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By R. K. Paramguru, K. Srinivasa Rao

This paper describes a new approach for examining the kinetics and mechanism of zinc dissolution from sphalerite concentrate in acidic ferric sulfate solution in the presence of manganese dioxide. A literature search was performed to access the possible action of the two oxidizing agents, i.e., ferric ion and manganese dioxide. The possibility of galvanic coupling between ZnS and MnO2 and the cyclic action of the redox couple, Fe2+/Fe3+, on these two minerals were theoretically examined based on corrosion principles. Expressions for the mixed potential (Em) and the mixed current (im) were derived for the relevant corrosion and galvanic couples. Leaching experiments were conducted to establish which of the above phenomena is operative during leaching. The results indicated that the dissolution mostly occurs by the action of ferric ion on ins producing ferrous ions. The presence of MnO2 enables a quick conversion of ferrous to ferric, which maintains the rate of in dissolution. The process has promising features for commercial exploitation.

Jan 1, 1999

The need for geological control in orebody estimation and modelling is self- evident to geologists and mining engineers engaged in practical day-to-day estimation. It is only fairly recently, however, that attempts have been made to incorporate explicitly such requirements into published accounts of geostatistical estimation; see, for example, Dowd and Scott (1982, 19841, Rendu and Readdy (1982), Dagbert et al. (1984), Dowd (1984), Benest and Winter (1984). In practice, many geological controls in automatic or semi-automatic estimation and modelling are essentially geometrical controls. The aim of this paper is to present two techniques for geological/geometrical control. Whilst the applications are new, neither technique is entirely original and both have been adapted from other fields and sources. Both techniques are, in some sense, types of estimators and/or interpolators of shapes. The first is a method for fitting spline surfaces to control orebody boundary estimation and to unroll orebodies. The second is an application of Minkowski addition to interpolate shapes such as orebody outlines or stope boundaries and to control estimations.

Jan 1, 1986

By Dewa Putu Agus Sudarmaja, Widi Astuti, Januarti Jaya Eka Putri, Yayat Iman Supriyatna, Himawan Tri Bayu Murti Petrus, Siti Nurul Aisyiyah Jenie, Ferian Anggara, Anisa Maulidia, Vincent Sutresno Hadi Sujoto, Sutijan, Wayan Warmada

With the rapid development of renewable energy technology, such as electricity reserves to store energy for electric and battery-electric vehicles, environmentally friendly energy sources are expected to continue to be tapped to meet mobility and stationary energy needs. Lithium is the most attractive candidate for energy storage development. The presence of lithium in the Sidoarjo mud in Indonesia makes it interesting for use as an alternative source of raw material. In this research work, sulfuric acid was used as a solvent, and hydrogen peroxide as an oxidation agent. Lithium recovery was studied with a leaching process at various temperatures (30, 45 and 60 °C) and sulfuric acid concentrations (0.5, 1, 2, 3, 4 and 6 mol/L). Increases in temperature, sulfuric acid concentration and hydrogen peroxide concentration were found to directly affect the lithium recovery. An increase in sulfuric acid concentration is directly proportional to the recovery of lithium in the solution. Optimum conditions were obtained at a sulfuric acid concentration of 6 mol/L and temperature of 60 °C. The shrinking core model was used to study leaching kinetics, and ash layer diffusion acted as a rate-controlling process. The activation energy of the leaching process was found to be 38.90 kJ/mol.

Jun 1, 2024

By D. G. Klaren

Self-cleaning fluidized bed heat exchangers are conquering the world for reason that they are able to solve any severe fouling problem in indirect heat transfer due to the circulation of cleaning particles through the tubes of vertical shell and tube exchangers. In most cases, these particles consist of chopped metal wire. Moreover, self-cleaning fluidized bed heat exchangers perform with excellent heat transfer at very low liquid velocities, which enables completely new designs of conventional shell and tube configurations. This article explains the principle and application of this self-cleaning heat exchange technology and also pays attention to an actual case of a revamp of the severely fouling exchangers of a conventional multi-effect evaporator into a self-cleaning configuration. Possibilities for the revamp of conventional exchangers suffering from massive and very hard scale deposits are found in a variety of metallurgical processes, such as: The refining of nickel, the production of alumina from bauxite and many others.

Jan 1, 2003

By Min Chen, Qinghua Liang, Weishan Yan, Yuan Feng, Shigang Wang

Various coal mine robots (CMRs) and unmanned aerial vehicles (UAVs) are implemented to explore unknown mines for improving the safety and efficiency of mining. It is challenging for CMRs and UAVs to achieve accurate positioning due to the absence of the Global Positioning System (GPS), poor lighting conditions, and similar geometric features in complex mine scenes. LiDAR-based localization and mapping methods are more accurate than others, while long-time running in large-scale scenarios will introduce nonnegligible cumulative errors. This study presents a semantic-aided Li- DAR simultaneous localization and mapping (SLAM) with loop closure, which leverages the uniqueness of mine intersection structure to establish stable semantic loop closure. Specifically, we propose a semantic intersection descriptor of translation and rotation invariance, which encodes 3D point clouds of the same intersection from different positions and viewpoints into a unified image. By using the semantic descriptor, we can construct a constant loop constraint when the same intersection is revisited from different directions to reduce cumulative drift. We provide experimental validation using large data sets collected in two large underground mines, namely, a simulated Edgar mine deployed in ROS Gazebo and a public underground mine data set provided by ETH. Experimental results show that the proposed method has higher localization accuracy and outperforms the existing LiDAR-based SLAM strategies.

Feb 1, 2024

By Thomas J. Neil, O&apos

Most analysts find that progress has been evolutionary in any technologic field. To be sure, a few discrete breakthroughs can usually be identified, but viewed in its entirety, the curve of technologic progress over time tends to be relatively smooth with few discontinuities. Even in those cases where a major scientific discovery is achieved, the rate of technologic progress is limited by the often surprisingly slow rate of commercializing the concept into usable products. Whereas discovery and invention tend to be discrete events, technical innovation is often a painfully slow process. In spite of overall gradual change, technologic progress in most fields, when viewed in retrospect, tends to reveal certain relatively homogeneous periods where little change is evident, separated by episodes of accelerated progress. Thus, open-pit mining over the past century has changed from predominately train haulage to truck haulage and is now experiencing a major increase in belt haulage. Ore reserve estimation is another field that fits the same pattern, and the history of mine evaluation lends itself to a similar analysis. Evaluating mine investment opportunities is a fascinating aspect of mining. The unique set of risks inherent to every mining project is particularly intriguing. Geologic risks are most obvious, since faulty ore grade and tonnage estimates are among the leading causes of mine failures. Wide swine's in mineral commodity prices are usually cited as another major risk in mining. Because any ore deposit is a finite resource and the miner has limited discretion in selecting a mining sequence, mines are generally at the mercy of notoriously fickle commodity markets. There is a tendency for many mine investment analysts to feel that mineral market uncertainties are unprecedented in severity. Of course, prices in other markets rise and fall also-in some cases as precipitously as with minerals. However, two other mining characteristics tend to compound this marketing risk. First, the preproduction development period for a new mine is characteristically long. Under extremely favorable conditions, a significant mine may be developed in as little as two years, but the norm is four to six years or more. Second, mining is among the most capital intensive industries, consistently ranking near the top among all industrial sectors in assets per employee, and near the bottom in annual sales dollars per dollar of assets. Thus, mine investors typically have large sums invested for a long time before the outcome of the venture is determined by notoriously unpredictable markets. This is not a business for the faint of heart, and the importance of sound investment decision making is obvious. The high risk and technical complexity of mining operations have combined to require greater attention to financial evaluation by mining engineers than by most engineers in other specialties. Nearly all early mining engineering textbooks dealt with problems in mine valuation in a detailed manner; and, today, the sophistication of capital investment analysis is high in the mineral industries. Traditional Mine Valuation Methods Although some evaluation process has no doubt accompanied nearly every mine development throughout history, a formalized quantitative approach first emerged in the last half of the 19th century with the establishment of academic programs in mining engineering. The philosophy and approach to mine valuation that evolved at this time were, with periodic minor refinements, considered the standard for nearly a century. Only after 1960 did major changes begin to occur. The traditional approach to mine valuation reflected the investment community's historic attitudes toward risk. Mines were generally considered too risky for debt financing, and virtually every new mine was financed from internally generated funds or new equity subscriptions. The investment evaluation methods that evolved focused on mining's higher risk relative to other

Jan 11, 1982

By Emily Wortman-Wunder

As the 2011 president of the Society for Mining, Metallurgy, and Exploration, Inc., I am pleased to present the 2011 issue of the Transactions of the Society for Mining, Metallurgy, and Exploration, Vol. 330. A significant portion of the contribution that we as a professional society make is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable the transfer of technology. Communication within the mining community is the key to a successful society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, PA, that resulted in the founding of AIME; those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume fulfills that pledge. The 2011 Transactions is the second Transactions to take advantage of new publication technologies. It appears solely in electronic format. The decision to go to an all-digital format for this longstanding publication was a difficult one, but one which will better serve the mining community. Based on the feedback from the 2010 Transactions in e-book format, I believe that the transition to the all-digital format was the proper decision. The 2011 Transactions contain some of the most interesting research from the past year, including a 10-year profile of roof and rib fall trends from the National Institute of Occupational Safety and Health (NIOSH) and a new cross-disciplinary application of the tools of epidemiology to assess and mitigate risk in coal mines . This 2011 Transactions comprise of a total of 82 technical papers (626 pages including index), including all 19 papers published in 2011 in the Technical Papers Section of Mining Engineering magazine (Vol. 63) and all 32 papers published in 2011 in Minerals & Metallurgical Processing (Vol. 28). Additionally, this volume contains 31 papers that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All 82 technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our publications staff. As the 2011 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2011

By Taehong Kim, Changsoo (Kevin) Moon, Anil Parikh

"This paper presents an overview and performance evaluation for a reconditioned decades aged open type hard rock TBM utilized for the twin running tunnel excavations of the Second Avenue Subway Project in Manhattan, New York. The TBM tunnel lengths are approximately 2,370 m (7,800 ft, east TBM Tunnel) and 2,190 m (7,200 ft, west TBM Tunnel) with a 6.7 m (22 ft) bored diameter. This “senior” TBM mined through metamorphic rocks consisting of schist, granofels, and pegmatite, and encountered various adverse geological structures, including some relatively heavy groundwater inflows. The ground support was generally pattern friction rock bolts, and steel sets were used in poor ground. This paper presents TBM characteristics and the subsequent performance, such as machine utilization, downtime, cutter consumption rate, net penetration rate, and daily advance rate. Machine operating parameters including thrust, torque, gripping force, and cutterhead RPM, are compared with various accompanying ground conditions. The performance changes between the adjacent tunnel sections are also presented. INTRODUCTION Project Overview The Metropolitan Transportation Authority Capital Construction (MTACC)’s Second Avenue Subway (SAS) Program consists of four (4) phases from 125th Street to Manhattan Battery Park along the 2nd Avenue (see Figure 1) in Manhattan New York. As a part of Phase 1, Contract 1 was awarded to S3 JV (Skanska/Schiavone/Shea) to build a TBM launch box and subsequent twin TBM tunnels from 92nd Street to 63rd Street under 2nd Avenue. Contract 1 was one of the key contracts in Phase 1 to pre-excavate through the footprint of the follow-on underground stations (72nd St. Station, 86th St. Station, and 96th St. Station) by hard rock TBM excavation. The project team included Client MTACC, S3 Tunnel Constructors, Designer, Aecom-Arup JV, and Consultant Construction Manager, Parsons Brinckerhoff. The major elements of Contract 1 included construction of TBM Launch Box supported by secant pile and slurry walls and mining of twin TBM tunnels with a combined tunnel length of approximately 4,560 m (15,000 ft). The dimension of the TBM launch box was approximately 247 m (810 ft) long from 92nd Street to 95th Street, 21 m (70 ft) to 24 m (80ft) wide along the 2nd Avenue, and 18 m (60 ft) to 21 m (70 ft) deep from the ground surface. The launch box was later used for the follow-on 96th Street Station."

Jan 1, 2016

By N. D. Jagger, I. M. Arbuthnot

The recovery and destruction of cyanide in gold tailings is currently a topic of great interest for both financial and environmental reasons. The environmental problem is particularly important in the U.S.A. at present with the environmental lobby waging a campaign to eliminate the problem of migratory birds dying after drinking tailings dam wate. Tough legislation with severe fines and jail sentences for company executives have been introduced in several states for exceeding cyanide limits. To reduce cyanide levels in tailings dams chemical treatment, including acidification, alkaline chlorination, the INCO sulphur dioxide oxidation process and the Degussa hydrogen peroxide process amongst others are being. used. In addition several processes are at various stages of development for the recovery of residual cyanide from gold tailings. Among these is the process developed by Cyprus Gold and pilot tested by DSIR Industrial Development. This process uses air to strip cyanide from the acidified barren pulp and will be used at Cyprus Gold Mines Golden Cross Mine on the Coromandel Peninsula in New Zealand (Fricker & OWers 1990).

Jan 1, 1991

By E. Robert Kiehl

In the early days of the United States, gypsum was most commonly used for the manufacture of plasters with energy being used for quarrying, grinding, and calcining of gypsum rock. With the dramatic switch to gypsum-drywall construction after World War II, the energy usage per ton of rock processed increased more than threefold, and with the rapid growth of the construction industry, the total energy consumption in gypsum-board production alone increased eightfold during the period from 1940 to 1973. The gypsum industry was one of the first to recognize the need for energy conservation and has voluntarily reported its progress to the Federal Energy Administration for the past several years. Efficiencies in the use of energy have resulted in decreasing the unit consumption an estimated 10 percent during the past six years. Improved combustion efficiencies, optimum operating conditions, more liberal use of insulation, and heat recovery will all contribute to the gypsum industry's goal of using less energy. Gypsum products today are vital to over 85 percent of new housing construction in the United States.

Jan 1, 1978

By Earl Cook

Introduction Men like physical power because it gives control over nature and over other men. Physical power comes in two common forms: explosive and non-explosive. In both forms, the most powerful devices yet invented make use of nuclear energy: on the one hand, the hydrogen or fusion bomb, and, on the other hand, a nuclear power plant. For some nations, nuclear power offers a measure of independence not otherwise available in a time of diminishing and unevenly allocated fossil fuels. Consequently, it has great attraction. Unfortunately, the application of nuclear energy (especially fission energy) to either explosive or electrical power entails a singular risk, that of injury from ionizing radiation, both natural and induced; this risk is found in all stages of the nuclear-fuel cycle, from mining of fissionable materials to the disposal of wastes produced in the "burning" of nuclear fuels. The health costs of nuclear power were not fully assessed in the early stages of the development of nuclear technology and some of them were not properly guarded against, either in the USA, which led the world into the nuclear age, or in Canada, which followed an independent path. What I shall do in this paper is to sketch the history of nuclear regulation in our two countries, to point out what I consider similarities and differences, and to suggest that regulatory history, as perceived by a concerned public, has a great deal to do with what is possible today and probable tomorrow, in other words, with public acceptance or rejection of the nuclear option. The U.S. situation As we sow, so shall we reap. In the USA, further expansion of the nuclearpower industry has been almost stymied by government actions that reflect mounting public concern. There is no national storage facility for spent reactor fuel and it has been decided not to reprocess it; consequently, existing power plants are about to choke on their own wastes. Since the Three Mile Island accident, no new nuclear plants have received operating licenses, although several are ready to start up. The uncertainty of future government action has caused the abandonment of plans for a number of new nuclear plants. In addition, many research projects related to medicine and agriculture, which produce low-level radioactive wastes, are about to be shut down for lack of licensed disposal facilities. Some would maintain that this situation has come about because of the low benefit-to-cost

Jan 1, 1980

By Jörg Weidemann, Peter W. Kuchar, Paul Burgwinkel

The West German Ruhrkohle AG and the engineering company BEDIA have developed an emission control system for diesel engines that is suitable for use in underground coal mining, consisting of a granular catalytic converter and a dry cooling system. Its first ever application was to a diesel mining locomotive. In the catalytic converter the exhaust gases pass over porous, platinum-covered ceramic balls in a double tube, oxidizing CO to CO2. Simultaneously, soot particles in the gases are subjected to afterburning. Laboratory tests carried out by BEDIA and at Aachen University of Technology showed that there was a reduction of over 80% in the CO content of the exhaust gases and over 30% in soot emission. The dry cooling system fulfills all the requirements demanded of exhaust cooling underground and does not have the disadvantages of conventional systems. It needs little maintenance, and it is light and compact. The most important components are a waterjacketed exhaust manifold, a tube and shell heat exchanger, a new type of flame arrestor in a stacked crimped ribbon design and a Venturi diluter. The system has its own thermostatically-controlled cooling circuit to keep the exhaust temperature between 120° C and 150° C, thus effectively preventing the tubes becoming blocked up.

Jan 1, 1989

By N. S. Dalal, Xianglin Shi

Metal ions, such as chromium (Cr) and vanadium (V) are found as trace impurities in mineral dust. Since metal ion mediated free radical generation has been implicated in many disease processes, we carried out a detailed investigation of the metabolism of these metal ions by biological redox systems and the possible oxygenated radical generation therefrom. We found that highly reactive Cr(5+) species are generated in the reduction of Cr(6+) by NADPH-dependent glutathione reductase, lipoyl dehydrogenase, and ferredoxin-NADP+ oxidoreductase. The reduced metal ion species react with hydrogen peroxide, to generate hydroxyl (•OH) radicals in a continuous cycle. The enzymatic catalysis processes also involves the reduction of molecular oxygen to the superoxide [(0-1 2)] radical. Thus only a trace amount of metal ions chemisorbed on mineral dusts, such as quartz, can catalyze the generation of the highly toxic oxygenated radical species from cellular hydrogen peroxide, suggesting a new biochemical mechanism for mineral dust induced chronic lung injury.

Jan 1, 1991

By Zhe Liu, Liping Xiao, Jichi Bai, Xuefei Luan

"In order to study the removal efficiency of Cu2+ from acid mine drainage by prepared bentonite-steel slag composite particles, adsorption experiment was carried out. The composite particles were characterized by X-ray Diffraction analysis technique (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared spectrometer (FTIR). The results show that: the composite particles can release alkali to neutralize the acid of acid mine drainage; the adsorption and chemical precipitation of Cu2+ occurred in the whole reaction process; the removal amount of composite particles on Cu2+ was 9.88 mg/g when the reaction reached equilibrium; the FTIR spectra revealed the existence of surface complexation; the SEM micrographs suggested that the composite particles would continue to adsorb and coagulate Cu2+ after the composite particles surface adsorbing Cu2+ and forming precipitate, namely, there was synergistic reaction of adsorption and coagulation; the XRD patterns further showed the existence of cation exchange and revealed that the states of Cu2+ in the surface of the composite particles was Cu-Si-O mineral phase and CuO(Cu(OH)2) polymerization precipitation. The bentonite-steel slag composite particles which can play a role of adsorption-coagulation synergism are excellent multifunctional green environmental mineral materials to treat acid mine drainage containing heavy metal ions.Introduction It is reported (Zuo and He 2013) that with the rapid development of industry, the world demand for mineral resources is increasing, while the problem of mine environmental pollution is becoming more and more serious due to the large amount of mining. The pollution of mine wastewater has become a global problem, in which acid mine drainage (AMD) is one of the most serious waste water. It is also reported (Cong and Zhao 2003) that acid mine drainage containing high concentrations of heavy metals and having low pH value, causing serious negative influence to the mining production and ecological environment. Acid mine drainage is one of the most serious environmental pollution to the mining industry. In recent years, it has been widely concerned by scholars at home and abroad."

Jan 1, 2017

By A. J. Lewis, P. J. Hutcheson, M. E. Robertson, P. A. Moir, K. M. Barfoot

With the content of gold and platinum in the vast majority of ore deposits typically averaging 6 parts per million and less, the accurate and precise measurement of these metals in samples of ore and mining process streams has proven very difficult to achieve by modem spectroscopic analytical techniques. Largely because no other technique has proven suitable, the basic fire assay process has become the accepted international standard for these metals. Fire assay, however, suffers a number of disadvan­tages in the modem, competitive, high technology, and increas­ingly environmentally aware world. It is a labour intensive technique that is difficult to automate, and requires high levels of skill to ensure accuracy and consistency of results. Potentially hazardous chemical reagents are employed, of which, lead, in particular, can be a serious source of contamination to both personnel and the environment if not effectively controlled. Other dangerous elements, such as mercury and arsenic, liberated in high energy furnace operations, are further sources of possible health and pollution hazards. n contrast, the energy dispersive K X-ray fluorescence (K­XRF) technique devised by K X Technology Ltd overcomes many of the technical constraints of conventional low energy X­ray analysis, and has the potential to revolutionise assay opera­tions in precious metal mining. The technology is simply automated, requires basic operator skills, uses no chemicals, consumes less than 20kW, and is capable of detecting gold and platinum to an accuracy of O .1 parts per million by mass. The new third generation design of AZTEC laboratory instrument, released in 1994, is the result of significant technical development. Capable of analysing over 1200 samples per day, and developed primarily for grade control sampling, its applica­tions have spread to gold ore accounting from on-line conveyor belt sampling; screening of exploration samples; measurement of gold in carbon granules for Carbon-in-Pulp process control; and for conducting rapid checks to support key managemen decisions. The economic, rapid, and non destructive analysis ofup to 80g of ore for large numbers of samples, reduces sampling and sub-sampling errors, and provides improved grade estimates for ore bodies. When interfaced to a LIMS, laboratory automation and cost-savings can be further enhanced. The AZTEC design is also being modified for the analysis of platinum. The GOLDSTREAM on-line analysis system is an important new application of K-XRF to the continuous monitoring of process streams in gold ( or platinum) plants and mills. Integrat­ing the technologies of K-XRF to measure total gold, and dissolved gold spectroscopy to measure gold in solution, the insoluble fraction of gold can be deduced, and the effectiveness of the extraction process determined. Slurries are sampled automatically from selected points of the plant and pumped to the system for analysis. The information produced forms the basis for plant control and optimisation.

Jan 1, 1995

By S. D. Bearden

The world's reserve base is adequate for at least 100 years at the current consumption rate. China, India, and the U.S. are expected to remain the leading producing countries. The U.S. will continue to be the largest consumer of the production. None of the known substitutes for barium sulfate are expected to impact existing applications. World production in 1995 was 4,410Mt. This is about 50% of the projected capacity. Consumption is directly proportional to hydro-carbon well installation activity. Imports are expected to continue to supply more than half of the U.S. requirements.

Jan 1, 1997

By Katherine Hynard, Colin Eustace

Suboptimal decisions introduced during the mine planning process are generally a consequence of both a myopic view of planning objectives as well as time and resources available to convert longer-term plans into execution plans. Erosion of strategic mine plan value in conversion to execution plans is likely to amount to billions of dollars each year. When integrated with operations data feeds, simulation and optimization tools can be used to preserve the value in the strategic mine plan. Optimization models are capable of both automating production of execution plans and improving performance. This reduces the manual burden of revising plans while improving alignment with long-term production objectives. Simulation models can also support the process of developing effective execution plans by providing forward visibility of mine operations performance. They can also be used to test the robustness of optimized execution plans and response to operational variability and disturbances.

May 1, 2025

By Fouad Faraj

For every blast pattern, zones of unique material types need to be classified before mining. Most material types can be summarized into different kinds of ore and waste. Blocks generated from blasthole assays are too small to be selectively mined, so areas with a single material classification meeting the mine’s selective mining unit must be defined. Current industry standard practices are to manually draw ore/waste dig limits, but this process is subjective and results in quantities of dilution and ore loss that can be improved upon to enhance the profitability of mining operations. In this study, two weeks of production data from a homogeneous copper (Cu) porphyry and heterogeneous manto-type Cu deposit were used to assess the variability in the hand-drawn dig limits of 20 geologists, mining engineers and ore control specialists, which were compared with the optimal ore/waste delineation. The profit for 20 distinct hand-drawn dig limits for the homogeneous mine varied by 3.7 percent, from $10.5 million to $10.9 million, averaging at $10.8 million. The percentage was nearly double for the more heterogeneous mine at 5.9 percent, from $17.9 million to $19.0 million, averaging at $18.6 million. Using the optimal ore waste delineation, the profit increased to $11.0 million (1.9 percent increase) and $19.3 million (7.0 percent increase) for the homogeneous and heterogeneous deposit, respectively. The natural variability, diggability requirement and selectivity are identified as the main drivers of ore loss and dilution. Recommendations are provided for reducing the subjectivity in manual hand-drawn dig limits by integrating dig limit optimization algorithms as a tool to assist practitioners.

Oct 1, 2024

By K. J. Ma, L. Ma, J. Stankus

The paper’s intent is to evaluate pumpable foamed cementitious mine seal material by determining the shear strength of a generic foamed cement in the laboratory. The tests were conducted on three scales: small-size specimens, consisting of cylinders 4 in. in diameter or 3-in. prisms; double shear medium- size specimens, measuring 13 in. by 10 in.; and large-size specimens, measuring 6 ft by 4 ft by 4 ft. The small-specimen shear tests resulted in average peak and residual shear strengths of 128 psi and 56 psi, respectively. These values are fairly consistent with published shear strengths of foamed cementitious material. However, the other two types of shear tests did not achieve the shear strength of a typical pumpable foamed cementitous mine seal material. Based on the test results, the paper concluded that the structural analysis of cement foam seals should be based on their residual shear strengths, approximately 20 psi, determined from small laboratory-scale tests of the cement foam/concrete or rock interface, and not be based on their peak strengths.

Jan 1, 2015

By J. Kemeny, B. Norton, T. W. BoBo

Digital image analysis systems to quantify particle size of crushed materials have successfully been applied in large-scale mining operations throughout the world. Particle size measurement at various crushing and sieving stages, especially in aggregate production, will facilitate the industry’s desire and need to achieve higher levels of process control and automation. This paper will 1) summarize applications of digital image analysis in the industrial minerals industries and introduce the Split-Online technology; 2) detail an actual recent test application of digital image analysis that ultimately lead to the installation of an automatic, non-invasive particle size distribution monitoring system; 3) document how this information is being applied: and 4) summarize the new Split-Online Aggregates Module now available.

Jan 1, 2004