Search Documents

By Ezz El Din Abdel Hakim Khalaf, Khalid S. Essa, Marc Munschy, Mohamed A. S. Youssef

This study focused on joint interpretation of the aeromagnetic and radiometric data to allocate and describe the structural elements and mineralization zones such as uranium, gold, and sulfide in the Gebel Umm Tineidba and its surroundings, Eastern Desert, Egypt. The study region is covered by exposures of Precambrian rocks such as gneisses, migmatites, ophiolitic mélange, metavolcanics, younger granites, and Quaternary sedimentary covers. The application of the total intensity magnetic and reduced-to-pole maps, power spectrum, analytic signal, tilt-angle, and local wavenumber maps helps in recognizing magnetic sources distribution, lineament features, and mineral zones delineation. The obtained results indicate that the depths of the deeper NE–SW, NNE–SSW, and N–S trending structures extend from 400 to 1750 m and shallower ones range from 100 to 400 m. Finally, the main trends of these structures affect the probable mineralization zones.

Sep 22, 2022

By L. F. Ruppert, R. C. Milici

Coalbed methane (CBM) is currently being produced from a relatively small area in the Dunkard and Pocahontas basins, in the northern and central parts of the Appalachian Basin, respectively. In general, much of the production occurs where the coal beds are beneath 500 feet or more of overburden, where the rank of the coal is high-volatile B or greater (%Ro >0.8), and where the natural fracture system is enhanced by structural deformation. It is anticipated that near-term CBM development will continue within these areas and will expand in the Appalachian basin as technology improves and as the price of gas rises.

Jan 1, 2003

By J. C. Watts

Monitoring and control of conventional industrial wet grinding circuits is conceptually straightforward. However, since production objectives and operating constraints can vary widely from plant to plant, there is probably no single overall grinding circuit control strategy which is "best" in all cases; in-variably some compromise is necessary between performance desired under ideal conditions and performance achievable in practice. The recent advent of relatively low cost, reliable, high speed small computer systems is revolutionizing daily operations in increasing numbers of metallurgical processing plants. Of special power and capability is a hierarchical computer network like that currently in use at the Pinto Valley Operations of the Cities Service Company. Several satellite processors for key plant areas communicate with a master computer operating under a powerful multitasking real-time operating system. Hardware and software structure is such that downtime on one of the processors -including the master -does not have a major impact on overall system operation. Admittedly, the powerful, core efficient table driven satellite software, which handles process/computer communication, calculation of nonmeasured process variables, and basic Direct Digital Control functions, is difficult to modify. However, important high level process monitoring, report preparation, graphic display, and supervisory control functions -including economic optimization -can be implemented by project engineers at the plant site. Thus, for example, new control strategies can be quickly examined and rapidly evaluated. Such computer monitoring capability also permits use of short duration process pulse tests for approximate dynamic modeling and rapid calculation of controller tuning constants for single loop dominant systems. Following a brief back-ground discussion of the Pinto Valley Project, we present some of the more interesting results and conclusions of our work over the past year.

Jan 1, 1978

By Bruce R. Lipin

Chromite, the only ore of chromium, occurs almost exclusively in mafic-ultramafic rocks and their weathering products. However, not all kinds of mafic-ultramafic rocks are favorable hosts for possible low-grade chromite deposits. For instance, chromium-bearing basalts are not favorable because they commonly contain < 0.3% Cr2O3, and chromite is almost always less than 50 um in diameter, if it is present at all. Chromite-bearing ultramafic rocks in stratifonn and alpine complexes tend to be either ore grade (> 25% Cr203) or very low grade (< 2% Cr203); intermediate rocks are scarce. In most complexes large tonnages exist only in the < 2% Cr2O3 group and the composition of the chromite is commonly unsuitable for metallurgical use. Some nickel laterite districts contain more than 108 tons of material with 2.0% to 5.5% Cr2O3, and hence, chromium could be a byproduct of nickel in some laterite districts.

Jan 1, 1982

By R. L. Summers

The tremendous engineering advances occurring during this past century are very evident within the boundaries of the Anthracite Section of AIME. The Steelton plant of Bethlehem Steel Corporation, located along the Susquehanna River just east of the Commonwealth&apos;s capital at Harrisburg, for more than 105 years has experienced a most dynamic life which has paralleled America&apos;s industrial growth. (Figure 1) In June 1865, just after the Civil War, a group of men met to organize the Pennsylvania Steel Company. The war had brought into sharp focus the vital importance of the railroads to the country&apos;s expansion. Until that time wrought iron rails were used, and the replacing of track after only several months wear had become an almost unbearable cost. The spirit of free, competitive enterprise and the prospects of a lucrative market compelled these men to form that first Pennsylvania Steel Company and to develop better rail products. They issued the following statement: "...our desire to free ourselves from dependence upon a foreign market (has) led to the organization of the Pennsylvania Steel Company, and the parties who have connected themselves with it are determined to produce upon American soil all the principal manufactures of steel that are now, at such a serious cost for freight, commission, insurance, exchange, duty, etc., and often, with so much delay and uncertainty, imported from abroad. (We) are preparing to establish near the consumer, works at which articles of accustomed pattern will be promptly produced, and from the

Jan 1, 1971

By A. S. Azman

The mining workforce experiences high rates of hazardous noise exposure and hearing loss. However, previous studies have identified specific behavioral and attitudinal barriers that keep miners from effectively acting to prevent their own hearing loss. NIOSH has developed several new hearing loss prevention tools and interventions that specifically target these barriers to prevention. The NIOSH Hearing Loss Simulator addresses motivation to take action and knowledge about the consequences of noise exposure. The QuickFit earplug test device and QuickFitWeb online hearing protection tester address barriers to effective earplug and earmuff use by verifying at least 15 decibels of protection. The NIOSH Roll-Pull-Hold technique helps miners obtain better protection through an easy-to-remember set of steps that improves attenuation by 9 decibels. The ?Inquiring Ears Want to Know? fact sheet helps miners to understand audiograms and to use them to maintain their hearing health. Each of these interventions can be used within the context of a comprehensive hearing loss prevention program.

Jan 1, 2010

By William Gleason

"It is the largest mining exhibition in the world that attracts thousands of attendees from around the world to Las Vegas, NV once every four years. Despite the recent struggles in the mining industry, MINExpo International 2016 promises to be as big as ever. In the following pages, Mining Engineering takes a look what some of the more than 1,800 companies plan to showcase during the three-day exhibition.CaterpillarCaterpillar will support MINExpo 2016 with an exhibit showcasing machines, technology, expertise and practical knowledge that miners can apply to help address their cost, productivity and efficiency challenges in today’s mining environment.Caterpillar will once again occupy the largest space at the event and will showcase both surface and underground machines, but the talk at the booth will focus on how Cat technology and know-how combines to help mining operations address and solve the issues that are most important to them. The main stage in the exhibit will feature presentations describing how mining companies, Cat dealers and Caterpillar work together to improve operations.“The challenge for all in the mining industry now is to optimize operations — to drive costs down while creating sustainable businesses that can weather downturns,” said Caterpillar Resource Industries group president Denise Johnson. “We believe that through our expertise and the knowledge of our dealers —combined with innovative technologies and our growing data analysis capabilities — we can help them not only survive, but thrive in these challenging times.” Johnson was selected by the National Mining Association (NMA) to chair MINExpo 2016. “Chairing this show is a great honor, and it’s a testament to Caterpillar’s partnership with this critical industry,” she said. “We’re proud to be a long-time supporter of the NMA, and we are excited to participate in another MINExpo. It’s an opportunity for us all to learn from each other how to increase productivity, control costs and improve overall operations.”Surface mining displays. The surface mining section of the Caterpillar exhibit will showcase the new MD6420C rotary drill. This is autonomy ready and optionally equipped to leverage the safety and productivity benefits of Cat MineStar Terrain. This high-precision drill management system optimizes utilization and improves drilling and blasting operations by accurately guiding the operator and improving precision of hole placement and drilling depth — and the next step is fully autonomous operation, Command for drilling. The third-generation drill incorporates proven Cat components throughout for superior reliability and durability."

Sep 1, 2016

By Jerry C. Tien

Without a doubt, the scope of China?s coal boom has been nonstop. Despite the world economic slowdown, China?s year-on-year gross domestic product (GDP) jumped 10.3 percent year-on-year in 2010, boosted by a faster than expected 9.8 percent expansion in the fourth [ ] quarter. And, the first quarter of 2011 expanded another 9.7 percent. According to a frequently cited statistic, the country is building two mid-sized coal plants each week. This amounts to a yearly increase equivalent to the entire power grid in the United Kingdom. China?s coal production was doubled in the last 10 years, from 1.044 Gt (1.15 billion st) in 1999 to 3.2 Gt (3.52 billion st) in 2010. This is 3.2 times the U.S. production (986 Mt or 1.085 billion st) and nearly half (46.3 percent) of the world?s total coal production (6.91 Gt or 7.6 billion st). This rapid increase of demand for coal has made China the world?s largest coal importer in 2009. With the economic situation improving, this trend is expected to continue.

Jan 1, 2011

By D. Anthony, R. A. Williams, R. Raponi

Barrick Gold Corporation in conjunction with SNC Lavalin Engineers and Constructors have developed basic engineering design for counter current decantation thickener (CCD) plants capable of processing 44 000 t/d. To achieve this throughput in a single train, the largest high-rate thickeners installed to date have been utilized in concert with large process slurry and solution transport systems. Process reliability and plant operability and maintainability have been carefully considered in order to develop a practical, yet cost effective design. The design also incorporates the challenges associated with installation of large equipment and structures in a remote location, with a climatically hostile environment, situated in a high seismic activity zone.

Jan 1, 2002

By John S. Lagarias

While systems to remove sulfur oxides from flue gases have been used at coal fired power plants since 1931, critical need for flue gas desulfurization has only occurred since the late 1960s following the passage of the Clean Air Act Amendments. Commercial and advanced flue gas desulfurization processes (FGD) are reviewed. Advantages and disadvantages of the processes are discussed. Regulatory requirements leading to the development of FGD systems are identified. The location and operation of coal fired plants may be determined more and more by the regulatory requirements for sludge disposal, waste, water discharge and air emissions.

Jan 1, 1978

By J. Paraszczak

Underground metal mining involves many challenges. Economic slowdown, tough international competition and sometimes volatile metal prices put constant pressure on mine operators to increase productivity and to reduce production cost. At the same time, countries such as Canada, the United States and Australia are experiencing skilled labor shortages that might even stall development of certain mine projects. Furthermore, some stages of underground production take place in particularly hazardous environments where the safety and health of miners is at risk. Automation of some processes in underground mining is one of the promising avenues to alleviate some of these problems. Loading and haulage are among the most critical operations and areas where implementation of autonomous vehicles has been targeted. However, although health and safety issues are a primary driver to opt for automation, the latter should ensure an acceptable level of productivity and pro?tability. With this in mind, this article focuses on the factors affecting operational effectiveness of autonomous underground loading and haulage equipment and the means to maximize it.

By Lawrence Pelham

The demand or consumption of fluorspar has been somewhat taken for granted in recent years, except for the specific interest of those that produce, market, and/or consume the commodity. A tradition was established of thinking that as the steel and aluminum industry goes, so goes fluorspar. This is much less true today than in the past. The industry is becoming more dependent on chemical industries that feed primarily off hydrofluoric acid (HF) production. The Bureau of Mines recently published an assessment of world fluorspar reserves and resources that created a foundation of valuable data that can be used to monitor fluorspar availability. Celebrations were held this year commemorating the 100th anniversary of the isolation of fluorine. The United States and other countries continue to struggle with the controversy of ozone depletion and the effect of fluorocarbons on the atmosphere. The goals for the U.S. Government&apos;s strategic stockpile are being reevaluated. The market for fluorine chemicals is changing and diversifying, making it a challenge to assess and forecast fluorspar/fluorine demand. This paper reviews the recent past of fluorspar and helps set the stage for a more detailed assessment of this critical commodity.

Jan 1, 1986

By J. H. Kempton

Refinement of environmental procedures can produce significant cost savings at most mines. Grouting permeable aquifers reduces water pumping and disposal costs. Stable groundwater quality supports reduced groundwater monitoring; and for contaminated groundwater, in-situ or natural restoration should be evaluated. Waste-rock characterization can be minimized using fewer (but more representative) samples, inexpensive surrogate analyses (e.g., NAG instead of humidity cells), and appropriate tests (e.g., avoid meteoric tests on sulfide). Selective waste-rock handling should be compared to random emplacement, which is often cheaper and more stable. Finally, incorporating schedule uncertainty in modeling allows the flexibility to revise mine plans within permits.

Jan 1, 2000

By A. G. Journel

Accurate prediction of recoverable reserves are key to the development and planning of a mining operation. Recovery functions for tonnage, quantity of metal and ore grade are defined and two approaches for their estimation are proposed. The indicator kriging (IK) approach draws on the data rank orders, whereas the multi-gaussian (MG) approach relies on a grade multi-variate distribution hypothesis. Although based on different premises, both approaches yield remarkably similar--and accurate--estimates for recoverable reserves.

Jan 1, 1984

By R. Bryce, T. J. Doughty, K. Stoll

Sulfate-impacted mine waters are under regulatory scrutiny to reduce total dissolved solids (TDS). There are several options to reduce TDS. One option is transforming the soluble sulfate into insoluble ettringite. The Water Company LLC (TWC) patented a process for sulfate removal through ettringite formation by reacting directly with metallic aluminum. Freeport-McMoRan (FMI) and TWC have collaborated to design, build and operate a 10-gallon-per-minute (gpm) ettringite pilot plant to establish reagent consumption, plant availability and full-scale design criteria. Using metallic aluminum as the primary aluminum source for ettringite precipitation eliminates the addition of other ions, resulting in significant demineralization. The pilot plant achieved greater than 98% water recovery, greater than 90% reagent efficiencies and maintained reactor sulfate levels below 250ppm. BACKGROUND Ettringite is a hydrated calcium, aluminum, sulfate mineral with the following formula: Sulfate-impacted mine waters are under regulatory scrutiny to reduce total dissolved solids (TDS). There are several options to reduce TDS. One option is transforming the soluble sulfate into insoluble ettringite. The Water Company LLC (TWC) patented a process for sulfate removal through ettringite formation by reacting directly with metallic aluminum. Freeport-McMoRan (FMI) and TWC have collaborated to design, build and operate a 10-gallon-per-minute (gpm) ettringite pilot plant to establish reagent consumption, plant availability and full-scale design criteria. Using metallic aluminum as the primary aluminum source for ettringite precipitation eliminates the addition of other ions, resulting in significant demineralization. The pilot plant achieved greater than 98% water recovery, greater than 90% reagent efficiencies and maintained reactor sulfate levels below 250ppm. BACKGROUND Ettringite is a hydrated calcium, aluminum, sulfate mineral with the following formula: Ca6Al2(SO4)3(OH)12•26H2O Ettringite readily precipitates in high pH water and by doing so, removes sulfate from impacted waters. The SAVMIN process, piloted in South Africa, is one method to produce ettringite. In this process, aluminum hydroxide is the aluminum source. The Cost Effective Sulfate Removal (CESR) process is similar to SAVMIN, but uses a proprietary aluminum source instead of aluminum hydroxide. Outotec and Veolia also have their own versions of the process using their specialized process equipment. TWC patented a version of ettringite precipitation using metallic aluminum as the aluminum source for ettringite formation. The benefit of using aluminum metal is that no additional ions are added to the process. At high pH, the raw aluminum corrodes in water causing hydrogen gas generation as the water is chemically reduced. This reaction is shown below:

Jan 1, 2019

By J. P. H. Steele, T. Vincent, C. Debrunner, M. Whitehorn

For a variety of reasons, the need for automation of underground mining equipment is growing dramatically, e.g., improved safety and health, availability of labor, deeper mines, and desire for more focused excavation. While there has been tremendous progress made in this direction, much needs to be done to reach the holy grail of an autonomous mining machine. This paper reviews a number of technological developments and presents research and development needs for future development. A report on our current project for the Western Mining Resource Center at CSM is included.

Jan 1, 2000

By D. Potter

Freeport Exploration initiated regional reconnaissance exploration programs in Irian Jaya, the easternmost province of the Republic of Indonesia in 1990 (see figure 1). Irian Jaya occupies the western half of the island of New Guinea. Freeport was awarded an initial contract of work which totaled 2.6 million hectares (6.4 million acres) and was subsequently awarded additional?concessions which added 1 million hectares (2.5 million acres). The concessions require work commitments and periodic relinquishments. Due to these relinquishments Freeport?s current land position totals l. 9 million hectares (4.7 million acres).

Jan 1, 1998

By Jürgen Kretschmann

According to the model of product life cycles, the global coal mining industry is in the stagnation phase. The coal demand of the main consumer, China, has peaked in 2013 and is slowly declining. The Norwegian sovereign wealth fund, the world’s largest, has excluded coal-related companies for ethical reasons. Important players like the UN or the EU have already begun to describe pathways towards decarbonization. Increasing competition between coal mining companies and the mining regions can be expected worldwide if companies want to keep their positions on the global and national coal markets. Companies will focus on the best deposits. European countries like France, Spain, or Germany are only forerunners of this development—their centuries of coal production have been finished. The concept of sustainable development (SD) is fundamentally based on a model of progress where ecological, economic, and social dimensions should be developed equally and positively. But without the idea of competition, the concept of SD is incomplete. Questions arise, such as how can SD be realized on stagnating or declining markets without guarantees for companies “to live forever”? How can SD be a corporate goal in a phase of decline? How can declining mining regions sustainably progress into a better future? The German hard coal mining industry’s lifecycle has ended in 2018 after 60 years of stagnation and decline. As of 2019, all hard coal consumed in Germany will be imported, especially from Colombia, Russia, and South Africa. What has been done in Germany to handle the coal decline in a sustainable way and the lessons learned from this process is described in this paper. It may be useful for mining regions who will face a similar future sooner or later.

By Frederic Chavan, Hans Jakob Windier, Shane Yanagisawa, Willy Ritz

The Zurichberg twin track tunnel is the main segment of the Swiss Federal Railway&apos;s new expressline. A heavy concrete lining with a circular cross-section was chosen to cope with the swelling tendency of the surrounding rock. The 4,356 m (14,300 ft) long, 11.52 m (38 ft) diameter tunnel was driven using a shielded Robbins TBM. A 1.20 m (4 ft) wide, 25 cm (10 in) thick precast lining was placed from within the shield tail as the excavation progressed. Tunnel excavation and initial lining operation were completed in 18 months, averaging 11.86 m/day (40 ft/day) in two nine hour shifts. After breaking through, the final 28 cm (11 in) thick concrete arch lining was cast in place.

Jan 1, 1989

By M. A. Stoakes, H. D. S. Miller

Surface subsidence is becoming an increasingly important factor in the economics of mining Louisiana salt domes due to, amongst others, excessive shaft deformations and land loss to encroaching sea water. The vast majority of subsidence studies have been undertaken on bedded, tabular deposits. It is important to understand the causes of subsidence due to mining domal salt and how it can be minimized. The paper will review the major differences between subsidence caused by domal and tabular evaporite mines, the problems encountered in predicting subsidence, the factors that influence subsidence and, finally, possible alternative mining methods.

Jan 1, 1986