures was conducted as part of a multi-year National Institute for Occupational Safety and Health (NIOSH) survey of noise exposures in each sector of the mining industry. Noise from selected mining equipment and operator noise exposures were measured, analyzed and tabulated for dissemination to the participating sites and are being used to direct NIOSH research and interventions to address the greatest noise hazards. Eighty-two noise dosimeter measurements were obtained, along with time-motion studies as the miners operated hardrock mining machines. Of the operators, 96% had daily noise doses that exceeded the U.S. Mine Safety and Health Administration?s (MSHA) permissible exposure level. The average gold miner dosages while operating the following equipment were: haul trucks - 261%, load-haul-dumps (LHDs) - 235%, single boom drills - 221%, bolters - 214% and dual boom drills - 163%. The worst exposure level was a silver miner with a daily dose of 873%. Time-motion data showed that this miner?s exposure accumulated most rapidly while operating a jackleg drill. These results will be used to help prioritize noise control development by NIOSH and other partners.

Jan 3, 2010

By F. Rosenblum, K. E. Water, J. A. Finch, S. Moon, Y. H. Tan

Previous work has shown that sulphide self-heating occurs in three distinct stages referred to as Stage A, Stage B and Stage C. In this paper the focus is on the transition from Stage A to Stage B, which occurs at ca. 100OC. Background literature hints that the transition corresponds to the transformation of the rhombic form of elemental sulphur to the more reactive monoclinic form that occurs at 96OC. A test apparatus is modified for adiabatic heating to track the transition. The results support this transformation of sulphur as being key to the transition, and the transition temperature is thus modified to 96OC. Variations in a sample’s response under adiabatic conditions are observed and possible reasons are discussed. Testing in adiabatic mode provides new insights into the sulphide self-heating process that complement the test designed to identify propensity to self-heat. Keywords: Self-heating; Stage A/Stage B; transition; rhombic/monoclinic elemental sulphur; adiabatic heating

Jan 1, 2020

By Angelina Anani, Nathalie Risso, Carlos Olmos de Aguilera

The traditional approach to safety clearance monitoring and proper PPE usage in underground mines is time-consuming, costly, and susceptible to negligence. However, automated real-time monitoring can be implemented using computer vision-based approaches. This study aims to develop a system that provides timely information based on the automatic detection of proper PPE use and safety clearance in underground mines. Deep learning and a decentralized computing structure between the cloud and sensing devices (fog technology) are used. We hypothesize that a camera-based system can provide near real-time assessment of proper PPE use and verified clearance to access restricted areas in underground mines.

Jun 25, 2023

By F. E. ROGERS

CUSHMAN TUNNEL No. 2 is adjacent to the Hood Canal, near potlatch, Wash. It is 17 ft. inside .diameter, about 13,000 ft., or two and one- half, miles in length, and is a part of the second unit of the Cushman power project. It connects Cushman ' Dam No. 2 and the penstocks that lead to the power house on the beach about 400 ft. vertically below the outlet of the tunnel. One shaft, 190 ft. deep, and two adits between 300 and 400 ft. long, were provided to speed up driving operations. his arrangement gave 6 working headings, which were operated 24 hr. daily. The shaft provided a manway, cageway, and skipway.

Jan 1, 1931

By Leandro de Arruda Santos, Lorena Isabela de Oliveira Ribeiro, Jéssica Dornelas Silva, Pedro Damas Resende, João Victor Lucas Amim, Suzanny Cristina Soares Martins, Vicente Tadeu Lopes Buono

O objetivo do presente estudo foi avaliar a resistência à fadiga de duas ligas de NiTi diferentes sob condições de teste controladas por deformação a 25°C por meio de testes de fadiga por flexão rotativa. Além disso, as propriedades mecânicas, térmicas e estruturais dos fios foram caracterizadas por ensaios de DSC, DRX, MEV/EDS e tração. Os resultados revelaram que ambos os materiais são superelásticos à temperatura ambiente e, portanto apresentaram composição basicamente austenítica de sua matriz. Os resultados de ensaio de tração são condizentes com a caracterização térmica e estrutural, pois os materiais apresentam recuperação total de forma após ciclos de carga e descarga em tração. Ambos os materiais são ricos em titânio, um deles apresenta camada de óxido superficial enquanto o outro apresenta acabamento superficial. Apesar das propriedades similares a amostra 1 apresentou média de 77 ciclos até a falha, enquanto a amostra 2 resistiu a 1827 ciclos..

Oct 25, 2019

By Oliver C. Fursman

The Bureau of Mines undertook this investigation in order to determine the feasibility of producing commercially acceptable alumina and iron by application of the Pedersen process to high-silica, high-titania, ferruginous bauxites of the Pacific Northwest. Calcium aluminate slags were produced by smelting bauxite with coke and lime in an electric-arc furnace. Over 90 percent of the total alumina can be extracted by sodium carbonate solution from slags of properly controlled ternary-phase composition (CaO-Al203-SiO2) that are cooled slowly enough to permit adequate crystallization of the 2CaO-SiO2 and the calcium aluminate compounds. Most of the iron charged was recovered in the regulus; the slag contained about 2 percent iron (as iron oxide), regardless of smelting time.

Jan 1, 1968

By Kihong Park, Matthews C. Habjan, Arthur L. Miller

New Mining Safety and Health Administration (MSHA) regulations limit the mass concentration of airborne diesel particulate matter (DPM) or, more specifically, the concentration of elemental carbon (EC), in underground mines. The mine operators are responding by introducing a variety of controls to reduce DPM in the mines, potentially including the evaluation of new maintenance procedures to reduce underground mine vehicle emissions. There is currently a lack of an inexpensive and dependable method to directly measure the DPM concentration emitted from the vehicle tailpipe. To that end, this work demonstrated a simple field portable method for estimating the mass concentration of elemental carbon exiting the tailpipe of a diesel engine using a direct reading photometer. Simultaneous measurements of tailpipe exhaust were made with a Thermo Electron Personal DataRAM 1200 photometer (particulate mass concentration based on light scattering) and by analyzing PM2.5 and PM1.0 samples collected on quartz fiber filters using the National Institute of Occupational Safety and Health (NIOSH) method 5040 (mass concentration of EC via thermal-optical method). Results indicate surprisingly good correlation (R2 ) 0.97) of the two methods when the data are adjusted for relative humidity (RH) and corrected using an empirically generated calibration factor. Although preliminary, it may be possible to implement this method in maintenance shops to monitor emission trends and to compare emissions of various vehicles in a fleet. Such data will be useful for fleet planning to meet new air quality standards.

The Department of Health and Human Services (HHS), National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), with the assistance of cooperating underground mining operations and state agencies, has conducted research exploring devices and technologies that could be used to assist miners navigating through smoke and dust resulting from a fire or explosion. Recent events in mines confirm that smoke and dust can enter and contaminate mine escapeways creating an atmosphere with severely reduced visibility. This reduced visibility results in substantially increased escape times, possible disorientation or confusion, and increased stress levels, and may prevent evacuation altogether. Tools or devices that assist miners in navigating through smoke-filled areas void of lifelines could make the difference in successful escape from the mine. This paper presents the results of OMSHR research to identify and evaluate tools and devices that could provide meaningful information to evacuating miners in areas with limited visibility and without the benefit of a lifeline.

Jan 1, 2011

By Michael W. Neill, O&apos

The engineering profession generally does not accept vibro-driven piles as bearing piles unless their capacities can be verified by restriking with an impact hammer, which significantly reduces the economic benefits of vibratory driving. In part, the concern for capacity development in piles driven by vibration arises out of observations that vibro-driven piles do not develop capacities equivalent to those driven by impact (e. g., Mosher, 1987). Nonetheless, if capacities are predictable, vibratory installation may be more cost effective than installation by impact, due to savings in time of installation, even if capacities are lower than those of impact-driven piles. Throughout the past few decades, a number of attempts have been made to develop capacity prediction methods for vibro-driven piles, mostly along the same lines as methods for impact-driven piles. That is, (1) totally empirical formulae, (2) power balance / power transfer formulae, and (3) "time domain-nonlinear" (TDN) computational procedures such as the wave equation. Some of the formulae have been based partly on field experience, but the majority have been developed from simple theoretical models with parameters evaluated from laboratory studies. Neither these formulae nor the TDN solutions have been systematically checked (or modified) by recording appropriate field data over a variety of site

Jan 1, 1989

By Reno H. Sales

Our colleagues cannot in the future earn reputations and medals for achievements in milling and smelting ore and for successful management of mining companies, if some one doesn't keep finding and mining the ore to mill and smelt and to provide the basis for the good management. Good ore seems sometimes to be quite helpful to good management, and good ore is not as easy to find as it used to be. And there are still more reasons, why—when this honor had been decided upon and named for Mr. Daniel C. Jackling—it should be initially conferred on Reno H. Sales. . The terms of reference of the award are that it should be conferred upon an individual working in the fields of mining, geology, geophysics, who has made an outstanding contribution to the progress of technology in one or more of those fields. And in this initial year (the earlier years are the easiest) just that was done. I think I could get away with it amongst the old-timers of my generation if I say that this time they made the award to the individual, who made the outstanding contribution. But, as Al Smith used to say, "Let's look at the record." Really, the record is mixed up a little with extra-lateral litigation—the old-time "apex cases" under Section 2322 of the Revised Statutes. Reno Sales doesn't like such litigation, but there is little question that the urgency, generated by conflicting claims of intra-limital and extra-lateral rights, and consequent necessity for committing to records and maps the complications of Butte structure, did advance—and by several years—the first continuous, accurate, systematic, and scientific portrayal of the geological and mineralogical details of what is, after all, the most important and the most complicated copper district—at least in North America. Prior to Sales' time, some of the most eminent of geologists often waived details. One geologist took the judge to the window to show him the Rarus fault going through a notch in the Continental Divide. The entertaining testimony in the Bluebird litigation was as perfect in literary style as it was innocent of the criteria by which faulting and lack of continuity of vein structure are now recognized. At any rate, this need for an accurate record of structure was in the background—to whatever extent it was, or was not, the etiological agent—for formation of the Geological Department of the Amalgamated Copper Co. in and about the year 1900. Charles W. Goodale was at that time the head of the Boston & Montana, and John D. Ryan succeeded William Scallon as the president of Anaconda Copper Mining Co. in 1905. Horace V. Winchell, for years a specialist in extra-lateral litigation, was perhaps the man who at that date had the vision, the persuasive weight with the management, and the willingness to defend the idea of large current expenditures (as then viewed) for a complete and sys-

Jan 1, 1955

By Hatch, A. Reple, W Valery

The mining industry is facing declining feed grades which require the mining and processing of larger volumes of material per tonne of product. Pre-concentration aims to remove barren material at as coarse a particle size and as early in the process as possible to reduce processing costs, energy consumption, water losses, and greenhouse gas emissions while increasing production and profitability. This may be achieved using bulk ore sorting—the separation of barren gangue from a fully loaded conveyor belt based on the grade as measured or inferred from a sensor. This paper evaluates the technical and economic viability of bulk ore sorting for the PanAust Phu Kham copper deposit in Lao PDR. Bulk ore sorting technology is described briefly along with discussion of appropriate sensor and diversion systems for the Phu Kham operation. To evaluate the economic implications, the actual mined material and costs from 2014 were used as the base-case. Sampling data was not available; therefore, the ore grade variability that would feed a bulk ore sorter was estimated using geo-statistical tools based on mine grade control data. The sorter performance when treating this material was simulated considering the accuracy of the sensor measurement and errors associated with material diversion. The impact on inferred cash flow was estimated for several different scenarios considering the additional costs for sorter operation and reject handling. The evaluation demonstrated that bulk ore sorting at Phu Kham has the potential to increase the amount of metal in product and/or reduce processing plant throughput (and costs) to improve the annual inferred cash flow for the conditions investigated. The sorter is the gatekeeper – only material above the cut-off grade (value-adding) reports to the processing plant; no waste dilutes the feed. Likewise, above cutoff grade material is not lost to waste; preventing lost revenue.

Jan 1, 2016

By I. Sedat Buyuksagis, Jamal Rostami, Ali Naeimipour

"Improving the safety of underground openings and optimizing ground support systems requires reliable ground characterization. This includes understanding the joints, discontinuities, and rock strength. Joint information can be obtained from borehole cameras, but measuring in-situ rock strength is very difficult. Use of borehole probes can be an ideal and efficient way to meet this requirement. This paper discusses the development of the Rock Strength Borehole Probe (RSBP) and presents the preliminary laboratory/field test. This device can be an accurate, flexible, quick, non-disruptive, and cost-effective alternative to estimate the rock strength inside boreholes in underground mines and tunnels. In addition, the scratch testing procedure in the laboratory by means of a newly developed miniature linear cutting machine is explained. Based on the results of these tests, two equations are developed to estimate the uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) of the sedimentary/metamorphic rocks. These equations, are based on testing 27 different sedimentary, igneous, and metamorphic rocks by full-scale scratch tests, including the cutting tests by a miniature disc. The results show a good correlation between the normal force and the compressive strength of sedimentary rock if the depth of the scratch is known. No significant correlation was observed for igneous rocks, due to the impacts of grain size.INTRODUCTIONEstimated rock mass properties are essential input for geomechanical studies and stability analysis for any structure constructed in or with rock. The availability of geological information is the crucial component of rock mass classification. One of the important parameters in evaluating rock mass properties is the intact rock strength. This parameter is usually measured by testing the core samples, obtained from exploration boreholes. These samples are subsequently tested in geomechanics laboratories. The test results offer limited information about the rock at the few boring locations despite all the efforts and costs. In addition, these results may not necessarily be representative of the behavior of the rock in the field as the test cannot provide the insitu condition of the ground."

Jan 1, 2016

By J. P. Powell

Since the beginning of waterflooding in the Midcontinent area, the Bureau of Mines has published many reports3-6/ describing in detail the results obtained on individual waterflooding projects in the area. These are intended as guides for operators in the selection of well-spacing, water-treating, and other techniques, as well as an indication of the results being obtained in waterflooding in various areas, fields, and horizons. In addition, Bureau personnel has arranged a tour of selected waterflooding projects each year for the past several years so that actual operating conditions may be observed and an additional opportunity provided for exchanging information. Each of these tours has been supplemented by a published

Jan 1, 1959

By Agnes Y. Lee

As part of the U.S. Bureau of Mines program to improve base metal leach systems, pressure leaching of galena (PbS) concentrates in fluosilicic acid (H2SiF6) solution was investigated. Lead extraction was 93 pct when PbS was pressure leached in H2SiF6 at 95° C with 2OO-psig O2 pressure for 40 min, using ferric nitrate [Fe(N03)3] as a catalyst. The effects of several catalysts, O2 pressure, time, and acid concentration on leaching were determined. The purified leach solution was electrowon to recover high-purity Pb metal. The H2SiF6 used in leaching and electrowinning can be recycled continuously. A flow diagram was proposed based on this investigation. Elemental sulfur (SO) was recovered from the leach residue by solvent extraction. A method was also developed for treating the flnal residue to segregate the important byproduct elements such as Ag, Cu, and Zn and enable their recovery by standard commercial processes.

Jan 1, 1990

By C. A. Heiland

NOT only has the demonstration of progress in all fields of science been characteristic of the Chicago "Century of Progress," but the manner in which the fundamentals of these sciences have been displayed captivated the visitor's eye and ear at the same time. The average individual is interested most in progress which concerns his every-day life. He is fairly well educated in medicine, biology and certain aspects of physics. But how raw materials and chiefly minerals occur, how they are located, taken out of the ground and refined, is something which appears to be more remote from the every-day line of interest, and about which, therefore, the public knows comparatively little. This is particularly true of the oil industry, although it ranks in size second only to agriculture in the United States. In appreciation of the tremendous educational value which a complete exhibit on all phases of the mineral industries would have, both mining and metallurgical as well as oil inter¬ests took steps early to make these exhibits at Chicago a reality. The board of directors of the A. I. M. E. authorized an advisory committee to the Museum of Science and Industry early in 1932. It is divided into four subcommittees - for geology and petroleum, for metal mining, for coal mining, and for metallurgy respectively. The entire committee held its first meeting in Chicago on April 11 and 12, 1932, to advise with the Museum's officials and experts about the most advantageous arrangement of the minerals industries' and geology exhibits.

Jan 1, 1933