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An important problem in mine operations is the classification of material as waste, low-grade stockpile, and ore. This classification must often be made with blasthole data that are widely spaced and that have sampling errors. Geo-statistical simulation techniques combined with basic economic principles allows a procedure for classification that maximizes expected profit. Geostatistical simulation methods (Gaussian, indicator, or annealing-based) allow the integration of hard and soft data in the creation of alternative, equally-probable, realizations of the mineral grade(s). At each location, for each realization, we calculate the "profit" if the block were to be classified as ore or waste The optimal classification is the one that maximizes expected profit (a Maximum Profit Se-lection (MPS) procedure). We discuss the theoretical justification of the method and implementation details. The use of blasthole data from different types of mineral deposits, that is, different levels of continuity, is considered. We also show the efficacy of the procedure with different levels of sampling error. The increased revenue due to the MPS procedure and improved sampling is shown. We show the geostatistical simulation procedure and the uncertainty in block grades that result from incomplete and imperfect sampling. The optimal classification is presented. Optimal block classifications are transferred to realizable dig-limits by hand-drawing polygonal boundaries. We compare the results of the proposed method to classification based on kriging. Limitations and areas of future work are identified.

Jan 1, 1999

By YONGQIONG YANG, Ning Wang, CHONGGUANG LUO, LI ZHU, Hanjie Wen, SHENGJIANG DU, Hannian Gu

Niobium in kaolin clay from the Late Permian sequences was reported in the range of several hundreds of micrograms per gram and was considered as a potential resource for its high concentrations and large areal distribution. Ti-bearing minerals associated with kaolin clay were identified as the main host phase for niobium in some case studies. However, the correlation between the concentration of niobium and titanium is poor, and the types of Ti-bearing minerals and modes of occurrence of niobium are not clear. Typical kaolin clay samples from the Late Permian sequences from southwest China were characterized, and the final products derived from kaolin clay sample were investigated using XRF, ICP-MS, XRD, SEM, and TEM (EDS). The results reveal that there were three types of TiO2 mineral phases in the clay samples: (a) massive TiO2 minerals and (b) aggregates of nano TiO2 minerals did not contain niobium while (c) granular TiO2 minerals were the source of niobium from the EDS analysis. The granular TiO2 minerals included anatase and rutile, both of which were the sources of niobium in kaolin clay in the current study. The findings are of great theoretical implication for source and origin study of Ti-bearing minerals and guidance for separation and recovery of niobium from kaolin clay.

Nov 30, 2020

By D. Lauriski, E. D. Thimons, A. C. Smith, D. C. Fredley

The National Institute for Occupational Safety and Health (NIOSH) and Northwest Barricade LLC (NWB) conducted a study to evaluate the effectiveness of a novel fire blocking gel for use in underground coal mines to extinguish or retard the growth of a coal fire. The gel agent was subjected to controlled laboratory testing to assess its ability to delay coal ignition. It was then evaluated to determine if manual fire hose application could be used to apply the agent to mine roofs and ribs to provide a safe egress for mine rescue teams from a fire area. The gel agent was also evaluated in a water sprinkler system to determine its potential for use in conveyor belt fire suppression systems. The agent was then tested in live-fire exercises to examine its effectiveness in retarding and extinguishing a deep-seated coal fire and wood fire. Lastly, the ability of a mine rescue team to quickly and safely apply the gel agent to a mine entry during a simulated mine fire exercise was determined.

Jan 1, 2011

By William H. Lane

After a number of years of engineering and operating assignments and through many types of evaluations, the need for a simple analytical method of evaluating mine haulage alternatives became obvious. Haulage, like 50 many other facets of mining, is generally a sequence of interconnected events that change, often drastically from mine to mine. Often the operator or the mine engineer has neither the time, manpower, facilities, or information needed to prepare a detailed evaluation. For many studies or for routine variance analysis, that detail may not be necessary. The intent of this article is to present an approach for analyzing mobile mine haulage that is simple and straight-forward. These methods are not designed to replace more formal and detailed procedures that have been developed previously and are available in our technical libraries. They are offered as a tool to be applied to preliminary designs, feasibility studies, and variance analyses where more complete detail is not warranted. These methods will eliminate combinations that are not economical or appropriate before more intensive and complete evaluations are undertaken. These methods may also be used to evaluate ongoing operations and to plan changes in those operations. This presentation describes a series of steps that have evolved for the handling of haulage evaluations. It concentrates on the factors having major impact on the results. Because the approach is a sequence of distinct steps, a case study was chosen as the best method of presentation. This case is a composite of several actual situations that have been encountered within the last few years.

Jan 1, 1978

By M. Eyll-Vetter

The operation of large opencast mines in a densely populated area in the centre of Europe involves an inevitable interference in the region. Thus, this is only possible with general acceptance by the regional stakeholders. In order to achieve this general acceptance, it is necessary to develop sound common concepts and to engage in a continuous dialogue with the stakeholders. The aim is to create seminal structures of relevance to the regional economy, taking into account the interests of the various stakeholders like e.g. authorities, local governments, the regional public, and churches. The recultivation of the mined-out areas represents the offset for the mining activities. RWE Power has reached high acceptance of its recultivation. This high acceptance is illustrated by various examples, from biotopes to high-yield agriculture and recreational areas. Thus, recultivation covers all the elements of sustainable development from social compatibility to ecological as well as economic aspects. This is only achievable through an intensive stakeholder dialogue in the region: The communities concerned are intensively involved in the planning and approval process for the new landscape. As far as social compatibility - one of the aspects of sustainable development - is concerned, the necessary resettlement of whole villages is one of the principal challenges. Over the last few decades, RWE Power has developed an approach that is broadly recognised by the stake-holders in the region. The best proof for this is the high proportion of resettlees taking part in the joint resettlement scheme offered. This can only be achieved by constant involvement of the stakeholders in the resettlement process. In conclusion, it can be stated that RWE Power has implemented a well-functioning stakeholder dialogue that guarantees the general acceptance necessary for mining operations.

Jan 1, 2007

By Ahmed Alghamdi, Salem AlGharbi, Aisha AlHarbi, Owain Morton, Norah AlMuhaisen

This paper addresses the challenges in optimizing the phosphate flotation process, specifically focusing on the variability in P2O5 recovery. An artificial intelligence (AI) driven Flotation Prediction Model was developed to accurately forecast P2O5 grades. Leveraging real-time data from various operational sources, the model provides insights into how operators can opstimize key flotation parameters to enhance product quality and recovery rates. The results demonstrate the effectiveness of AI predictive modeling in addressing operational variability, marking a crucial step toward intelligent operations in the phosphate flotation process.

Feb 1, 2025

By Gerhard Lang

"Slurry Microtunneling is a well-established technology building on over 20 years of experience in successful tunnel installations under all kinds of soil conditions across the U.S. and Canada. Recent microtunnel installations prove that initial hesitation, e.g. curved drives, is fading and long-distance pipe jacking projects as well as lake outfalls are being considered. One of the younger technologies is Direct Pipe®, which combines the benefits of HDD and Slurry Microtunneling. It fits exactly into the area where HDD is not feasible or too risky to apply. The paper points out the benefits of the Direct Pipe® technology for owners, engineers and contractors and discusses the latest developments of Slurry Microtunneling for long-distance, curved drives and sea/lake outfalls with wet recovery of the equipment such as on the ‘Keswick Outfall Project’ in Ontario. The first Direct Pipe® installation in the US was executed in August 2010. Since then, another 22 crossings have been carried out amongst a total of more than 60 Direct Pipe® crossings worldwide. INTRODUCTION Pipelines installed underground are indispensable for supplying the growing world population with water, oil, gas and electricity, for removing wastewater and for providing functioning telephone and communications networks. During recent years the limits of trenchless applications have been permanently shifted, leading to higher and more stringent project requirements and consequently new technologies, either as further development of existing methods, or through the development of new methods by incorporating elements of proven technologies. MICROTUNNELING TRENDS IN NORTH AMERICA Slurry Microtunneling has a wider geological application range in comparison to EPB and hard rock Microtunneling. The Slurry MTBM can be equipped with specific cutting wheels to cope with different soil conditions. The most flexible and most often employed type is the mixed soil cutting wheel, which contains a mixture of disc cutters as well as scrapers for varying soil conditions from cohesive soils (clay, silts) to highly permeable soils including sands, gravels and cobbles and even hard ground formations such as rock and boulders. A detailed geotechnical report provides the appropriate data to configure the MTBM and its features to the ground conditions expected. Mixshield or hydroshield (AVN/AVND) MTBMs in particular, can be safely operated with little overburden (~ 3-5 x machine diameter) and minimum risk of frac-out or settlement on the surface. This is especially beneficial in urban areas with sensitive buildings or for river crossings with protected fish habitats."

Jan 1, 2016

By Valeh Aghazadeh, Shima Barakan, Mina Soleymani, Ehsan Bidari, Morovvat Faridazad

Molybdenite is the most important molybdenum concentrate, which is mainly recovered as a by-product from porphyry copper deposits. Due to the low efficiency of purification processes such as flotation in the reduction of copper content of molybdenum concentrate to a standard level (i.e., less than 0.5 wt.%), further purification by a hydrometallurgical method is required. Although different types of chemical reagents were found to be effective in the leaching of copper minerals from molybdenum concentrate, the mechanisms of these processes remain largely unexplored. In this study, optimal conditions for maximum copper leaching (> 99%) were obtained at the concentration of HCl = 1 M, FeCl3 = 0.5 M, CuCl2 = 0.05 M, CaCl2 = 0.5 M at 75 °C, 500 rpm, and S:L = 1:10 during 60 min. CuCl2 was identified as the most effective leaching reagent for copper dissolution in agreement with Visual MINTEQ model results due to the formation of various types of copper chloride complexes. Furthermore, the electrochemical behaviors of FeCl3, CuCl2, and CaCl2 reagents before and after the leaching process were investigated by the cyclic voltammetry technique. The results of cyclic voltammograms at different scan rates verified the presence of copper chloride complexes, and ferric ions as the oxidizing reagents for better dissolution of copper sulfides. Based on kinetic study results of shrinking core models, both chemical and diffusion reactions controlled the copper leaching process with an obtained activation energy of 33.56 kJ/mol. For recovery of the leached copper, the precipitation process was done by the addition of Na2S at 45 °C, S/Cu = 1, and pH = 9.

Dec 26, 2022

By N. M. Levine

This work defines and systematizes the physical factors of the problem of leaching and demonstrates for the first time the utility of macropore volume, micropore volume, specific surface, pore size distribution and permeability as parameters of leaching based on a study of the recovery of uranium from the Top Black member of Chattanooga Shale.

Jan 1, 1962

By F. C. Townsend

Centrifugal modeling was used to evaluate reclamation schemes of; (a) flocculants, (b) sand/clay mixes, (c) flocculants/sand addition and (d) capping with sand or sand/clay mix. Results suggest the hierarchy of effectiveness is: (d) capping, (b) s/c mixes, (c) flocculants/sand addition and (a) flocculants. Comparisions between currently used large strain consolidation computer programs reveal no difference between piecewise linear or finite strain calculations. Correlations between numerical and centrifugal model predictions reveal excellent agreement on magnitudes; however, rate predictions require improvement in laboratory input data and centrifugal scaling relationships.

Jan 1, 1987

By R. J. Morlock

Prior to 1912, coal research for Republic Steel, Corporation was limited to a periodic box test conducted in a commercial coke oven. Then in 1912, a Koppers movable-wall test oven was -built to research wall pressures for selected blends and to conduct other varied research work. In the 1950's economic pressures caused a reassessment of position resulting in the establishment of a Coal and Coal Chemical research group in 1956. In 1958 this group, along with other groups of research endeavor were incorporated into the new Republic Steel Corporation Research Center at Independence¬ Ohio. Currently this section is divided into four groups. 1) Coal Preparation, 2) Coal-Chemicals, 3) Coal Characterization, and 4) Coal Carbonization. The objective of each group is described, and a brief listing of the work done under the first three groups is indicated. A more detailed description of the studies by the Coal Carbonization group of the coking characteristics of Republic Steel Corporation's coals as blended among themselves or in conjunction with selected purchased coals follows. The wall pressure, contraction, and stability index criteria are specified, and the method of assessing these criteria as a function of blend composition is indicated.

Jan 1, 1963

By F. Habashi

Chile is at present the largest copper and rhenium producer and was before World War I the largest nitrate producer. She is also an important producer of lithium carbonate and molybdenum oxide. An important event in the history of the country is the Pacific War of 1879-1883 in which she acquired the northern provinces initially belonged to Bolivia and Peru. In 1888 Chile annexed Easter Island. The Chilean mineral and cultural history is briefly reviewed together with the people who contributed to her development. The present report is the result of a number of academic and industrial visits to Chile during the period 1992 to 2009.

Jan 1, 2011

By C. Hansen, J. Killey

This paper discusses the replacement of AEROFLOAT ® 1 25 promoter by AERO ® 5688 promoter at Sonora Mining Corp.'s California Mother Lode concentrator. Flotation concentrate is trucked 120 miles to a leach plant in Nevada, so the reduced mass resulting from higher gold grades and reduced talceous gangue and barren pyrite resulting from this change in promoters has brought about a major decrease in shipping costs. Preliminary laboratory testing indicated that free milling gold and controlled amounts of pyrite could be floated using Aero 5688 promoter with reduced dosages of Aero 350 xanthate.2 Extensive plant trials confirmed that the new reagent suite could indeed maintain gold recoveries while reducing total mass. Improved froth characteristics also improved operating flexibility in treating various ore types, and overall reagent costs have been reduced.

Jan 1, 1991

By H. R. Manouchehri

In flotation practices, as particles become finer, such as smaller than 20 μm, process efficiency declines markedly. Selective agglomeration of fine particles is a technique to enhance the recovery of fine valuable minerals in flotation circuits. Different agglomerating methods have been introduced and tested. One method that has recently received much attention is to make use of magnetic force to aggregate fine particles. A selective aggregation of fine paramagnetic particles, such as sulfide minerals, can be achieved in the high-intensity magnetic field prior to or during flotation. The method is simple, selective and effective for fine particles and has low operational cost, though a minimum magnetic susceptibility for fine grains is required to promote the process. In this paper, the implementation of the ProFlote magnetic conditioning device in Boliden’s Garpenberg old concentrator in Sweden, where a complex massive sulfide ore is treated, is presented and discussed based on Boliden’s Garpenberg plant. The results showed an increase in the flotation recovery of fine valuable minerals. Zinc (Zn) production was increased by between 1,100 and 1,500 t/a, while salable yearly silver (Ag) production was increased by 1,500 kg. The copper (Cu) grade in the final concentrate was increased by 1 percent, while reductions in its Zn and lead (Pb) grades were obtained. Moreover, considerable reduction in Zn deportment to the final tail was observed

By F. Arslan

Gold extraction from refractory ores is still a problem. Gold losses in the cyanidation process are mainly due to the presence of sulfides and carbonaceous materials. Oxidation of carbon and sulfide minerals by sodium hypochlorite is a possible method to render the ore amenable to cyanidation, and earlier work by the USBM indicates that electrochemical generation of hypochlorite is promising. Laboratory work was carried out on the oxidation of pyrite and carbon in an electrochemical cell with a sodium chloride electrolyte. The results of preliminary tests are discussed in relation to the mechanism of electrooxidation of refractory gold ores and the estimation of current efficiency.

Jan 1, 1991

By N. B. Aughenbaugh

The People's Republic of China has 582 Gt (641 billion tons) of proven coal reserves. At present, 576.5 Mt (635.5 million tons) of coal are mined a year which makes China the third largest producer of coal in the world. Underground mining accounts for 95% of the total production. This paper will discuss the coal districts, coal types, jurisdiction of coal mining, and methods of underground mining. The article also will outline China's objectives in future planning and development of its coal reserves.

Jan 1, 1982

By B. T. Lusk, J. M. Hoffman, J. Silva Castro

Blast vibration induces sounds within neighboring residences. A housewide vibration and sound monitoring system was installed in a West Virginia home subjected to blasts from various distances and directions. Eighty-nine blast events were monitored and analyzed. Fifteen channels of data were collected, including data from three triaxial geophones, one airblast microphone, one uniaxial geophone mounted on the wall of the house (response channel) and four microphones that recorded CD-quality sound waves inside the house. Each of these channels was recorded on the same time scale. The response channel signal was easily separated into ground vibration and airblast-induced movement, due to differences in the time of arrival. This response channel was then compared to the sounds recorded to determine which component of blast vibration induced the maximum sound response. Blasts at distances less than 762 meters (2,500 feet) had maximum sound responses from both ground vibration and airblast, while for blasts beyond 762 meters (2,500 feet), the maximum sound response was caused by ground vibration without exception. When airblast was identified as the dominant sound generator, the peak amplitude of the sound was directly related to the amplitude of airblast. When ground vibration was identified as the dominant sound generator, the peak amplitude of sound was not related to the amplitude of ground vibration. Findings from frequency analysis showed that the frequency content of sounds inside the house was not related to the frequency content of airblast or ground vibration, regardless of source. This finding suggests that residents will have difficulty determining the source of blast-induced noise in their homes. The proposed airblast response factor (ABRF) can aid blasting operations to determine the dominant source of sounds inside a complainant’s house based on the time-of-arrival relationships. With this site-specific information, public relations responses can be developed accordingly.

Jan 1, 2010

By William D. Cassity, Batric Pesic

Introduction Gold mining on an industrial scale is becoming increasingly dependent on low-grade refractory sulfide ores that contain large amounts of pyrite (FeS2) and arsenopyrite (FeAsS). Gold is usually present as sub-microscopic particles dispersed evenly throughout the sulfide matrix. Without some form of preoxidation, efficient recovery of this finely disseminated gold through cyanide leaching is hampered because the surface of the sulfide particle becomes passivated and impervious to penetration of the cyanide. Traditional methods for recovery of refractory gold from arsenopyrite ores include roasting and autoclave leaching. A modem alternative method is to preoxidize the mineral using the bacterium Thiobacillus ferrooxidans prior to attempting to re- cover the gold through cyanidation. The bioleaching of arsenopyrite ores presents a problem in the mobilization of large quantities of arsenic, present both in the +5 and +3 ionic states. Dissolved arsenic species pose a dual problem: they are -1 to the bioleaching process itself through inhibition of bacterial activity, and they also pose an environmental threat. The arsenate anion (AsO2) has been shown to be more toxic to living organisms, including Thiobacillus ferrooxidans, than the arsenate anion (AsO43) (Collinet and Morin, 1989). There is some disagreement as to the fate of arsenite in bioleaching solution. Mandl, Matulova, and Docekalova (1992) reported that dissolved arsenite concentration was constant during a long-term bioleaching study of chalcopyrite using Thiobacillus ferrooxidans. Torma and Oolman (1992) report that Thiobacillus ferrooxidans has been found capable of oxidizing As3+ to As5+. The solid products of arsenopyrite/pyrite bioleaching include jarosite (MFe3(SO4)2(OH)6 where M can be K+, Na+, NH4+ or H3O+), scorodite (FeAsO4.2H2O), ferric hydroxides, and ferric hydroxysufites (Carlson et. al., 1992; Van Breemen, 1982; Lazaroff et. al., 1982). The particular species formed is a function mainly of pH. Little study has been performed on the effect of solid products on bioleaching. Pesic and Kim (1993) showed that Thiobacillus ferrooridans cells served as a nucleation sites for jarosite particles, which grew rapidly and eventually killed the cell. Most bioleaching studies are performed at low pH&apos;s (<2.0) under uncontrolled conditions. By studying bioleaching of arsenopyrite under controlled pH conditions and at higher pH&apos;s (2.0 to 3.0), the distribution of iron and arsenic between the solid and liquid phases can be controlled, and their effects studied. The objective is to develop a bioleaching process that operates at high efficiency while keeping amounts of dissolved heavy metals low. Pesic, Stohok, and Torma (1993) demonstrated the usefulness of this approach in the leaching of cobaltite (CoAsS) concentrates. Materials and Methods The focus of this study was the bioleaching of arsenopyrite ore by Thiobacillus ferrooxidans. The parameters studied included the effects of pH, and the effects of arsenate (AsO43 and arsenite (AsO2). pH studies included pH set initially but not controlled, and pH controlled continuously with NaOH or LiOH. Bioleaching results from two strains of Thiobacillus ferrooxidans with different adaptation histories were compared. Bioleaching experiments were conducted in 150 ml stirred glass reactors using a strain of Thiobacillus ferrooxidans adapted to arsenopyrite ore, supplied by the U.S. Bureau of Mines. These bioreactors were innoculated with stock cells grown on arsenopyrite ore for 14-16 days. Typical elemental breakdown for this ore was: As, 9.90%; Fe, 18.60%, Stot, 9.26%; Suifide, 7.50%; SiO2, 25.90%. Mineralogically, the ore contained both arsenopyrite and pyrite. Bioleaching efficiency was measured by withdrawing bioleach solution samples at selected intervals, filtering, and measuring the amount of dissolved cobalt, iron, and arsenic by atomic absorption spectroscopy. Because the precipitation of iron and arsenic at higher pH&apos;s would lead to unreliable results, a 100 mg tracer of cobaltite concentrate from the Blackbird mine in southern Idaho was added to solution. Dissolution of the cobaltite tracer was used to indicate bioleaching of the bulk arsenopyrite ore. Cobalt has been shown to be stable in solution even when iron and arsenic were precipitated (Pesic, Storhok, and Tonna, 1993). The pa-

Jan 1, 1995

By KOKOWSKI J., RUDZIŃSKI Ł.

The LUMINEOS network was established in 2013 to monitor mining-induced seismicity in Legnica-Głogów Copper District (LGCD), located in south-western Poland. Since the starting time, the network was improved and today consists of 17 seismometers and 10 accelerometers. Up to now, the strongest recorded earthquake in the region had Mw4.0. Both raw seismic data and earthquakes catalog for events recorded by the LUMINEOS network are fully open and available on the EPISODES platform (https://tcs.ah-epos.eu/#episode:LGCD). During the last 7 years, the network improvements gave us a possibility to increase location accuracy for shallow mining events. This accuracy is influenced by factors such as the configuration of seismic stations, noise level at seismic stations, and the influence of the velocity model. Here we encountered two main issues which are worth to discuss. The first one is the low detection threshold of two seismic stations and their significant impact on the location errors. The second one is the large uncertainty in the S-wave picking. Even though S-waves are not so clearly visible on seismograms, they are very helpful in the estimation of source location and strength of seismic events in the region. In our work, we present the history of LUMINEOS network and corresponding improvement on location accuracy as well as the influence of noisy stations on the error distribution and how it is connected with location results. We also investigate the effect of the S-wave phases and how they are related to the accuracy of the earthquakes locations in the network.

Apr 26, 2022

By C. Geier

Previous mine incidents show weaknesses in mine rescue preparedness from poor training in decision making, leadership and incident command center (ICC) protocols. Computer simulations offer a larger range of training opportunities for mine rescue teams focusing on exploration and communications. The mine rescue simulator developed by the Colorado School of Mines and Rite Solutions Inc. utilizes four computers for the instructor and team, with the instructor monitoring the team?s progress. As the team explores, it relays information back to the Fresh Air Base, which then reports to the ICC. This forces a three-step communication procedure, enhancing the team?s overall communication skills and developing ICC protocols. The simulator is decision-based, demanding team decisions be made quickly. Upon completion, teams commented positively. Generally, participants said that the simulator is useful for learning how to communicate and make decisions during mine rescue emergencies. This mine rescue simulator improves team training, providing effective communications practice with an easy setup and no production interruption.

Feb 1, 2014