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By A. K. Raina

Blast induced damage to the final wall of rockmass in any civil or engineering application is a major concern to the rock excavation engineers. There are at least four distinct techniques practised by blasting engineers to minimise the damage to the parent rock during blasting that are classified as contour blasting. One of the methods to achieve a smooth wall or rock surface in blasting is pre-splitting, where blastholes in the final row are mildly loaded with explosives and fired first in sequence before the rest of the holes in a round of blast to achieve a split in rockmass. Since blasting is one of the most adopted methods for achieving a final wall in a desired shape, while maintaining the rockmass integrity, the design of pre-split blast assumes importance. There are several variables that determine the final shape of the pre-split face including the rock type, the drill diameter, the explosive characteristics, the orientation of major joints with respect to drill hole, the linear charge density, the spacing of drill holes and inclination of the drill holes. This study attempts to determine the importance and sensitivity of variables in pre-split blasting using historical data from open excavations of a hydroelectric project in India. Keeping in view the multitude of variables, low correlation of independent variables with responses and high level of interactions between the variables that define the blast results, it was found suitable to use ANN to determine the importance and sensitivity of the variables involved. A new method to determine the blast induced damage to rockmass, namely, undamaged area (AUD%), is introduced. Half Cast Factor (HCF%) and AUD%were calculated for a high wall and trenches by digital image analysis technique using the Fragalyst software. Joint spacing and linear charge density emerged as most controlling variables in determining the final result of pre-blast. The relative importance of other variables assuming significance in the case of both the designed outputs is also discussed. A comparative analysis of HCF%and AUD%on the basis of results obtained from ANN analysis is also presented. A futuristic approach concept has also been introduced.

May 30, 2021

By E. Siami-Irdemoosa, S. R. Dindarloo

Ease of excavation or rippability, also called diggability or excavatibility, is a critical decision-making parameter in the selection of both the overburden removal method and the required equipment in surface mining and geotechnical engineering projects. The most widely used method of estimating rippability is rock mass classification. Although there are different classification schemes in the literature, all of them have the two major limitations of sharp transitions at class boundaries and subjective uncertainties in decision making. In this study, the decision trees method was employed as a classification tool for estimating ground rippability, using the four rock mass parameters of weathering degree, uniaxial compressive strength, joint spacing and bedding spacing. The results were compared with those of the widely used method of diggability index rating (DIR) and a fuzzy-based DIR. The problem of subjective uncertainty was resolved in the proposed decision trees method, as the tree rules were derived automatically from the training data sets. Compared with fuzzy-DIR, a decision tree classifier is simpler, needs less computational time and is more appreciable by industry practitioners. Nevertheless, the proposed method is not flawless and, similar to both the conventional and fuzzy DIR methods, yielded poor estimations in particular instances. The limitations of the three methods are discussed.

Jan 1, 2015

By Ernest M. Spokes

Maximum fan efficiency can only be obtained when the fan has the correct combination of size, speed, and blade setting to provide the required flow of air against the mine resistance. As the mine grows older, resistance decreases unless old workings flow is restricted, and new combinations of speed and blade setting or different fan sizes may provide greater economy.

Jan 1, 1977

By Franziska Günther, Helmut Mischo

The calculation of costs for an underground mine, as well as the planning of the equipment and materials to be used, is a complex and time-consuming process. The estimation depends on a multitude of parameters, and all mining processes are interconnected. A novel tool has been developed that enables automated calculation of underground mines and allows for the comparison of the effects of changing individual parameters. Previously, changing individual planning parameters often necessitated a complete recalculation of the mine. The newly developed calculation tool provides an innovative planning aid that allows for more efficient and accurate mine planning and cost estimation. The tool enables the user to implement continuously up-to-data costs and prices. This allows for more accurate planning data and results. The underlying concept of the calculation tool, its implementation at a planned quartz porphyry mine in Germany, and the verification of the tool at an existing underground mine will be presented.

Feb 1, 2025

By M. P. Roy, P. K. Singh, A. K. Mishra, Ashish K. Vishwakarma, Vivek K. Himanshu

Ground vibration is one of the major hazards produced by rock-blasting operation. The accurate prediction of vibration is necessary for designing controlled blasting parameters. The existing vibration predictors consider maximum explosive charge weight per delay and distance as the parameters responsible for ground vibration. These predictors are based on the assumption that the geometrical parameters of the blast will be constant for a site. However, the mining sites with bigger production targets have varying geometrical parameters to suit the excavator utility. Accordingly, the other blast design parameters will also have an impact on ground vibration intensity. A principal component analysis is a dimension reduction technique. This technique along with multivariate logarithmic regression has been used in this paper to predict the ground vibration. The technique has classified the blast design parameters into four principal components. The regression with the scores from these principal components has been carried out. The evaluation of the model performance of predictors along with the existing empirical predictors has been carried out using R2 and RMSE values. The evaluation suggests that the predictor with logarithmic regression followed by principal component analysis gives better performance with respect to the existing empirical predictors.

Jul 30, 2022

By R. L. Grayson

Conventional mine safety wisdom states that "the most efficient mines are also the safest." Since the 1980s, small mines (and contractors) have been targeted as the most dangerous ones because of their fatality records. Statistical testing of 1993 West Virginia safety and production data indicated that the most efficient WV mines were not the safest ones, considering correlations between the severity measure and tons per employee-hour, except for very small mines. This paper will present the results of an extended analysis of WV mine safety using 1993 and 1996 data, concluding with the method used to suggest current priorities for focusing interventions.

Jan 1, 1998

By G. B. Amicucci

Golden Sunlight Mines Inc. operates an open-pit gold mine and cyanidation plant about 11km (7 miles) northeast of Whitehall, MT. Golden Sunlight is a subsidiary of Placer Dome US Inc. Mining is accomplished with conventional open pit drilling, blasting and hauling methods. The mining rate is about 102 kt/d (113,000 stpd). Gold occurs as fine-grained disseminations in a pipe-shaped breccia and in immediately adjacent country rock. The ore body is low grade, averaging 2 g/t (0.059 oz per st) of gold. The metallurgical plant uses conventional carbon-in-pulp (CIP) technology. Daily throughput averages 6.5 kt (7000 st). Recoveries are enhanced through a sand tailing retreatment facility while a preaeration process reduces operating costs. The low grade ore dictates that maximum mill throughput at the desired grind size be maintained. Therefore, in October 1988, an Armco Autometrics (now Denver Autometrics) particle size monitor (PSM) 400 was commissioned. The PSM 400 is an on-line instrument. It measures particle size and percent solids in a slurry stream. The PSM pulls its own sample, deareates the sample and passes it through diametrically opposed ultrasonic sensors. The unit uses ultrasonic sound to measure the deareated slurry stream's particle size and percent solids.

Jan 1, 1991

By DEVY DYSON, Brian Hart, JOHN LANGHANS, Stamen Dimov, STEVE YOPPS

A recent Nevada Gold Mines research program focused on pressure oxidation pre-treatment of a Carlin-type double refractory ore from the Turquoise Ridge Mine. The research team found that both arsenian pyrite and carbonaceous matter were highly oxidized within an hour at 300 °C using a bench-top autoclave reactor and that the gold recovery from the residues after cyanide/carbon-in-leach approached the technical limit set by the amount of gold encapsulated by silicate minerals. Although the 60-min pre-treatment at 300 °C yields robust performance when treating a whole ore, copper additives can catalyze the oxidation rate of carbonaceous matter and reduce the residence time needed at elevated temperature. Certain gangue minerals are susceptible to dissolution in acidic solutions at 300 °C, and this may cause poor gold recovery. This recovery challenge is mitigated by keeping free acid in the discharge solution below a key threshold.

Jun 21, 2022

By J. Hart, P. W. Conrad, S. Rosenthal, R. A. Hogan

The Mining Engineering Department at Montana Technological University (Montana Tech) has a new Mine Safety and Health Administration (MSHA) approved program for Part 46 and Part 48 mine health and safety training. The training program will utilize the facilities and faculty from Montana Tech’s Mining Engineering and Safety, Health, and Industrial Hygiene departments to provide superior mine health and safety training to the mining industry. The faculty of each department includes professionals with experience in safety training and the mining industry. The training program incorporates adult learning techniques and extensive hands-on activities in all training modules. The instruction will exceed MSHA requirements. The resources available on Montana Tech’s campus will be utilized to strengthen the training program providing the mining industry with a world class mine health and safety training program.

Feb 1, 2023

By Emily Wortman-Wunder

As the 2013 president of the Society for Mining, Metallurgy and Exploration, Inc., I am pleased to present the 2013 issue of the Transactions of the Society for Mining, Metallurgy and Exploration, Vol. 334. The timely publication of professional papers that promote the advancement of scientific and technical knowledge is critical for enabling technology transfer. SME plays a key role in this process through its publications. Communication within the mining community is the key to a successful profession and 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 2013 Transactions contains 73 papers covering most every aspect of the mining life cycle and encompassing the diverse sectors of our industry including coal, industrial minerals, metals, health and safety and computational methods. It includes all 18 papers published in 2013 in the Technical Papers Section of Mining Engineering magazine (Vol. 65) and all 33 papers published in 2013 in Minerals & Metallurgical Processing (Vol. 30). Additionally, this volume contains 22 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. Some of the many research highlights from 2013 include discussions of perennial issues, such as how to adequately prepare the next generation of mining engineering students for the workforce (Frimpong et al., pp. 44-52) and how to predict and prevent coal mine bursts and bumps (Pariseau, pp. 60-68), the highly anticipated February Rare Earths issue of Minerals & Metallurgical Processing, and papers analyzing electrical injuries in the U.S. Mining industry (Homce and Cawley, p. 367-375) the latest in assessing the safety and efficiency of operations. All 73 technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our publications staff. As the 2013 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, 2013

By C. Meyer, J. J. Eidel

C. W. Hunt I wish to register strong disagreement with the choices of drilling sites chosen by the Continental Scientific Drilling Committee, while endorsing the stated objectives. Of special significance is the lack of any site involving the metals most needed today in the US, while 9 to 13 km of drilling are allocated to gold and silver districts and 11 to 17 km to base metal (mainly copper) districts. Why is nothing proposed for platinum group or chromite? Is this because the committee did not know of such a site? If so, I offer such a site in California (see Fig. 1). The mineralization shown in Table 1 occurs in a large peridotite body in western Tehama County, CA. Petrography has demonstrated unequivocal evidence of migrated PGE deposited in peridotite and chromite of hypabyssal nature. Active diapirism (due probably to serpentine buoyancy) above a reactivated mantle to surface conduit marks the position of the conduit. Young explosion breccia cemented loosely by volcanic glass and tuff demonstrates the significance of the conduit as the prime source of the various emissions. Deep drilling could result in major metals discoveries as well as shedding light on the grand questions of platinum group mineralization. What role water has played in this occurrence is not yet certain; but chlorine and asphaltite have been detected in and adjacent to native PGM, suggesting a major role for water. The explosion breccia suggests that this excellent site could overlie entrapped geothermal steam.

Jan 6, 1987

By James J. Meadows, Jason D. Pampena, Emanuele G. Cauda, Lauren G. Chubb

Exposure to respirable crystalline silica (RCS) can cause serious and irreparable negative health effects, including silicosis and lung cancer. Workers in coal mines have the potential of being exposed to RCS found in dust generated by various mining processes. The silica content of respirable dust in one single mine can vary substantially over both time and location. The current monitoring approach for RCS relies on the use of traditional air sampling followed by laboratory analysis. Results generated using this approach are generally not available for several days to several weeks after sampling, and this delay prevents timely and effective intervention if needed. An alternate analytical method is needed to reduce the time required to quantify the RCS exposure of mine workers. The National Institute for Occupational Safety and Health (NIOSH) has developed a new method using commercially available portable infrared spectrometers for measuring RCS at the end of the sampling shift. This paper will describe the application of the new field-based RCS analytical process for coal mines, including the use of the new method with the existing Coal Mine Dust Personal Sampler Unit. In a case study conducted by NIOSH with a coal mine operator in West Virginia, field-based RCS analysis was completed at a mine site to evaluate the new technique. The RCS analysis results obtained by the field-based method in this case study showed sufficiently strong correlation with results obtained by the MSHA standard laboratory analysis method to allow the mine operator to use the field-based method for evaluating process improvements.

By Fahimeh Dehghani, Louis Ackah, Tathagata Ghosh, Justin Godbold, Jia Liu, Meisam Peiravi, Manoj Mohanty, Azam Baharlouei

Primary economical deposits of rare-earth elements (REEs) are exhausting all over the world, and it has become necessary to find new sources and methods for their extraction. In addition, increasing the application of REEs in modern technological society has increased its demand globally. One of the important movements to compensate for the future shortages of critical metals is the recovery of REEs from recyclable materials. This paper presents a review of the classification and extraction methods, as well as general applications of REEs with emphasis on secondary sources such as coal and coal byproducts, iron ore tailings, apatite, and phosphate byproducts. An overview of the current state of knowledge on the various methods of REE beneficiation and extraction is covered. These methods include physical separation, as well as hydrometallurgical and bio-hydrometallurgical techniques. The application of these REE extraction techniques for enhanced recovery has been driven primarily by the unique industrial application of these important elements. This paper further explores the existing and potential environmental challenges associated with REE extraction. The authors have presented a wide array of literature, in-depth discussion of the subject, and a succinct summary of processes and relevant case studies.

Sep 23, 2020

By S. G. Britton

"Strategies to improve performance in mining production, maintenance and mineral processing operations have evolved over time from straightforward time studies of individual machine performance in the 1960s-1970s to more sophisticated and better focused statistical and financial tools that have emerged in the 1980s-1990s. These newer strategies fall under the broad descriptive category of operational excellence.Operational excellence is the term that embodies a number of performance evaluating strategies, the most popular and relevant to mining include the following:• Six sigma for addressing errors within mining or milling process and work standards.• Lean manufacturing to optimize organizational and operational performance through continuous improvement.There are other strategies that can be applied as well and this paper is not focused on a review of the pros and cons of any one strategy. However, the common threads in these strategies embody the expectation that expected results from these efforts can be quantified and that value will positively benefit the targeted work process, organizational unit, equipment deployment or time schedule when applied to it as part of continuous improvement efforts.The priority for proceeding with any one or more of these efforts is based on the calculated net value of the required resources to make the change versus the estimated value gained. The practice is identified as the value mapping process.This discussion summarizes the value mapping process methodology used at a mature uranium mine and mill in northern Canada to work through the myriad of potential improvement efforts available through the operational excellence process for continuous improvement."

Nov 1, 2016

By H. Sevim

Mining engineering curriculum has been discussed and debated in meetings and conferences, and opinions and recommendations have been published in the literature since the inception of the official degree-granting mining engineering program at the Columbia School of Mines in 1864. The deliberations have usually been heightened during the periods of boom-and-bust cycles experienced by the mining industry since the 1920s. Currently, the global natural resource industry is undergoing another cycle, called ?super cycle,? characterized by elevated prices for metals and other natural resources. The super cycle is occurring as a result of the large deficit between the global supply and demand for natural resources, due, in large part, to economic expansion and development in countries such as China, India and Brazil. Because of this cycle, there is a shortage of mining engineers in the U.S., Canada and Australia.

Jan 1, 2012

By S. A. Sanderson

The last two decades have witnessed the resurgence in popularity of a century old tool for shaping laws and public policy – the ballot initiative. In recent years, anti-mining special interests have used the initiative process to secure voter approval of measures to ban modern surface mining for gold and silver. In November 1998, voters in Montana approved such a measure1 – the effects of which have been devastating to the mining industry in that state. In November 1999, anti-mining groups sought to place a nearly identical provision on the general election ballot in Colorado. They did not succeed, but the battle over mining’s future continues in the most important forum of all – the court of public opinion. The Colorado measure failed, in large part, because its proponents failed to convey a positive environmental theme. The mining industry also exercised early-on the rights available under state law for administrative and judicial review of the initiative, instead of relying upon the limited relief that would have been available had it waited until after the secretary of state approved the measure for the November election ballot. This article will summarize the ballot initiative process in Colorado and the proceedings that took place over Initiative No. 215.

Jan 1, 2001

By P. A. C. De Ruiter

The Lower Cretaceous salt deposits of the Gabon Basin and Congo Basin were said down on ton of an Burly Cretaceous Lato Jurassic, continental graben fill that represent!) the rifting phase of the Afro-American continent. The salt 13 characterized by high percentages of potash and magnesium salts and the scarcity of sulphates and carbonates. The salt probably originated from a brine that was already enriched in high-soluble salts before entering the Gabon Congo basins. Their low-solubility equivalents are found in the Cuanza Basin of Angola. Commercial mining of the potash salt is only possible in those onshore areas where it is essentially undisturbed, shallow and of the right chemical composition. These conditions are net in Congo where the Holle mine produces from rich sylvinite deposits.

Jan 1, 1978

By Fernando Jorge Dick

Artificial sulphides have been produced on the surfaces of heavy metal-oxide, minerals at elevated temperatures (1) and these sulphides gave consistently similar flotation characteristics as the respective natural sulphides. In the case of tin, the only natural tin sulphide known is herzembergite (SnS) which is found only in minor quantities, and its flotation behavior is not known. Balberyszki, Dorenfeld, and Carmi reported (2) tests with artificial tin oxide and pure cassiterite treated with hydrogen sulphide at temperatures above 750oc. They confirmed that the product could be floated in acid pulps. However, iron sulphides derived from pyrite, limonite, and hematite which are generally the major impurities in tin bearing ores could not be separated from tin sulphides under the conditions used by previous investigators. As a practical matter, if complex tin ores or complex low grade tin concentrates are to be treated by this process, it is necessary to be able to separate sulphidized cassiterite from other sulphidized minerals in the feed. The major metallic minerals, by weight, in complex tin ores are the iron minerals--pyrite, hematite, limonite, magnetite and pyrrhotite. These minerals become (or remain) sulphidized during the sulphidization process.

Jan 1, 1978

By Sandeep Kumar Asarapalli, Sunil Kumar Bisoyi, Bhatu Kumar Pal

Spontaneous heating of coal is one of the major concerns in the coal mining industry. Hundreds of millions of tons of coal are lost each year because of spontaneous heating. If necessary arrangements are made, many fires due to spontaneous heating may be avoided. Therefore, protective measures have become essential to prevent coal from spontaneous combustion. A large amount of coal reserve can be saved by the assessment, suppression, and prediction of spontaneous heating of coal, which also helps in betterment and efficient coal production. The use of chemical retardants can act as inhibitors for the liability of coal toward spontaneous heating by increasing its ignition temperature, thereby, increasing its incubation period. The coal-chemical mixture can be used for whitewashing the exposed coal in galleries as it creates a layer between coal and oxygen in the atmosphere, delaying the oxidation process and ultimately inhibiting the spontaneous heating liability of coal. This work examines the effect of chemicals such as sodium chloride, calcium carbonate, potassium iodide, sodium nitrate, and potassium chloride on the spontaneous heating of a coal sample. Thereby, it suggests a better chemical for inhibiting the liability of coal toward spontaneous heating. The experimentation involves flammability temperature (FT), crossing point temperature (CPT), and differential thermal analysis (DTA). The ignition and oxidation temperatures were found from the above experimental methods for Lingaraj open-cast coal mine samples, with and without adding chemicals. The results are cross-checked and verified through DTA. Correlation analysis was carried out among the results obtained from CPT, DTA, and FT, and better chemical retardants that effectively inhibit coal’s tendency toward spontaneous heating were suggested.

Dec 23, 2023

By Ken Goering, Steve Kral, William Gleason

"Once every four years, the global mining industry gathers in Las Vegas, NV for MINExpo International. According to the show’s organizer, The National Mining Association (NMA), about 44,000 people attended the three-day show from Sept. 26-29. It was a show that featured the latest and greatest in equipment and technology. It also served as the backdrop for a snapshot of the state of the industry and while the picture of a global industry is never completely clear at any one time, one thing that is evident is technology has become a major force in the way mining is done.Had it not been for the awe-inspiring “iron” that was on the show floor in the form of haul trucks and shovels weighing hundreds of tons, one could be forgiven for thinking that they were at the Consumer Electronics Show. From training simulators designed to give a realistic experience of operating mining equipment to virtual reality technology that can take the user into the depths of an underground mine or the middle of a mapped ore deposit, an overriding theme of MINExpo 2016 was that the mining industry is connected like never before.In the north hall of the Las Vegas Convention Center was the GE Mining booth that was designed to showcase its efforts to help create a mine that will be connected from the front office to the face of the underground wall or bottom of the openpit. GE Mining called its booth a digital mine, and it included a suite of technologies that can improve performance, reliability, safety and operations. GE Mining said it views each mine as a mini-city, requiring power, water and transportation. Intelligent, real-time monitoring across the mine allows operators to make data-driven decisions that improve equipment reliability and optimize mine operations for substantial savings. And GE Mining was just one of many exhibitors showing off software that allows various types of equipment to communicate. Its booth sat in the shadow of the Komatsu booth with its new 360-t (400-st) 980E-4 haul truck that included GE’s 360-t (400-st) electric wheel motor. This is just one example of how technology is connecting machines, operations and people around the world and how mining is moving forward."

Dec 1, 2016