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By Y. Luo

Surface subsidence process due to underground coal mining often has the potential to cause problems to buried pipelines. In this paper, a technique for assessing the stress level on a subsidence-affected pipeline is introduced. The main contributors for the stresses on the pipelines are identified. Mitigation techniques for reducing the stress on the pipeline have been proposed and successfully tested.

Jan 1, 1997

By Georgene Renner, Chee Theng, William Gleason

"A walk through the exhibit hall or a glance at the technical programing that was offered at the 2019 SME Annual Conference & Expo and CMA 121st National Western Mining Conference in Denver, CO, Feb. 24-27 makes it evident that the mining industry is an innovative one that is on the cutting edge of technology. However, a glance at the nearly 6,700 attendees of the conference and it is also evident that while the industry is moving forward at a rapid pace in some areas, it is lagging behind in terms of diversity, both in gender and ethnicity.At Monday morning’s keynote session, Hannah Ubi, a millennial and a public speaker who joked that she is the proud owner of a sixth-place swimming trophy and a number of participation medals, addressed a full house that consisted of many men with gray hair or balding heads. The issue of an aging workforce that is rapidly being depleted by retirements is not a new one for the mining industry. In fact, it has been a concern for the industry for more than a decade. The central question has long been, “when the current senior-level people begin to retire, how do we replace them, and how do we fill the knowledge gap that is walking off into the sunset?” SME has been on the front lines in searching for solutions to the impending problem and, along with industry partners, has worked hard to develop programs that will address these issues. Among other efforts, the Society has developed a Ph.D. fellowship program to encourage people to remain in academia to teach the next generation and to help train the next generation to take over in the private sector.“The SME Foundation’s Ph.D. and Career Development Grant program is exceeding expectations at this point with two Ph.D. students graduating and taking a position in academia and two professors achieving tenure,” SME Executive Director Dave Kanagy said during the conference.The Society’s Minerals Education Coalition (MEC) has done its part to help educate future generations about the mining industry with initiatives like EngineerGirl, the Boy Scout Merit Badge and Move Mining, the Shark-Tank-style competition that was held on Monday with five finalists competing for the top prize (ME, April 2019, page 53)."

May 1, 2019

By Georges Cote, Ehsan Alavi, Eren Kusdogan

The City of Toronto's Coxwell Bypass Tunnel is currently being constructed by North Tunnel Constructors (NTC) ULC, a joint venture of Jay Dee Canada, C&M McNally Tunnel Constructors and Michels Canada. This project includes construction of approximately 10.5 km of 6.3 meter finished diameter rock tunnel, five 20 meter diameter storage shafts and eleven tunnel connection drop shafts, along with associated deaeration and adit tunnels. 120 m of Starter tunnel and 70 m of Tail tunnel were excavated with roadheaders to help with the launch of the TBM and as part of the contract base scope work. JayDee Canada in Collaboration with Everest Equipment Co. developed an innovative approach to design and build a stand-alone Ring Machine Erector nicknamed Enterprise to erect precast segmental lining in Starter and Tail tunnels in lieu of Cast-In- Place concrete. This paper describes the design and provides feedback on the innovative procedure used to install the rings.

Jun 23, 2024

By James Humphrey

There is a natural resistance to change in any form. When it comes to implementing a game-changing technology like autonomous haulage on an operating mine site, the resistance can at times appear insurmountable. Whether based on real information or misguided preconceptions, it?s essential that we don?t underestimate the effort it will take to overcome this resistance, while clearly recognizing when it?s worth the effort. These realizations did not happen overnight for sites where autonomous haulage has been implemented. Nor did they happen overnight for manufacturers of autonomous mining equipment. Caterpillar, for example, began building toward autonomy more than 30 years ago and had a truck operating in the mid-1990s. Lessons learned during those early years led to the realization that there was much more to be learned ? not just about the machines themselves, but about the systems and knowledge that must be in place for a successful implementation. Working closely with customers, initiating real-life demonstrations on mine sites, having discussions with regulatory agencies and other stakeholders ? these and many other activities were necessary before autonomy could be fully and successfully launched. After decades of effort, Caterpillar?s first official commercial autonomous mine site went to work in 2011 in Farmington, NM.

By Jayson Ripke, Peter Amelunxen, Brandon Akerstrom, Fernanda Solís

It is commonly known in the industry that one of the key challenges for a greenfield project, such as Capstone Copper’s Santo Domingo project, is the obtention of samples for metallurgical testing and subsequent plant design. To face this challenge, the Santo Domingo project completed 169,692 meters of drilling. The material collected has been used for a variety of analysis including the economic recovery of iron, which contributes significant economic value to the Santo Domingo business case. Composite and variability samples, covering the main geological units considered in the life of mine (LOM) plan, were selected for bench and pilot scale testwork. Davis Tube Tests, small scale Low Intensity Magnetic Separation (LIMS) tests and a pilot utilizing a 48 in (1.2 m), diameter magnetic separation drum were completed. The testwork demonstrated that the Santo Domingo ore could achieve iron concentrate grades of 65% Fe - suitable for blast furnace, and 67% Fe - suitable for Direct Reduction, primarily by concentration of magnetite. The outcomes of this work have informed the iron concentrator plant design and scale up.

Feb 1, 2025

By Carlos Tarazaga

Progressive Design-Build (PDB) is an emerging variation of alternative delivery programs in the underground construction industry. PDB refers to the way a construction project design is developed by the Owner and the Design-Builder in a step-by-step process. According to the Design-Build Institute of America (DBIA), Progressive Design-Build allows the design and construction team to collaborate during the earliest stages of project development. This enables engagement between the three key players in a construction contract: the owner, the designer, and the contractor. Is the PDB the best alternative program delivery for large contracts? What is the perspective of the private sector? This paper will provide an overview of the different alternative delivery programs used in the underground industry, pros and cons of each of programs, and the perspective of the designers and contractors. The paper will focus on how the PDB works, reasons why owners should consider PDB for their projects, best collaboration strategies among owners, designers, and contractors to deliver a successful project, and how to manage the project risks using a PDB method.

Jun 13, 2023

By Antonio Tafra, Rene Dominguez, James Spenceley, Brady Hays

"Extracting one of the world’s most valuable natural resources — copper — hinges on the availability of the world’s most essential resource: fresh water. But try sourcing fresh water in one of the driest places on Earth, Chile’s Atacama Desert.BHP, majority owner of the Escondida copper mine in Chile’s Antofagasta region and Minera Escondida Limitada (MEL), operator of the mine, were looking for sustainable solutions to deliver desalinated water to the mine, while protecting the environment and complying with the local water authorityregulations.The mining giant chose Black & Veatch to solve this challenge.Solving a global miningchallengeMines use large quantities of water for mineral processing and metal recovery. Water supply, and not mineral ore, is often the major constraint to mining production and development of projects, especially in Chile. Mining operations must have a reliable water source that complies with local regulations, without adversely impacting the environment or affecting the water supply of nearby communities.Worldwide, mining companies and their owners, shareholders and regulators are placing new levels of focus on minimizing the impact of mines on the surrounding landscape and communities. Balancing the economic benefits and needs of mining operations with the potential freshwater impacts requires mines to pay serious heed to the environmental and social issues related to water. Today, mining companies are being proactive and are taking action to protect precious freshwater resources while seeking opportunities to reduce and mitigate their water impact.Delivering a desalination solutionBHP and MEL needed an efficient, technologically advanced seawater desalination plant, along with a conveyance system and infrastructure that would carry desalinated water more than 180 km (112 miles) from the ocean to the mine. Four pumping stations convey the water to a reservoir at the mine site, which is 3,200 m (10,500 ft) above sea level."

Jan 6, 2018

By George Hufford

An investigation is made into the applicability of queueing theory to simulating the operation of a large open pit copper mine in the southwestern United States. Actual data from a working mine was used to construct curves for truck loading time, haulage and return time, and dumping times. Known results of investigations of queueing models (Koenigsberg - 1958, Gordon and Newell - 1967, Cabera and Maher - 1973) were used to simulate the actual operation. These did not give acceptable results so commonly used probability distributions were fitted to the actual data. A large computer program known as Q-GERT was used with the various parameters obtained from fitting the curves. Kolmogorov- Smirnov tests were run that showed that this was not satisfactory either. Finally, Q-GERT was used with the actual data from the mine. An appropriate correction factor is then found to apply to the exponential probability distributions tested previously and satisfactory results are obtained.

Jan 1, 1981

By FELIPE SÁNCHEZ, PHILIPP HARTLIEB

Innovation plays a critical role in the mining industry not only as a tool to improve the efficiency of its processes and to reduce costs but also to meet the increasing social and environmental concerns among communities and authorities. Technological progress has also been crucial to allow the exploitation of new deposits in more complex scenarios, such as lower ore grades, extreme weather conditions, deeper deposits, harder rock mass and high-stress environments.  

By C. B. Henderson

The development of slurries of coal and water as a boiler fuel replacing No. 6 fuel oil has been actively pursued at the Atlantic Research Corporation since 1976. Funding for this effort has been provided by the U.S. Department of Energy, the Electric Power Research Institute, and by corporate funds. The name ARC-COALTM has been selected for these slurries. Stable coal-water slurries with bone-dry coal loadings between 62% and 77% have been prepared, evaluated rheologically, and successfully burned in an experimental furnace without the assistance of other fuels. The advantages and properties of these slurries, including combustion results, are reviewed. Also discussed is the pilot line used for processing barrel quantities of fuel and a pilot plant capable of processing 600 bbl/day, currently being designed.

Jan 1, 1982

By Hooman Askari-Nasab, AHLAM MAREMI, EUGENE BEN-AWUAH

In oil sands mining, tailings are voluminous unwanted byproducts generated from extracting the desired mineral from the mined ore. Dyke construction and backfilling activities require well-managed techniques to facilitate progressive reclamation at the earliest opportunity. This directly affects the sustainability and profitability of the mining operation. This research introduces a goal programming framework that simultaneously optimizes the (1) production schedule with limited duration stockpiling and directional mining, (2) dyke construction schedule, (3) size, shape and location of tailing cells and (4) mining and processing production targets. The results show that in creating in-pit tailing-cell designs, decreasing the mining-cell volume and increasing the number of mining cells improves the net present value (NPV) of the operation due to increased operational flexibility.

By J. M. Hans, M. F. O’Connell, G. E. Eadie

INTRODUCTION The U.S. Environmental Protection Agency (EPA) was required, under Section 114(c) of Public Law 95-604, to provide a report to Congress identifying the location, and potential health, safety and environmental hazards of uranium mine wastes together with recommendations, if any, for a program to eliminate the hazards. The approach taken to prepare the report was to develop model active and inactive mines and locate them in a typical mining area to estimate their environmental impact. A list of uranium mines was acquired from the U.S. Department of Energy (DOE). The inactive mines were separated from the list and sorted into surface and underground categories. A literature search was conducted to obtain and consolidate available information concerning the environmental aspects of uranium mining and shortterm field surveys and studies were conducted to augment this information base. Radioactivity emission rates were measured or estimated for each mining category and were entered into computor codes to assess population exposures and subsequent health risks. The general environmental condition of inactive uranium mines was determined by walk-through surveys in several mining areas. INACTIVE SURFACE MINES We assumed that a model inactive surface mine contains a single pit with the wastes (overburden and sub-ore) stacked into a pile adjacent to the pit area. No credit for reclamation is given to the model mine. In lieu of the availability of individual mine production statistics, the model surface mine size was established from the total ore and waste production statistics for all surface mines, divided by the number of inactive surface mines. The number of inactive mines, obtained from the DOE mine listing, are summarized by type and location (Table 1). For modeling, we assumed that there are 1,250 inactive surface mines. The total or cumulative waste and ore production for inactive surface mines from 1950 to 1978 is not fully documented. Uranium mine waste and ore production statistics, on an annual basis, were available for both surface and underground producers from 1959 to 1976 (D0159-76). Annual uranium ore production for each uranium mining type are available for 1948 to 1959 (DOE79) and for combined ore production TABLE 1. Consolidated list of inactive uranium producers by State and type of mining [State Surface Underground AL 0 9 AZ 135 189 CA 13 10 CO 263 902 ID 2 4 MT 9 9 NV 9 12 NJ 0 1 NM 34 142 ND 13 0 OK 3 0 OR 2 1 SD 111 30 TX 38 0 UT 378 698 WA 13 0 WY 223 32 Total 1246 201T] for underground and surface mining from 1932 to 1942 (DO132-42). In order to estimate waste accumulated prior to 1959, the waste-to-ore ratios from the 1959 to 1976 period were plotted vs. time and line-fitted by regression analysis (Figure 1). Unfortunately, the extrapolation of the line to years prior 1959 approached zero in 1954 although surface mining began in 1950. Therefore, a waste-to-ore ratio of 8:1 was used for the period of 1950 to 1959 based on ratios estimated by Clark (C174). The waste to-ore ratios for 1976 to 1978 were estimated using the line established in Figure 1. By using waste-to-ore ratios and ore production data, the cumulative waste and ore production for both surface and underground uranium mining is estimated to 1978 (Table 2). The estimated cumulative waste from uranium surface mining for 1950 to 1978 is 1.73 x 109 MT. A crude estimate of the waste accumulated at the model inactive surface mine can be made by dividing the total waste produced to 1978 by the number of inactive mines. This, however, overestimates the waste tonnage because some of the contemporary wastes are being produced by active mines, and the waste accumulated at newer mines has increased in recent years. To adjust for this overestimate, we assumed that all mines operating in 1970 will be inactive by 1978. This eight year period is approximately one-half the lifetime of a model

Jan 1, 1981

By O. M. S. Rodrigues

The kaolinite presence in bauxite ores increases caustic soda consumption during the digestion step in the Bayer process. Depending on the kaolinite content, the utilization of the ore in the Bayer process may be unfeasible. This investigation addressed the variables involved in kaolinite flotation through microflotation experiments in a Hallimond tube and zeta potential determinations. The tests were performed with a pure sample of kaolinite (96%). Five collectors were tested: Duomeen T (DT), cetyl pyridinium chloride (CPC), cetyltrimethylammonium bromide (CTAB), dodecylamine (DDA) and Flotigam EDA (EDA). Four of them performed well as collectors, at a concentration of 1x10-4 mol/L: CPC, CTAB, DDA and EDA. The kaolinite isoelectric point (IEP) was determined at pH = 4.6. The IEP was shifted towards higher pH values in the collectors? presence, indicating specific adsorption onto the mineral surface.

Jan 1, 2011

By D. A. Poukhovski

Two integral components of the 30 CFR 48 training requirements mandated for new miners, newly employed experienced miners, and the annual refresher training of all miners are hazard recognition and prevention of accidents. In these categories, instruction shall include the recognition and avoidance of hazards present in the mine, and a review of accidents and their causes. Unlike instruction preparation for fact-based material, program development for hazard recognition places a particular challenge before safety-training specialists because they are often limited in their ability to adequately gauge the trainees' levels awareness prior to training. Further, they must also assure that the training is relevant, and it is presented in a thought-provoking manner. Computer-based instruction is particularly well suited for assisting trainers in developing hazard-recognition topics because it can be used in pre-training and post-training modes for assessment of training effectiveness, in addition to use as a presentation tool. Therefore, this paper will present a recent approach developed at Penn State to apply this technology for assessment and instruction of accident prevention through hazard recognition, with an application prepared for surface coal mines.

Jan 1, 1997

By Francis S. Kendorski

INTRODUCTION Caving offers the lowest cost per ton of any large-scale mining method, but its successful application demands an ore body that conforms to several rigid requirements. The deposit must be of wide areal extent, massive and not spotty in ore values, and insensitive to ore dilution. It must also be a rock mass that breaks up readily. There are only three active caving operations in the US-Climax, Henderson, and San Manuel-but caving methods have recently taken on new importance as deeper lower grade mineral occurrences and ore bodies are found. These deposits are too deep for surface min¬ing methods, and too low grade to support any type of underground mining except a bulk method such as caving. Announced discoveries or indications that may be amenable to caving include: Climax's Mt. Emmons molybdenum discovery in Colorado; Molycorp's Goat Hill molybdenum prospect in New Mexico; the Phelps Dodge molybdenum deposit in Beaver County, UT; Arizona copper occurrences such as Asarco's Sacaton, Hanna's Casa Grande, Noranda's Lakeshore, and Ken¬necott's Safford; Anaconda's suspected deep copper de¬posit in Butte, MT; Anaconda's Carr Fork, UT, deposit; and perhaps others. CAVABILITY'S ROLE IN FEASIBILITY STUDIES Caving is a system of underground mining which removes support from underneath an ore body. As a result, the rock mass fractures, fails, and flows vertically downward by gravity to be collected in previously ex¬cavated funnels. Types of ore that have been mined by caving include molybdenum, copper, iron, nickel, as¬bestos, and diamonds (Julin and Tobie, 1973). It is primarily a large-scale method, with production rates of more than 45 300 t/d (50,000 stpd) having been achieved. However, the initial capital investment before return is very high, often in the hundreds of millions of dollars. The cavability of an ore body or mineral occurrence is a critical item in the feasibility study of a proposed mine, not only from the point of overall minability, but from the point of impact on other costs such as blasting, loading, hauling, crushing, and grade recovered. Aside from the often-asked question of, "Will it or will it not cave?" the real questions are, "Can we afford to make it cave, carry the rock away, and extract the mineral?" The last is not a topic of this chapter, but the first two are. The cavability of an ore deposit or mineral occur¬rence is based on many things, but clearly, if a large enough area is undermined, any rock mass will cave. The result could be a violent collapse as occurred at Urad, CO (Kendrick, 1970), or perhaps the rock mass will cave beyond the ore boundary. Another unfavor¬able result could be ore blocks that are too large for the equipment and orepasses to handle without considerable secondary blasting. Weak rock with numerous fractures may produce a very fine ore when it caves, resulting in dilution and ground control problems. DETERMINING STRUCTURAL DOMAINS It has long been recognized that the geologic nature of an ore body is important to cavability (King, 1946). Such items as weak rock material, intensity of fractur¬ing, and severity of faulting all contribute to the success of a caving operation, and information regarding these is required as a minimum for the cavability determination. In practice, the rock mass-defined as the blocks of intact rock together with the intervening fractures, joints, faults, bedding planes, and other discontinuities-that contains the ore body, as well as the surrounding and overlying rock, must be examined in a systematic and detailed fashion. Surficial geology maps must be pre¬pared, exploration holes drilled, and core logged for en¬gineering information. The fracturing of the rock mass must be studied to ascertain the three-dimensional dis¬tribution of fractures and their characteristics, and faults must be located and described. The strength and other mechanical properties of the rock material, the fracture surfaces, and the fault filling materials must be tested and reported for later use by designers and planners. With this basic information and an understanding of the geologic setting, the rock mass can be divided into one or more structural domains which tend to behave similarly in response to engineering activities (Robertson and Piteau, 1970). One must keep in mind that the determination of the structural domains goes beyond the geologic units present. Several lithologic units may be lumped together, while a single lithologic unit can be divided into multiple domains. Major faults often form their own domain, and the direction of engineering ac¬tivity-for example, cave advance to the north rather than the south-may alter rock mass behavior, resulting in different domains. As an example of the detailed rock fracture map¬ping required for such studies, the structural domain determinations at the Climax mine (Kendorski, 1973) are shown in Fig. 1. The circles are Schmidt equal area projections of the three-dimensional attitudes of frac¬tures (Ramsay, 1967) mapped in detail at various rock exposures. The attitude of fractures is important to the cavability determination since it dictates the directional behavior of the rock mass as it fails, and determines the effectiveness of arching, keying, and rock block inter¬locking. Low-angle fractures must be present to allow movement of the rock in the vertical direction during undermining (Mahtab and Dixon, 1976); if low-angle planes of weakness are absent, the rock mass may arch with a keystone effect, rather than moving vertically downward.

Jan 1, 1982

By Joseph Cervik

Common methods of controlling gob gas in U.S. nines are by means of ventilation of gob areas and gas drainage through surf ace boreholes. Costs of drilling surface gob holes increase as deeper coalbeds are mined. Where gob holes cannot be drilled because of topography, ventilation is the only means of control. Even then, sufficient air may not be available to dilute methane in the bleeder entries to acceptable levels. Thus, new methods of gob gas control need to be developed that are independent of surface topography, and of the mine ventilation system, and less costly than present systems. Except for slight variations in procedures and equipment, Great Britain, West Germany, France, Belguim, Poland, and Czechoslovakia use a common methane control method that is different from the system generally used in the United States, This Bureau of Mines paper reviews European mining methods, mining conditions, and methane control technology and discusses their applicability to U.S. mines.

Jan 1, 1979

By Dru Brown

More than 150 Mt (165 million st) of material crashed down at the Bingham Canyon Mine (Rio Tinto/Kennecott Utah Copper) near Salt Lake City, UT on April 10, 2013. The mine, one of the largest openpit mines in the world, ceased operations and evacuated personnel prior to the slide when it was discovered that material was moving at a rate of 5 cm/d (2 in./day). The slide destroyed the mine?s visitor?s center, buried several pieces of large mining equipment and severely hampered production. The Kennecott Utah Copper Corp. immediately began to assess the damage and look for options to reestablish operations. The highly unstable ground ? emphasized by another minor slide in September 2013 ? makes any cleanup efforts extremely dangerous. With terrain too dangerous for human operators, Kennecott was forced to look for alternatives that would help the company work on the treacherous slopes of the landslide while also keeping personnel safe.

Jan 1, 2014

By Stanley M. Moos

In reviewing available vacuum filtration equipment in this paper, several types of filters have been included which are probably not familiar to operators in the mining industry. However, it was felt that these units might be of interest in the event that an application should arise for the filtration of a product in the future that does not exist today. In addition, exposure of our industry to equipment used in other industries might have a tendency to be thought provoking and perhaps lead to the development of equipment and/or applications in our industry which do not necessarily exist at this time. Most innovations in filtration equipment have been confined to the improvement or design change of components and accessories, particularly reflecting the availability of materials of construction that have been developed. Recent developments in the application of horizontal belt filters have been innovative. The application of this unit as a substitute for or an adjunct to thickeners in a CO circuit can certainly be innovative and perhaps provide a basis for reduction in capital and operating costs in this area. For example, mill tails are generally pumped at the highest possible density that will adequately flow. Tailings ponds and dams with their attendant design requirements are based upon this estimated water volume. Availability of a much dryer, non-flowing filter cake opens up several new options for disposal. Considerable cost savings could result in the design and planning of disposal areas for containing dryer material. . No attempt has been made in this paper to provide a manual for the operation of all of the many types of equipment that are available. Rather, the paper tries to present an overview.

Jan 1, 1978

By A. J. Abraham, K. E. Seitz, J. D. Humphrey

Caterpillar has led the way for sound reduction in off highway trucks (OHT) used for mining. In 2000 Caterpillar introduced the 793CXQ sound reduction OHT (Figure 4) to meet local noise level demands in the Hunter Valley near Sydney, Australia. The sound level of the mining equipment in the Hunter Valley is being reduced to pre-serve the quality of life for the residents of the area. To meet the levels established required a major redesign of the 793C, as a result the sound power level was reduced by 9 dB (A), which is a less than 1/8the original sound level.

Jan 1, 2004

By Raj K. Rajamani, Samira Rashidi

Wear is an extremely important topic when considering high-pressure grinding rolls (HPGR) for any new application. Given the inevitable variations in ore properties throughout a mine’s life, it is difficult to predict the effect of material and operating conditions on the wear parts: specifically, the HPGR rolls. However, the possibility of continuous scanning of rolls provides ample information to review the wear pattern and ways to optimize it. In this regard, as part of a broader investigation, the feasibility of in-line scanning of HPGR rolls in a laboratory-scale HPGR is studied and presented. The choice of scanners and methods adopted to achieve high-level accuracy for determining wear is discussed in this paper, and the inherent variability affecting the measurements is evaluated.