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By Francis J. Kiessling

Energy and the conversion of potential energy into alternate forms is becoming a topic of household conversation for a larger segment of the world's population as mankind's desire for products derived from the vast array of technological developments continues to expand. The world's use of steel and the high energy consumption related to the production of steel promotes an awareness of the limitations of existing technology and a search for more economical alternates. Terminology such as (BF) Blast Furnace, (BOP) Basic Oxygen Furnace, (EAF) Electric ARC Furnace, (DR) Direct Reduction, (DRI) Direct Reduced Iron and (FC) form coke is becoming commonplace as alternates are being sought to alleviate the energy crunch. Coke production by various methods was developed as early as the seventeenth century in Europe to replace the disappearing hardwood forests that supplied the initial blast furnace fuel in the form of charcoal. In 1880, the Semet Solvay by-product coke oven design was introduced to the United States at Syracuse, New York, to supply coke for use in the production of soda ash, coke oven gas and its by products as the primary source of many organic processes. Although the Semet Solvay coke oven has not been marketed for decades, these coke oven batteries are in use today producing metallurgical coke, coke oven gas, and related by-products.

Jan 1, 1980

By Jens Gutzmer, Helmut Mischo, George Barakos

"It has been nearly eight years since rare-earth elements (REE) became the subject of frontpage headlines. It was when the controversial Chinese export policy for these critical commodities was epitomized in a maritime border dispute with Japan in September 2010 that resulted in the big REE crisis and price spike of 2011 (Barakos et al., 2016c; Mancheri, 2015).The world was dismayed, especially in REE-importing countries such as the United States that was, and still is, totally dependent on Chinese production and exports (Barakos et al, 2016c; Kennedy, 2015). The short-lived alarm initiated a treasure hunt by way of exploration for REE deposits all over the world. The continuously growing demand on the one hand, and the Chinese sovereignty of the REEmarket on the other, led the rest of the world to explore their own REE resources. In just a few years, more than 400 projects were initiated to explore REE deposits outside of China (ERECON, 2015; Goodenough, 2016).The prices of REE, however, dropped rapidly in late 2017 and were in six-year lows, before the 2011 crisis (Barakos, 2017). The viability of even major established producers is being challenged, not to mention the development prospects of potential REEmarket entrants (Barakos et al., 2016b; Rollat et al., 2016). Production cutbacks and industry consolidation in China have impelled REE market experts to forecast that prices have already reached their lowest point and have nowhere to go but up (Adamas, 2015; Roskill 2015). Yet, expectations for increased REE prices are limited and drastic changes are unlikely to happen in the near future, as there is still excess supply in the overall REE market (Barakos, 2017). Nevertheless, the low prices of rare earths are not the only reason that potential producers are struggling to enter the global REE market. Among other parameters, the separation process of the individual elements seems to be the most important factor, as it is technically challenging and expensive to build and to operate."

Jan 8, 2018

By James E. Breland

Society's growing concern over the number of deaths and serious injuries occurring in coal mines, coupled with a growing sentiment to develop and promulgate improved mandatory health or safety standards, was no doubt the basis for passage by Congress of the Federal Coal Mine Health and Safety Act of 1969, being Public Law 91-173 approved December 30, 1969. Even prior to passage of the Act, strong reaction was quick to arise concerning the effect of such legislation upon the coal mining industry. Initial response varied from mild forms of criticism to' the expressed fear of complete suspension of operations and mine closings. Primarily responsible for these early forms of skepticism were speculative or fanciful cost estimates which led operators to contemplate a less than prosperous existence. However, in spite of this unfavorable outlook, the majority of the operators have faced up to the situation and have been striving to comply with the Act and the regulations issued thereunder. While encouraging strides have been made toward implementation of the Act, it must be recognized that noticeable results have been attained only through many months of determined effort and, as anticipated, at quite heavy expense to the operator.

Jan 1, 1973

By Feridon Ghadimi, Saeed Mojeddifar, Massume Khavari

Separation of geochemical anomalies from background is an important and essential issue in the exploration of mineral deposits. Statistical methods are used to separation of anomaly from background. Fractal/multifractal and singularity methods are very suitable for the separation of weak anomalies. For interpolation, various methods could be used such as most distance-weighting methods, kriging, spline interpolation, interpolating polynomials, and finite difference methods. This paper addressed application of multifractal techniques together with finite difference procedure to detect the anomalous regions. Fractal models such as concentration–area, spectrum–area, and singularity index model were selected to identify Pb–Zn anomalies. In this research, 170 samples from 33 boreholes were taken in the Haft-Savaran area and analyzed for determination of Pb–Zn anomaly. Singularity method was a suitable method for separating Pb and Zn anomalies. Also, the results showed that the geochemical anomaly has occurred along NE–SW trend and is consistent with the sulfide mineralization process and the faults of the region.

May 18, 2020

By Xuezhong Wang, Hao Guo, Tao Tu, Qingsheng Liu

The scheelite concentrate was leached with a mixture of sulfuric and oxalic acids. Chemical compositions, mineral phases, and morphology were characterized by XRF, XRD, and SEM–EDS. Based on the results of the single-factor experiments, the response surface methodology (RSM) was chosen to optimize the leaching parameters: temperature, time, and concentrations of sulfuric and oxalic acids. The RSM results indicate that the optimum values for those parameters are as follows: temperature 72 ℃, sulfuric acid concentration 1.48 mol/L, oxalic acid concentration 0.96 mol/L, and reaction time 2 h. Under the optimal leaching conditions, the model predicts a maximum leaching yield of 99.5%, compared to the value of 99.1% obtained experimentally, that is, a discrepancy of only 0.04%. This good correlation shows that the quadratic polynomial equation obtained by the RSM optimization is reliable. The importance on leaching parameters of scheelite is, in decreasing order, temperature, time, sulfuric acid concentration, and oxalic acid concentration.

Oct 11, 2021

By Xiaolong Bi, Shaohua Luo, Longjiao Chang, Shiyuan Cao, Jianan Liu

The abstract discusses the extraction of silica from nickel laterite ore using a hydrothermal process with sodium hydroxide. The effects of reaction temperature, time, and NaOH-to-ore ratio on silica extraction were investigated. The optimal conditions were determined, achieving over 98% silica extraction. The mechanism involves the reaction of Si in lizardite and quartz with sodium hydroxide, forming sodium silicate solution. Other metals like Mg, Fe, and Ni are enriched in the residue.

Apr 21, 2022

By R. Krog, M. Valente, R. Ochsner, W. Marchewka, R. Jensen, R. K. Zipf

A tube bundle system (TBS) is a mechanical system for continuously drawing gas samples through tubes from multiple monitoring points located in an underground coal mine for analysis and display on the surface. The U.S. National Institute for Occupational Safety and Health (NIOSH), in collaboration with Signal Peak Energy (SPE), LLC, Bull Mountains No. 1 Mine, operated a TBS during mining of two bleederless, longwall panels. This paper describes the gas analysis data and its interpretation. As verified by the TBS, coal at the SPE mine tends to oxidize slowly. It was known that a reservoir of low-oxygen concentration atmosphere developed about 610 m (2,000 ft) behind the longwall face. A bleederless ventilation system facilitates formation of an inert atmosphere in this longwall gob and decreases the likelihood of spontaneous combustion. Connections of the mine atmosphere to the surface through subsidence cracks could allow airflow into the longwall gob, revive coal oxidation and increase spontaneous combustion risk. The atmospheric composition of the sealed areas was homogeneous, except in the immediate vicinity of suspected ingassing points. The TBS verified that gases within the partially sealed, bleederless longwall gob expanded into the longwall tailgate area when barometric pressure decreased. The concentration of carbon dioxide in the back return airflow at the longwall tailgate was observed to increase by a factor of three and possibly up to 10 times the typical background concentration of 0.5 to 1.0%, depending on the size of the longwall gob and the magnitude of barometric pressure decrease. TBS have the inherent disadvantage of slow response time due to travel time of the gas samples and sequential gas analyses. A TBS or similar continuous monitoring system could be beneficial in detecting and providing warning of potentially hazardous gas concentrations, if the slow response time of the system is always understood.

Jan 1, 2013

By A. D. Davis

The disposal of spent ore from cyanide heap-leach processing facilities is of concern to the mining industry, regulatory agencies, and the public. Disposal of several hundred million tons of additional spent ore is planned in the western United States during the next decade, with increased amounts likely if gold prices rise. In the past decade, more than fifteen million tons of spent ore have been disposed of in the Black Hills. South Dakota's off-loading criterion for cyanide has been set by the state's Department of Environment and Natural Resources at 0.5 parts per million (ppm) as weak acid dissociable (WAD) cyanide. Nitrate off-loading limits vary for each mine in the state, depending on ore type and other factors. Nitrate concentrations in leachate from spent ore depositories could be caused by conversion from other nitrogen-containing species. One likely source of nitrate is residual explosives from blasting of ore. Previous work on the combustion products of nitrogen explosives has shown incomplete 3xidation (Johansson and Persson, 1970). Another likely nitrate source is degradation of cyanide to ammonia, followed by oxidation to nitrite and nitrate.

Jan 1, 1994

China's coal energy development, characteristics and relationships with atmospheric pollution are reported. Atmospheric pollution sources from coal combustion are analyzed. Some of the projects for clean coal combustion in the Shanghai area include use of industrial briquettes, investigation of coal combustion additives, and blending combustion of coal with industrial wastes. Coal is China's main energy source, and 80 percent of China's annual coal production is used in combustion devices. Coal-flue gases from the domestic stoves and industrial furnaces are the main atmospheric pollution source. China's atmospheric pollution is, in fact, the pollution of coal-flue gases. To 2000, in view of China's energy needs as a developing nation, the atmospheric pollution from coal combustion must receive our utmost attention.

Jan 1, 1994

By E. Maré

Some of the members will probably ask themselves what close relationship exists between hydro-metallurgy and a wet scrubber, but we are sure that as soon as deeper thought is given to the matter it will be realised how vital scrubbing, operations are in metallurgical plants. In ordinary metallurgical installations or pyro-metallurgical processes ore concentrates are first of all shifted from place to place and dust is created. In other cases the ores or concentrates are crushed or dried or roasted, and in each one of these operations dust and fumes, are created. All suspended particles and fumes originating from the abovementioned conditions not only, in many instances, provide health hazards which disrupt production and endanger the personnel in the plant, but also are the source of economic losses through extra maintenance and wear to moving machinery due to abrasion and corrosion. Further losses are incurred by the waste of fine, very often valuable, components. The Party who once said that in several metallurgical plants the bulk of the profits was discharged into the atmosphere by the stack wasn't stretching the truth. There is a place in Africa where a gold producing concern used to lose over 5 oz. of fine gold per day out of a total production of 3000 oz. per month. In another instance, copper concentrate going as high as 80% Cu was discharged into the atmosphere at the rate of 4 tons per day. Realising the value of removing and collecting solids and fumes created in metallurgical plants, a thorough study was made of the available plant and equipment offered on the market. Some units were found very efficient, but very expensive; some others also very efficient but with temperature and maintenance limitations. Some others were also efficient but prohibitive from the point of running costs.

Jan 1, 1963

By Chin Wei Yang

Linear programming (LP) has proven to be a most effective mechanism for modeling a vast array of practical problems, while the development of LP applications in engineering have been extensive enough to show its advantages and limitations. In this paper: we focus on the properties of the widely-wed linear programming transportation (LPT) model formulated and developed by Koopmans (1) . There have been many models of this type applied especially in the field of energy economics (2-7). Since most of these applications can be linked to the seminal work of Henderson (8), we stall present our discussions based on his work.

Jan 1, 1980

By Douglas G. Fox

Outputs from industrial activities planned in the Riley Ridge natural gas project are modeled to determine the potential locations of air pollution impacts on the Bridger and Fitzpatrick Wildernesses in Wyoming. The nature of modeling, especially with regard to its realism, is discussed. Alpine lakes which, along with their watersheds, have minimal buffering capacity are being studied because of their sensitivity to acidic deposition from proposed new air pollution sources. A hypothesis which relates a source's emissions to deposition and lake chemistry in a worst-case sense is presented. Research designed to test the hypothesis and reduce uncertainties is outlined and progress reviewed. Focus is placed on the meteorological transport and atmospheric deposition parameterization contained in the hypothesis.

Jan 1, 1984

By Henry N. McCarl

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Jan 1, 1966

By Pratt Rogers, Aaron Young

This paper considers the mining industry’s need for digital transformation (DT) and presents a three-part review of the foundational components of the DT process: ubiquitous data, connectivity and decision-making. It also provides a discussion on the future of DT in mining as well as a research direction, which identifies the need of academia to provide support for mining companies in the form of both research and the education of digitally literate, dynamically capable mining engineers into the coming decades.

By L. Martin, M. Raffaldi, M. Stepan, D. Benton

The Office of Mine Safety and Health Research, Spokane Mining Research Division, is continuing its high-energy, high-displacement testing of field-scale shotcrete panels. A test program was developed to determine the relationship between applied force, displacement and energy for both unreinforced and reinforced shotcrete panels. Reinforcement options consisted of synthetic macro-fibers, sprayed polyurea liners, chain-link mesh, welded-wire mesh and combinations of them. During testing, photogrammetry was used to measure the geometric changes of the panels, including volume changes and panel cracking. These measurements were correlated with the load and displacement data, allowing visual observation to be related to the applied force and displacement. The test results provide a comparison of the mechanical performance of the various panel types and can assist in interpreting the condition of installed surface support. Visual assessment of the loading cycle and strength capacity of shotcrete in underground excavations will improve mine safety by providing a means to better quantify the stability of installed shotcrete support.

Jan 1, 2016

By Norman R. Paterson

In November 1980 a combined airborne electro-magnetic (INPUT.) and magnetometer survey was conducted by Questor Surveys Limited in the State Line Area, Colorado-Wyoming. The survey was the result of discussions over a prolonged period between the authors and various investigators of the State kimberlite occurrences. As a result of these discussions and literature studies, it was decided that airborne geophysical methods would be potentially useful in the exploration for new kimberlite occurrences. The survey was designed by Paterson, Grant and Watson Limited and conducted by Questor Surveys Limited over an area in which more than 15 kimberlite bodies were known and on some of which ground geophysical surveys had been conducted. The survey was designed primarily to determine the airborne electromagnetic and magnetic responses of the known occurrences and to deter- mine whether these responses would be detectable under similar conditions in other parts of the State Line District and elsewhere.

Jan 1, 1984

By Garry G. Lowder

The regional geologic setting is essentially a volcanic island arc built upon an oceanic basement, consisting of basalt and minor pelagic sediments (the Tinombo Formation of Eocene - lower Miocene age. Trail et. al. 1974). -- An east-west chain of intermediate and acid calc-alkaline volcanoes (the Bilungala Volcanics) was built on the oceanic basement during the Miocene. The Bilungala Volcanics are flanked to the north largely by contemporaneous andesites and volcanoclastic sediments of the Dolokapa Formation. During middle to upper Miocene time the Bilungala Volcanics were invaded by large masses of predominantly dioritic intrusive rock and it is within one of these dioritic intrusive complexes, the Bone Diorite, that the cluster of porphyry copper systems occurs. Renewed volcanic activity in the Plio-Pleistocene produced acid pyroclastic rocks (the Pinogu Volcanicsi whose distribution is controlled by present-day topography. Structural trends, largely interpreted from SLR imagery, are pre- dominantly NW or NIWJ. The right-lateral Gorontalo Fault, which trends hW through the town of Gorontalo (Katili, 19691 is the most prominent structural feature. Many of the major structures in the Tapadaa district have similar orientations and may be sympathetically related to the Gorontalo Fault.

Jan 1, 1976

By Wayne Trudel, Eric Saderhold, Lloyd McEvers, Lori Clarke, Charles Lynn Bolin, Leroy Schutz

Editor’s note: This is the second part of a two-part series on how mine geologists added about 141t (4.53 million oz) at Newmont Mining’s gold operations in Nevada during 2003. Part one (ME, July2004, pp. 19-26) showed how cross-functional teamwork among mine geologists, engineers, metallurgists and operators added $65 million in revenues at Newmont’s Gold Quarry Mine. Part two deals with how this same cross-functional team added about 25.8 t (830,000 oz) of gold reserves and two years of life at the company’s LoneTree Mine. This was done through improved reconciliation methods, pit optimization designs and updated geotechnical parameters. Part two also discusses how Newmont’s Nevada mine personnel added about 62.2 t (2 million oz) of gold reserves at its Twin Creeks Mine, extending the mine’s life by several years. The Lone Tree Mine is a sediment-hosted, micron gold deposit. It is dominantly situated in the Golconda thrust footwall. The north-south trending Wayne Zone fault controls the highest-grade ores and

Jan 1, 2004

By Z. R. Llanos

The petroleum refining industry makes extensive use of catalysts for the conversion of crude oils into more usable products such as gasoline, fuel oil and gas, aromatics, and others. Catalysts used for hydraprocessing contain cobalt-molybdenum or nickel -molybdenum, although there are catalysts that also contain tungsten. During hydroprocessing, nickel and vanadium are deposited on the catalysts, eventually rendering them inactive. The refiners are then confronted with the problem of disposing the spent catalysts. In the past, landfilling was a common method of disposal and it is still practiced in some countries. Other refiners prefer to stockpile the spent catalysts at the refineries until the price of metals warrants their sale to metal reclaimers. This practice, however, poses environmental problems to the refineries for storage and disposal of spent catalysts. Other types of catalysts are amenable to regeneration. The purpose of this paper is to focus attention on the recovery of nickel, cobalt, molybdenum, vanadium, and alumina from spent hydroprocessing catalysts by Gulf Chemical and Metallurgical Corporation and to review the use of sodium hydroxide and sodium carbonate for pressure leaching of spent catalysts.

Jan 1, 1986

By A. S. Henderson

Eastern Mesabi taconite is one of the hardest rocks known, but fortunately it shows little tendency to pack in the crushers, when the minus 5/16 inch material is removed. The crushing circuit is essentially as shown in the Engineering and Mining Journal article, "Reserve's New Taconite Project", dated December, 1956 except that the grizzly screen between the two stages of gyratory crushing has been eliminated. The Reserve operating staffs aim is to utilize the crushing equipment in such a manner that the maximum tonnage of taconite can be crushed to the required size at a minimum cost. As is readily apparent, the primary consideration is to produce a desired size product, with the other operating factors to be balanced, thus achieving the best setting for each crusher. Much effort has been expended toward the development of a satisfactory sized material for feeding the rod mills. The characteristics of this feed must allow the following situations to be handled by the existing equipment: 1. The material being fed to the rod mill must be such that it can be fed into the unit with the proper quantity of water to maintain the correct density within the mill. 2. The rod mill must produce a product from this feed which can be handled without difficulty by the magnetic cobbing and ball mill circuit. 3. The incidental tramp must not exceed that quantity which can be handled easily after the rod mill and after the ball mills.

Jan 1, 1959