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By Todd Loudin

A majority of the chemical process industry uses lime in either a powder or liquid form. Engineering and maintenance personnel often face a long and potentially expensive trial-and-error period in order to find the best process equipment to handle lime. Limestone is mined from a quarry in the form of calcium carbonate (CaCO3). Then, it is crushed and fed into a kiln at approximately 1,093° C (2,000° F), where the carbon dioxide is burned off (calcining) to make calcium oxide (CaO).

Jan 1, 2010

By Peter Zhang, Todd Minoski, Gabriel Esterhuizen, Jack Trackemas, Berk Tulu, Morgan Sears

Roof stability in the belt entry is critical for safe and continuous production of coal during longwall mining. Previous studies of roof falls that occurred in belt entries have shown that the roof falls were largely associated with high in situ and longwall-induced horizontal stresses [1,2,3,4]. To properly support the roof in a belt entry, it is important to understand how longwall-induced horizontal stress changes can affect roof stability in the belt entry. Monitoring of horizontal stress changes was conducted in the belt entries of two Pittsburgh seam longwall panels oriented unfavorably to the major horizontal stress. Numerical models were also set up to investigate how horizontal stress concentrates and relieves in the belt-entry roof near the face as panel orientation changes. Both measurements and modeling results show that high horizontal stress concentrates in the belt entry roof within about 15 m outby the face. The study demonstrates that longwall-induced differential horizontal stress can be used to evaluate the horizontal stress concentration factors. The horizontal stress concentration factors change with panel orientation, resulting in high stress concentrations at orientations between 20 and 110° and low stress concentrations between 130 and 180°. Roof support strategies are given for the belt entries under the influence of high horizontal stress. For unfavorably oriented panels in weak roof conditions, supplementary support should be installed during development, and cable bolts should be anchored into a stable roof horizon. The bolting pattern should be designed to cover both entry corners and the entry center to prevent potential roof cutters and sagging.

Jan 1, 2023

By William Gleason

The world has seen unprecedented economic changes in recent years, starting with the stock market collapse of 2008 and the great recession that followed. With these changes, the mining industry, like others, has been forced to find ways to adapt to the shifting and sometimes volatile conditions. It has been a bumpy ride that has not been easy. Prices for most commodities have been in a decline in the past several quarters ? albeit still well above the average prices of 10 years ago ? as the costs of production have been on a steady incline for the past 10 years. Adding to the concern was the report in April that China, which had grown at an average pace of 10 percent/year, for the past decade, slowed to less than 8 percent gross domestic product (GDP) growth this year, catching many off guard. Even gold, once the safe haven for investors during rocky times, stumbled in April of this year, losing 7 percent of its value in two days. So what?s an investor to do ? and how can companies still attract financing? For the first time in 10 years, SME, in conjunction with the New York Local Section of SME, attempted to clear the waters of the mining finance sector with a conference focused on ?Current Trends in Mining Finance.? Held at City University of New York, Graduate Center, April 29-30, the two-day conference attracted 148 attendees and was intended for senior executives and mining industry specialists, covering a range of important topics and trends through 17 panels with about 50 speakers. The presentations came from representatives from some of the most influential companies in the mining and financial sectors, including Citi, Nomura, Societe Generale, Caterpillar, Newmont Mining Corp., Ernst & Young, Export Development Canada (EDC), KPMG, HSBC, Tocqueville Asset Management, BNP Paribas, Revett Minerals, Royal Gold, Environ and ERM.

Jul 1, 2013

Choosing the right valve for corrosive, abrasive slurry applications requires exacting analysis and a comprehensive understanding of the complete slurry process. Within the realm of flow control in abrasive and corrosive slurry applications, there is no room for a one-size-fits-all approach. To ensure minimal maintenance, maximum uptime and the lowest overall cost of ownership, the slurry processing toolbox must contain countless alloy and elastomeric pairings ? each carefully targeted to the particular process medium and conditions. This materials selection process is best tackled by turning to expert slurry application engineers and valve product managers who work closely with customers to specify the optimal valve for the given parameters. ?When plant operators and design engineers apply conventional valves in abrasive applications or use metal seated valves or simply apply the wrong valve for a particular flow control situation, it typically leads to rapid valve failure, the potential for hazardous leakage, unexpected shutdowns and costly downtime,? said Cal Cobb, valve products manager for Weir Minerals North America, manufacturer of Isogate slurry valves for service in mining, minerals processing and metallurgical environments.

Jan 1, 2011

By CAIJUN CHEN, MING ZHANG, ZHENWEI WU, FENG ZHOU, BOQUAN LI, XILIANG ZHANG, ZHOU PU

Traveling grate is a widely used process for iron ore pellet production, but the thermal state of pellets in the drying section is still unclear. In this study, the temperature distribution of the drying section was investigated using computational fluid dynamics (CFD). The results indicate there is a coupling effect in the drying section of a traveling grate. Gas with higher temperature in down-draught drying (DDD) transfers heat to the up-draught drying (UDD) through the gap of the insulation board, and the temperature gradient of the pellet bed changes before reaching the insulation board. The characteristics of pellet bed expected to appear in DDD are displayed in UDD in advance. To verify the model, a contrast experiment was conducted.

Automated drilling in surface mines is here, it?s successful, and it?s already at work in mines around the globe. Coal, copper, iron and gold mines in large mining countries such as Canada, Australia, South Africa, the United States and Chile are meeting mining objectives previously ruled out as unattainable. Pit Viper automation enables operators to accomplish more objectives safely. Operator assist functions like AutoLevel, AutoDrill, Auto Rod Changer and multi-rig teleremote control are a few of the features mines are using to gain consistent, sustainable productivity.

By William Gleason

"Technology of all forms has experienced exponential growth in recent years, and there is no sign of it slowing down. This growth has presented amazing opportunity and significant challenges in nearly every aspect of daily life. Some of these changes are seen and experienced every day as we turn to our smart phones, tablets and smart watches to help with us with everything from directions to the store to managing our health. And other technological growth takes place far away from the public view but can have as much of an impact on our daily life as does shopping at Amazon or connecting with friends on social media.At the “THRIVE 2018, Innovations Advancing Mining” conference presented by SME on Sept. 27 at the Sheraton Pittsburgh Hotel at Station Square in Pittsburgh, PA, the focus was on innovation and how it affects the global mining industry.More than 100 people were on hand for the inaugural event, and they were treated to a unique program that focused on the cutting-edge innovations that will carry the mining industry into the future while increasing safety and productivity along the way.2018 SME President Barbara Arnold was the driving force behind the conference and put together the technical program with a focus on innovation through the entire mining life cycle and into the future. Talks ranged from more efficient and safer ways to extract minerals to some of the most advanced end uses of minerals and metals, including the use of 3D printing to create precision parts for machines and humans from advanced metal alloys.“We need to adapt new technologies to our industry and develop additional technologies as we provide materials and metals for infrastructure and energy development in the United States, around the globe, and to the Moon and beyond,” Arnold told Mining Engineering. “Our inaugural THRIVE conference sets the stage for these innovations to be applied and to continue to be developed. Our mining industry can only continue to thrive with these advances.”"

Jan 11, 2018

By William Gleason

"With desert temperatures climbing high at Caterpillar’s Tinaja Hills Demonstration and Learning Center near Tucson, AZ in September, a group of editors were given a reprieve from the sun and stepped inside the new Cat Minestar Command Center. The movie theater-like temperatures inside were a welcome relief, and the computer screens stationed around the room were an indication of not just how much things have evolved in the mining equipment sector, but also a peek into the future of where mining is headed.Equipment manufacturers like Caterpillar have always had to deal with peaks and valleys in demand that come with mining, perhaps never more so than in the last five years. Sudhanshu Singh, global product manager for Caterpillar, said that in one month in 2012, at the height of the mining Super Cycle, Caterpillar produced more than 150 large mining trucks (haul trucks that carry 136 t/150 st or more). By contrast, Caterpillar produced about 80 of those trucks in the full year of 2016. Between 2012 and 2016, Caterpillar saw its profits drop by 40 percent.“This shows how cyclical the industry is, and it is a testament to the strength of Caterpillar to be able to tolerate the wide swings,” said Singh. Demand for commodities is once again on the rise as are commodity prices with many signs pointing toward a recovery for the mining sector, and Caterpillar has positioned itself for the recovery. During its 2017 press event in September, company officials emphasized that Caterpillar has added strength in its technology divisions by forming new partnerships and adjusting its operating plan.“At the heart of our enterprise strategy is the operating & execution (O&E) model, a strategic framework to identify areas of the business that either create or consume the most value,” said Caterpillar chief executive officer, Jim Umpleby. “Using the O&E model as a guide, we gain a deeper understanding of where we have a competitive advantage, which is key to generating high returns.”"

Jan 11, 2017

By LUIS ALBERTO TORRES-CRUZ

The Plewes method is relatively well known among geotechnical engineers interested in assessing the liquefaction potential of soil deposits. Furthermore, it was one of the four methods considered in the post-failure investigation report of the Feijao Dam I, also known as the Brumadinho Dam, in Brazil. The inclusion of the method in that report is likely to increase its visibility among geotechnical practitioners tasked with assessing the liquefaction potential of tailings. While the authors of the method duly presented it as a screening method, more recent technical literature contains conflicting views on its reliability. Considering the popularity of the method and that the safety record of tailings dams is a cause of great concern, this study assessed the uncertainty of results from the Plewes method. The study concludes that, even under optimistic assumptions, the results of the method are too uncertain for detailed characterization of tailings deposits.

By James R. Jones

It has been 2-1/2 years since the Congress passed the Surface Mining Control and Reclamation Act of 1977 (PL95-87) the Office of Surface Mining every deadline specified in the Act. Hopefully the Congress will begin to realize that specifying unrealistic deadlines does not accomplish the end desire of legislation any sooner -- it only adds to the confusion, and actually hinders orderly, efficient progress. OSM has been sued by all categories of involved parties -- environmental activitist organizations, the states, and the coal operators. This situation has resulted for two reasons: (1) insufficient time was allotted by the Congress to properly develop the regulations and program, and (2) OSM?s philosophy that it must dictate every detail of reclamation operations from Washington, even though many of its people are inexperienced with coal mining. These law- suits are now demonstrating their value. OSM is showing signs of "pulling-in-its horns" and, hopefully, will approach the revised regulations in a more realistic fasion.

Jan 1, 1980

By Clement K. Chase, J. A. Eisele, Paul D. Chamberlain, Terry Laverty, Lee Rice, Larry Sevenker, Albert G. Law, Daryl Tweeton, John Peters

"Name your poison," wrote Forbes, Jan. 3, 1983, in an article describing the plight of much of the mineral industry as it entered the new year. "To ask which (mining) segment is better these days is almost like asking which of several stones would make a better life preserver." "The scene has seldom seemed darker or apparently less promising," said the Mining Journal in June 1982. And the Northern Miner described the year as the third in a "3-year drought which has completely dried up (company) coffers." Thus, 1982 became the worst year for much of the mining industry since the Great Depression. Low prices, commodity surpluses, output reductions, layoffs, temporary and permanent closures, and financial losses made headlines as the general recession continued to hurl blows at an industry facing strong foreign competition, increased government regulations, and plummeting market demand. At fault were tight US monetary policies and the resulting high interest rates that, while forcing inflation to slow, also threw the economic wheels of the country into reverse gear. Automobile production, housing starts, consumer durable sales, and capital spending all fell dramatically. US industrial production fell about 8.5% in 1982, with the GNP dropping by 1.7%. Production Value Not a single mineral escaped this recession. According to the US Bureau of Mines, US nonfuel production value dropped for all but four out of 21 metals and 14 out of 44 nonmetals. Production quantities increased for only gold, lead, and zirconium among metals and for only six nonmetals. Total nonfuel mineral production value dropped a whopping 21% from 1981 levels, the largest decline since 1938 and the first since 1971. Production value was estimated at $20 billion. Metal commodities showed heavier losses than nonmetals-37% vs. 12%-because of their link to depressed automobile and construction industries. Prices From peaks in early 1980, prices of precious and base metals, ferrous and nonferrous metals, and virtually every mineral dropped to 30-month lows in June 1982. Gold dropped to $9.64/g ($300/oz) compared to a high of $27/g ($850/ oz). Silver was quoted below 164/g ($5/oz) versus a $1.61/g ($50/oz) high. Copper was offered at a five-year low of $1.22/kg (55.5¢/lb) compared with a high of $3.30/kg ($1.50/lb). Lead went for 53¢/kg (24¢/lb) versus $1.21 (554). Nickel begged for buyers at $4.19/kg ($1.90/lb) compared to a high price of $7.72/kg ($3.50/lb). Molybdenum was available at or below $8.82/kg ($4/lb), down from a high of $44/kg ($20/lb). Cobalt went for $11/kg ($5/lb) versus $55/kg ($25/lb). Adjusted for inflation, increased currency costs, and currency devaluation, many of these prices are the lowest reached in decades. Financial Profits & Losses Low prices severely impacted companies' earnings, turning profits into sometimes disastrous or fatal losses. Robert Norton, director of the US Bureau of Mines, noting there has been a recession in the mineral industry for years, said, "Profit rates as related to invested capital have been considerably lower (for mining) than those of other industries. Mineral industry profits have been subject to greater cyclical swings and debt equity ratios have been significantly greater than

Jan 5, 1983

By Christopher D. Henry

Environmental geologic maps of the Wilcox and Jackson-Yegua lignite belts of the Texas Coastal Plain delineate land areas on the basis of their natural characteristics. Criteria used to define map units include substrate, soil, topography, geologic process, vegetation, and land use. The maps are useful in planning and reclamation of lignite mines and in meeting the requirements of State and Federal surface mining laws. Specific applications include identification of land capability, recharge areas and geometry of aquifers, flood-prone areas, areas that may qualify for prime farmland status, and other areas sensitive to lignite mining.

Jan 1, 1982

By S. D. Rosenthal

"This article will share my ‘shift in career direction’ journey from corporate mine engineer, with 31 years of mining various commodities with a wide range of responsibilities in a variety of countries, to the world of academia. There are times in one’s career that a change is required, albeit perhaps not as drastic of a change as moving to teaching. This paper will share how the transition arose, the decision to make the change, the challenges of the first year in academia and the journey within academia going into the second year.As a graduate of the Montana College of Mineral Science and Technology (Montana Tech) with a B.S. mining engineering degree in May of 1982, my first job with Utah International in the Farmington, NM area took me back to my home state of New Mexico. Some of you will remember that the early 1980s was not a period of prolific opportunities for mining engineers, given low commodity prices, especially for copper (for example, Anaconda Co. had been taken over by Arco and was in the midst of closing down its Butte operations). Coal was good and the learning opportunities abounded with Utah (which became BHP and then BHP Billiton).Gold was taking off in the mid to late 1980s thanks to use of cyanide and heap leaching technology improvements, coupled with deregulation of the gold price, so I ventured off to work in the gold industry with a (then) junior Canadian company called Barrick at a new acquisition of theirs known as Goldstrike. That same gold surge was causing a shortage of iron ore mining engineers in Australia. So after a few years in Nevada, I uprooted the family and left for a little town in the Pilbara of West Australia, known as Newman, to work in the iron ore industry with BHP Iron Ore. An initial short overseas posting turned into six plus years before transferring to BHP’s Indonesian steam coal mines in Kalimantan on the island of Borneo. BHP was going through a rough period following some ill-fated projects (Magma Copper purchase, Beanup and HBI) and was reviewing assets and staffing, so internal opportunities became scarce. Employees were encouraged to “leave the company and find work elsewhere.” So, off I went to Argentina to try copper mining in the Andes with Minera Alumbrera. This short stint in South America was followed by a move to another mining town, Morenci, AZ, and a posting with Phelps Dodge (now Freeport- McMoRan). After 12-plus years without living close to snow, we moved to the Denver, CO area in a new position with Newmont Mining Corp. Along the way I became a professional engineer (Nevada) and completed a masters in project engineering and management. After 11 years with Newmont, I moved to Butte, MT where I accepted a position as assistant professor of mining engineering."

Jan 1, 2015

Several major impediments threaten the successful delivery of tunnel and under-ground construction projects. In addition to technical design and construction risks associated with tunnel projects, many of which are well understood, budgetary pressures, funding constraints and the complexity of procuring, administering and executing multiple concur-rent projects in a large program could also have a catastrophic impact on the program?s objectives. Contributing factors often include poorly managed design, procurement, construction, managerial, organizational, market and stake-holder risks, as well as nonconforming inputs or outputs to the costs and schedule, or any other potential inabilities to deliver the required or desired results. A strategy to prevent ?failure? of a project requires a proactive and holistic approach to risk management. Through planning, identification, analysis, management, monitoring and control of the project?s risks (both threats and opportunities), attention to management of risk will in-crease the probability and impact of positive events and decrease the probability and impact of events adverse to a project?s objectives.

By M. T. Ityokumbul

Experiments have been carried out to determine the efficacy of bubble column flocculation. An acid-base neutralization method was used to determine the mixing time in a 0.064 m x l.5 m bubble column equipped with a Mott porous sparger. The mixing times decreased as the tracer injection point approached the gas sparger. Preliminary flocculation experiments on two clay samples were carried out. The effects of frother addition and air flow rate are presented and discussed.

Jan 1, 1998

By A. K. Sinha

Research shows that continuous mining sections can normally produce around 950 tons per shift in a seam 5 or 6 ft. thick. The shuttle cars as well as the continuous haulage systems are able to match with the continuous miners in capacity. However, in practice both of the two systems seem to be averaging at around 450 to 500 tons per shift in production. Continuous haulage systems are preferred in thin seams particularly where the floor is soft.

Jan 1, 1981

By W. W. Vaughn

In the technique described and evaluated, detection of mercury is based on the principle of atomic absorption. An analog signal, produced when mercury vapor absorbs ultraviolet light, is converted to digital form and calibrated to mercury concentration. Interferences are eliminated by selectively trapping the mercury on gold. The lower limit of sensitivity, using a 1-gram sample, is 5 parts per billion. A model of the instrument mounted in a station wagon has been tested successfully in the field.

Jan 1, 1964

By Dean D. Turner

Exploration geochemistry requires computer processing for quick and efficient reduction and interpretation. An easy to use microcomputer based geologic workstation fulfills this need and allows the geologist to independently process geochemical data. Functions necessary for geochemical data processing are: 1)Digitizing; 2)Communications; 3)Data base management; 4)Statistical analysis; 5)Mapping analysis; and 6)General purpose applications (ie: word processing). A geologic workstation that can perform these tasks will yield significant advantages in processing and interpreting geochemical data.

Jan 1, 1987

By J. D. Raulerson, R. P. Farias, G. A. Gruber

A flotation process has been developed to successfully treat ore from the Santo Domingo phosphate deposit in Baja California Sur. The ore contained less than 4% P2O5 with quartz, silicates, and carbonates as gangue minerals. Flotation of the low- grade feed in seawater required that the conventional Crago process, comprising direct anionic flotation, deoiling, and inverse cationic flotation, be augmented by an anionic cleaner flotation step, phosphate depression, and a calcite flotation step.

Jan 1, 1988

By J. M. Gambogi

Demand for titanium minerals and pigments increased during 1994 as the world economy expanded. Global consumption of titanium dioxide (Ti02) pigment grew an estimated 5% during 1994, the highest growth rate since 1989 (Industrial Minerals, April 1995, pp. 47-53). Demand for titanium mineral ores and concentrates (feedstocks) grew at a similar rate. Increased demand for Ti02 pigment was met through higher production levels. Increased demand for mineral feedstocks was met through drawdowns in inventory levels.

Jan 1, 1995