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By L. Zhou, D. Bahrami

A reliable and stable ventilation system is essential to the safe operation of underground mines. The stability of a mine ventilation system becomes extremely critical while responding to a fire incident since an unstable ventilation system will pose a risk of airflow reversal. The reversed airflow could bring the fire contaminants such as toxic gases and smoke unexpectedly to working areas. In the past few years, there has been a growing interest in the study of ventilation network stability using the concept of resistance sensitivity, which is described as an indicator of how the airflow in an airway is reacting to a resistance change of other airways. Several methods of calculating the resistance sensitivity in a mine ventilation network have been carried out by researchers and scholars around the world. However, the proposed methods heavily rely on a vast amount of mine ventilation simulations, which are very time and computer-power consuming, especially for a large-scale mine ventilation network. In this paper, a direct derivative method calculating the resistance sensitivities with a single mine ventilation simulation has been developed and implemented into a mine fire simulation software, MFIRE. The results from the direct derivative method were verified against the results from a traditional method. The direct derivative method has been proved to be reliable and accurate.

Mar 2, 2022

By B. Schimm

Mining of material without blasting and / or selectively becomes more and more important for high quality ROM-products. Surface Miners have been developed especially for this purpose. The cutting technology of these machines has been improved, so that harder material as well as wet and sticky materials can be cut with better results now. Especially the cutting drum design and more precise drum manufacturing process now allow production and equal tool wear over a long period. The better knowledge of rock parameters influencing the cuttability and cutting results allow higher production, less cutting tool wear and therefore reduced production costs.

Jan 1, 1999

By J. M. Beck

Mineral property appraisers engaged in eminent domain actions on properties for which mining is the highest and best use must be fully competent in all phases of mineral resource estimation, mine project development, and mine operations (or retain the requisite competent assistance), as well as educated in eminent domain appraisal (USPAP Competency Rule). Failure to ensure such triggers the issue of appraisal competence and demonstrates a flagrant disregard of the myriad code(s) and guidelines to which the appraiser is subject. The cavalier assertion of some vague, undefined “latitude” in the valuation process does not exonerate the appraiser from a disregard of the USPAP Competency Rule. Lack of independence (i.e., “advocacy”) in mineral property appraisal is the usual result of a weak background in mining and/or appraisal theory. While it is readily apparent to those able to recognize it in reports and testimony, judges and juries cannot be expected to detect or recognize purposefully misleading (or even fraudulent) valuation concepts or testimony. Purposeful deception by the appraiser can lead to specious over-compensation of the property owner (thus victimizing the taxpayer); or, a failure to provide appropriate and just compensation to the property owner – yet, the purpose of an eminent domain proceeding is to leave the property owner no richer or poorer as a result of the taking. This paper highlights some of the deceptive practices encountered in litigation settings and raises issues of competency, professional ethics, and the effectiveness of the inherent enforcement capabilities within those institutions awarding professional certifications. INTRODUCTION The practice of eminent domain mineral property appraisal requires (particularly with respect to undeveloped mineral properties) that the appraiser possess the requisite level of competence in all phases of mineral resource estimation, mine project evaluation, mine development, and mine operation (through closure). To the extent the appraiser lacks such competence, it is incumbent on the appraiser not only to divulge this lack of expertise but also to seek competent assistance in the performance of the appraisal. This competence or expertise can only be obtained through a combination of appropriate and relevant technical education and direct mining industry experience. There exist a number of professional certification and/or credentialing authorities that speak to such competency. In a similar manner, eminent domain mineral property appraisal (as the term implies) also requires that the appraiser possess the requisite level of competence in the practice of eminent domain appraisal. This competence or expertise can only be obtained through appropriate and relevant education, direct knowledge of appraisal theory, particularly as it relates to the concept of eminent domain, and licensure.

Jan 1, 2019

By D. A. Norrgran

The term "secondary recovery" has recently brought on a new meaning in view of the depletion of natural resources, energy conservation, plant optimization, and the environmental consciousness that has led to hazardous waste management, recycling, and secondary processing. Many secondary recovery processes are being developed applying mineral processing technology. Gravity separation, magnetic separation, and flotation have all emerged as implicit methods for recovering residual values from various process streams and hazardous constituents from waste streams. Recently, a technique for concentrating metallics has been successfully reintroduced. Although the concept of the eddy-current separator was developed over a century ago, (Patent 400317 issued to Thomas Edison on March 26, 1889) it was not until this last decade that it gained prominent acceptance. The evolution of permanent magnets has provided a cost effective alternative for the generation of high intensity magnetic fields. High energy permanent magnets have substantially reduced the capital and operating costs over the electromagnetic circuits employed in antecedent eddy-current separators. Specifically, in recent years, the strength of permanent magnets has increased several fold with neodymiun-boron-iron rare earth magnets now providing an energy product of 35 million gauss-oersted. Figure 1 shows the evolution in the strength of permanent magnets. The development of these rare earth magnets has led to the design of circuits possessing a magnetic force an order of magnitude greater than that of conventional permanent magnetic circuits.

Jan 1, 1991

On Feb. 16, 2012, the Polish coal mining company Lubelski Wegiel Bogdanka S.A. set the world record for daily production from a plow-equipped longwall, with an output of 24.4 kt (26,900 st) of coal from a single face. The company commissioned the first Cat longwall system at its Bogdanka Mine, near Lublin in eastern Poland, in March 2010 and within six months had raised the bar to nearly 17 kt/d (18,700 stpd) of cut coal. Since then, Bogdanka has continued to increase its daily output with a plow face that began mining in the new 7/VII/385 panel last October, taking the world record to new levels. In addition to the record output achievement, the plow face advanced more than 27 m (89 ft) at a 1.63-m- (5.3-ft-) cutting height. ?We thought this achievement would be impossible for any shearer in seam heights as low as this,? said Zbigniew Stopa, vice president of Bogdanka.

Jan 1, 2012

By Mehdi Noori, Atefeh Azizitorghabeh, Fereshteh Rashchi, Ataollah Babakhani, Sarah Mahmoudi

The focus of this research was to evaluate the synergistic effect of bis(2,4,4-trimethylpentyl) phosphinic acid (CYANEX 272) and di-(2-ethylhexyl) phosphoric acid (D2EHPA), diluted in kerosene, on the extraction and separation of Co(II) and Li(I) from synthetic sulfate solution. The results indicated that using a mixture of CYANEX 272 and D2EHPA was efficient in extracting and separating Co(II) from Li(I). The optimum ratio of CYANEX 272/D2EHPA was found to be 5:1, in which the highest separation factor was obtained (5973.23), and ΔpH0.5 was 4.10. Adding tributyl phosphate (TBP) as a modifier and increasing the temperature improved the metals’ separation rate and extraction efficiency. Thermodynamic studies were also carried out, and ΔH, ΔS, and ΔG values were computed, revealing the endothermic nature of Co(II) and Li(I) extraction by CYANEX 272/D2EHPA mixture. The conducted experiments for the McCabe–Thiele diagram showed the possibility of using two stages to extract over 99% of Co(II) and Li(I). Slope analysis and Fourier transform infrared spectroscopy (FT-IR) were employed to comprehend the Co(II) and Li(I) extraction mechanism using a mixture of CYANEX 272 and D2EHPA.

Jan 17, 2022

By G. S. Austin

New Mexico produced 83% of domestic potash and 27% of domestic consumption in 1992. The potash industry of New Mexico produces sylvite (KCI), langbeinite (K2SO4-2Mg(SO4)2), and artificial K2SO4. Average sylvite grade in New Mexico today is about 14%. The average grade of langbeinite is 8-10% Kp. Commercial potash occurs in the middle or McNutt Member of the Salado Formation (Upper Permian Ochoan Series). The 120-m-thick McNutt Member dips about 1° east and contains 11 of 12 potential ore zones in the Salado. The mineralogy and proportion of clay minerals, up to 7% of the ore, influence optimum milling procedures and ore grade cutoff.

Jan 1, 1994

By J. C. Emerick

Preliminary investigations have shown that wetland-based treatment systems can be an effective and relatively inexpensive control strategy for mine drainage pollution in eastern coal mining regions. This strategy also has potential for western mining regions, although too few systems have been installed in the west to permit general evaluation of the concept for western climates. The construction of prototype systems is encouraged for some situations. Wet-land environments have the capability of removing metals by natural geochemical and biological processes, including precipitation, filtration, ion absorption, and biological uptake and accumulation. Data presented for natural wetlands receiving mine drainage show removal of iron and other metals, and high accumulation of metals in soils and plants.

Jan 1, 1988

By Wang Xuewen, Bao Qingbao, Xie Jiacheng, Yan Zewen

This study puts forward a virtual memory cutting method based on the prediction of AFC shape. The integrated key technologies include the generation of virtual teaching cutting curve, the height adjustment strategy of front and rear drum, cutting height adjustment strategy, the reciprocating cycle of cutting technology and so on. Through the two algorithms, SVM and ELM, the form of the next working cycle can be obtained by rolling prediction using the form information of AFC in the first several circulations. Based on the obtained dynamic fluctuation of the form in the vertical and horizontal working faces, the position and cutting information of the shearer during its operation can be controlled and predicted in advance, the memory cutting template can be adjusted and modified in time. Employing this method, the more stable, accurate and timely memory cutting of the shearer under the uneven coal seam could be realized.

Aug 16, 2021

By J. Kretschmann, O. Drusche, S. Krause

Mining companies are caught between the growing international relevance of ESG (Environmental, Social and Governance) investments and the need to secure their “social license to operate” by considering the needs of their stakeholders. In the search for sustainable business models, the concept of the circular economy (CE) is gaining momentum among practitioners and scholars, as it enables the creation of shared value and thus strengthens the trust of investors and stakeholder relationships. However, there is a lack of a sectorspecific CE framework providing guidance to decision-makers in evaluating promising activities. A gap, which this contribution aims to address.

Mar 2, 2022

By W. H. Renison

This paper will discuss the operation and maintenance of Molycorp's Quests Mine ore conveyor system. The 1.2 m wide, steel cable-reinforced conveyor belts are capable of transporting 1089 kt/h of ore over a belt line distance of 3124 m with a vertical rise of 518 m. A portion of the conveyor runs in a 2057 m long underground decline on a 10° slope. Six 448 kW motors power the main 1.2 m wide belts.

Jan 1, 1984

By Ronald Ludchak

Since coal has been designated as the short-term answer to the threatening world energy crisis, improved surface mining techniques, along with improved extraction and handling equipment, are needed to increase the amounts that can economically be mined by open pit methods. A dwindling supply of low cost oil and gas have dictated a major rethinking of our energy sources and their use. New methods for open pit coal mining have to be found to increase coal production and to meet more stringent reclamation laws. Modern twin-engine elevating scrapers can play a vital role in meeting these needs. They are readily available, with short delivery times, from several experienced manufacturers of earthmoving equipment. Recent developments of the elevator system have extended its working range to include many of the materials commonly encountered in open pit mining. The paper deals with the advantages of using twin-engine elevating scrapers in the performance of various mining tasks. These tasks range from utility work to the major task of using the scrapers as a primary stripping toot and, of even more importance, a stripping- reclamation tool for, with scrapers, the overburden can be moved and redeposited in the same strata sequence or soil horizon as in its natural state. A recap of current applications of the elevating scraper will be presented, along with proposed uses.

Jan 1, 1975

By Justin Reed, Sara Bewley, Dwight M. Kinnes, Maryam Sadeghi, Ed Hart

This study compares wet gravity and dry magnetic separation for preconcentrating an allanite-rich rare earth ore from the Halleck Creek deposit. Material in the –300/+86 μm size range was treated to define a flowsheet that maximizes total rare earth oxide (TREO) recovery. The ore is dominated by feldspar and quartz, with hastingsite, an iron-bearing aluminosilicate. Because hastingsite’s density and magnetic response closely match allanite, it is difficult to reject using conventional methods. Two separation approaches were evaluated: MG12 spirals for gravity concentration and an Induced Roll Magnetic Separator (IRMS) for dry magnetic upgrading. MG12 spirals performed well in the rougher stage but provided limited gains when used as cleaners. When IRMS was applied as the cleaner stage, TREO grade and recovery improved substantially, showing that a dry magnetic cleaner circuit can effectively replace the wet gravity cleaner step. MG12 spirals remain suitable for highcapacity rougher duty, but dry magnetic separation delivers higher selectivity, simpler operation, and eliminates water use—offering a more efficient and sustainable preconcentration route in water-constrained environments.

Feb 22, 2026

By Nick A. Hasenack

A full survey of the laboratory and blast-furnace tests on 2 types of acid pellets is given. From the laboratory tests, carried out in an atmosphere containing hydrogen, it appears that type B, produced out of 100% magnetitic ores, has a far better low temperature disintegration index and a lower reducibility index than type A, produced from a hematite/magnetite mixture. The swelling index, chemical composition and mechanical properties of both types of pellets do not differ significantly. From the blast-furnace test, carried out with a burden consisting of 45% of pellets and 45% of sinter with basicsty ratio about 2.2, and at constant driving rate, it follows that there is no significant relationship between the disintegration value of the pellets and the blast-furnace permeability. If also is concluded that the lower reducibility of the type B pellets leads to a significantly higher coke consumption.

Jan 1, 1975

By David M. Abbott

This paper is a companion to, and amplification of, the ?History? section of the 2014 version of the SME Guide for Reporting Exploration Results, Mineral Resources, and Mineral Reserves (SME Guide). The need for the careful examination and evaluation of mineral deposits has long been recognized. In the book De Re Metallica, Georgius Agricola noted, ?Moreover, a prudent owner, before he buys shares, ought to go to the mine and carefully examine the nature of the vein, for it is very important that he should be on his guard lest fraudulent sellers of shares should deceive him? (1556, p.29). Agricola further stated, ?Now a miner, before he begins to mine the veins, must consider seven things, namely: the situation, the conditions, the water, the roads, the climate, the right of ownership and the neighbors? (1556, p. 30). The elements of Agricola?s seven things, much expanded, are incorporated into the 2014 SME Guide. As reflected in this quotation, veins were the primary concern of mining until 20th century technology permitted bulk mining techniques. The need for standardization of reserve descriptions arose along with the development of western mining in the United States and the concurrent development of mining engineering and mining geology as professions. By the turn of the century, debate about terminology of various classes of reserves was in full swing. Herbert Hoover noted in 1909 (p. 16-17), ?The old terms ?ore in sight? and ?profit in sight? have been of late years subject to much malediction on the part of engineers because these expressions have been so badly abused by the charlatans of mining in attempts to cover the flights of their imaginations. A large part of Volume I of the Institution of Mining and Metallurgy has been devoted to heaping infamy on these terms, yet not only have they preserved their places in professional nomenclature, but nothing has been found to supersede them. ?Some general term is required in daily practice to cover the available field of visible ore, and if the phrase ?ore in sight? be defined, it will be easier to teach the layman its proper use than to abolish it. In fact, substitutes are becoming as badly abused as the originals ever were. All convincing expressions will be misused by somebody.? Hoover (1909) noted that the common terms at the time were: ? Positive ore or ore developed: Ore exposed on four sides in blocks of a prescribed size. ? Ore blocked out: Ore exposed on three sides within a reasonable distance of each other. ? Probable ore or ore developing: Ore exposed on two sides, ? Possible ore or ore expectant: Ore in whole or in part below or beyond the range of vision. Hoover stated that these, and similar terms, overlapped and had the difficulty of failing to account properly for geologic variation in metal distribution beyond the exposed face. Certainly assuming extension of values along a vein is reasonable, but how far? Also, these definitions are for vein deposits, not all types of deposits are in veins. Hoover (1909, p. 19), therefore, defined the following terms. ? Proved ore: Ore where there is practically no risk in failure of continuity. ? Probable ore: Ore where there is some risk, yet warrantable justification for assumption of continuity. ? Prospective ore: Ore that cannot be included in the above classes, nor definitely known or stated in any terms of tonnage.

Feb 1, 2014

By T. P. Weldum, B. J. Mahoski, R. S. Rasmussen

A case study of a systematic approach to grinding circuit steady-state optimization is presented. After an overall review of the flow-sheet, two operating circuits were prepared for detailed testing. Functional performance analysis was chosen as the primary modeling system, and, on this basis, a quality-assurance program for data gathering was implemented. A number of circuit-design and operating variables were investigated. Statistical analysis of plant-test results revealed relationships previously unquantifiable by any other modeling technique. Improvements in the classification system and in mill grinding efficiencies were demonstrated. As a result, there was significant energy cost savings.

Jan 1, 2000

By D. K. DeForest

The olfactory system (sense of smell) is crucial to the ability of fish to avoid predators, recognize kin, and synchronize reproduction (Baldwin et al. 2003). Copper (Cu) has been shown to impair olfaction in juvenile freshwater life stages of salmonids (including Pacific salmon and trout) in some laboratory experiments; and in the United States, public concerns have been expressed that current regulatory criteria for Cu in fresh water are not adequately protective of olfactory function in salmonids (e.g., OSU 2007; Pearson 2007). These concerns have largely been raised because some Cu concentrations that have caused olfactory impairment in salmonids in the laboratory are less than Cu concentrations that have been shown to reduce salmonid survival, growth, or reproduction (the effects endpoints that are typically considered in deriving ambient water quality criteria). However, two important and interrelated points that must be considered: (1) freshwater Cu criteria are "driven" by the sensitivities of several invertebrate species that are more sensitive than the olfactory impairment threshold in salmonids when (2) the influence of water chemistry on Cu bioavailability is properly considered in deriving Cu criteria. Bioavailability refers to the ability of various chemical forms of Cu to interact with receptors on the surface(s) of organisms and thus directly cause toxicity or uptake by the organisms. The toxicity of Cu and other metals to aquatic organisms is a function of water chemistry. For example, acute Cu toxicity in fresh water generally decreases as pH, water hardness (Ca2+ and Mg2+), alkalinity, and dissolved organic carbon (DOC) concentrations increase (Meyer et al. 2007). The U.S. Environmental Protection Agency (USEPA) has recommended hardness-based freshwater aquatic life criteria for Cu and other metals since the 1980s (e.g., USEPA 1985); and hardness-based metals criteria decrease (i.e., become more restrictive) as water hardness decreases. More recently, the USEPA has recommended freshwater aquatic life criteria for Cu based on the biotic ligand model (BLM; USEPA 2007), which accounts for the influence of multiple water chemistry parameters, including DOC, pH, alkalinity, Ca2+, Mg2+, and several other cations and anions. The BLM-based Cu criteria generally decrease as DOC concentration, pH, alkalinity, and water hardness decrease. Because DOC has a stronger influence on Cu bioavailability than water hardness, hardness-based and BLM-based Cu criteria can differ considerably. For example, in water that has low DOC and high hardness, the hardness-based Cu criterion would be relatively high (because it is driven by the high hardness) but the BLM-based Cu criterion would be relatively low (because it is driven by the low DOC). Thus, any evaluation of the protectiveness of Cu criteria against a given effect, such as olfactory impairment, must properly account for the chemistry of the exposure water. Meyer et al. (2013) compiled data on Cu-induced olfactory impairment and olfactory-induced behavioral effects from tests in which BLM parameters were measured. They demonstrated that the USEPA's BLM-based freshwater life criteria for Cu are protective against olfactory impairment, because it adequately accounts for water chemistry (whereas the USEPA's hardness-based Cu criteria are not consistently protective). Olfactory impairment by Cu is now receiving increased attention in Canada and Europe (e.g., Wall 2013; Stang 2013). Accordingly, in this paper we have expanded the analysis of Meyer et al. (2013) to consider copper guidelines from various other countries and whether these guidelines are protective against olfactory impairment.

Feb 23, 2014

By Laszlo Valentyik

Heavy media separation (HMS) is one of the most widely used gravity methods in the mineral industry. The feed is separated, according to the specific gravities, into two products; float (light) and sink (heavy) particles. The universal acceptance of the process is due to simplicity, efficiency and robustness for ease of control. However, if optimum separation is desired during the operation of heavy media plants, a delicate balance of a number of variables is essential. Among the variables, the two which are generally the most frequently checked and controlled are specific gravity and consistency of the medium. The latter is a function of the settling rate of the media. The medium is generally made up of finely ground ferrosilicon, magnetite, galena, shale, quartz sand, clay contaminants and water. The frequently present clay in the medium acts as a stabilizing agent, since the coarse heavy medium solids (called media) would quickly settle if they were mixed only in water. Clay concentration of the medium varies between 3-7% by height (1,2). Although clay is essential for reasonable media stability, clay concentration greater than 7-8% imparts too high a viscosity to the medium, and the feed cannot accurately stratify and therefore separate into the required products. To be on the safe side, plant operators clean the medium from most of the clays, and would rather work at a lower stability than have a very viscous medium on their hands. The most recent advance in the area of consistency control rlas made by the introduction of atomized (spherical) ferrosilicon (3). This extended the upper limit of the use of ground ferrosilicon from 3.3 to approximately 3.6, broadening the range of the optimum operating conditions. A viscosity control method was also worked out by the use of low cost additives which lower viscosity while retaining a favorable low setting rate (4). Recently (5) polymers have been successfully used in oil well drilling muds then the requirements were mainly to suspend and transport cuttings during the periodic shutdowns and dril1ings respectively. The rheological properties of these polymer suspensions are such that they present an infinite viscosity to

Jan 1, 1971

By D. H. Stonehouse

There is no such thing as an industrial minerals industry. There are, however, many industries operating in the general field of industrial minerals. And although we use the phrase "industrial minerals industry" out of sheer convenience, the only common denominator among, say, the potash mining and processing industry, the sulphur-sulphuric acid industry and the granite industry is, in fact, that they each are exploiting an industrial mineral resource. May I quote the person whom I consider to be the reigning Mr. Industrial Minerals, Robert L. Bates, who in the 4th edition, 1975, of Industrial Minerals and Rocks states: "An industry is considered to belong to the industrial minerals field if its operations consist of extraction and processing, but not manufacturing. Thus the mining and beneficiation of feldspar is a mineral industry, but the manufacture of ceramic products is not. In the cement and lime industries, processing merges into manufacture, and the line is less distinct. It disappears altogether in a plant that extracts salt as artificial brines, and makes sodium and chlorine chemicals, all under the same roof."

Jan 1, 1981

By D. Leppert

Mr. Garrett brings up several interesting points with respect to the proposed API specification for "nontreated bentonite." However, although not explicitly stated, these specifications are being written based strictly on bentonites from the Wyoming/South Dakota area. Other sodium bentonites may be suitable for use as drill mud but will be unacceptable since the specifications are designed for Wyoming bentonites. Regardless of the API's intent that its specifications are intended only as guidelines, they are generally adhered to on an international basis and, for practical purposes, might as well be chiseled in stone. Estes (1986) notes that the quality of bentonite available from Wyoming producers has steadily declined since the early 1960's. The plastic viscosity: yield point (PV:YP) ratio was included in the current API 13A specification primarily to prevent excessive polymer treatment of lower quality bentonite to make drill mud. However, with development of polymers designed to control YP, this specification cannot ensure that only high-quality bentonites are used for drill mud. Nor will the new specifications for untreated bentonites. Other sodium bentonites are available. Bentonite produced in southeast Oregon demonstrates superior performance characteristics without addition of polymer or other chemicals. However, the exceptionally high purity of these deposits leads to a relatively high YP:PV ratio since the naturally high YP probably results from the higher purity and smaller particle size of this bentonite (Rath. 1986 and personal communication). These bentonite; typically have a smectite component exceeding 90% (Rath, 1985), compared with 70% to 75% smectite for typical Wyoming bentonites, as determined by X- ray diffraction and tests for colloid content. As evident from the accompanying table, the untreated Oregon bentonite has excellent rheological properties, though different from Wyoming bentonites due to the high purity. Additionally, this bentonite reacts well with polymers typically used in the oil industry, making it eminently suitable for use in a low-solids mud system. The extremely low grit content, less that 0.5% on a 75 mm (200-mesh) wet sieve, greatly exceeds the standards set for Wyoming bentonite. Optimum rheological properties are obtained at a higher moisture content than Wyoming bentonites. At 10% moisture, API 13A maximum, the clay is overdried, again reflecting the high smectite content. In summary, the specifications proposed by the API Task Group will ensure that only Wyoming producers can supply "nontreated bentonite to the oilfield since specifications are

Jan 1, 1990