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By Glenn Mongillo

Discrete Element Method (DEM) software has been successfully used to simulate various machine/soil interactions and provide insight for industries such as mining and bulk material processing. This paper will investigate typical calibration techniques used in particle models for DEM simulation and physical calibration experiments with soft ground TBM cutting tools to incorporate parameters such as tool drag forces that contribute to required TBM torque. With a well calibrated DEM model, it is expected that TBM simulation results will be more meaningful and provide better insight into TBM performance, power requirements, cutting tool placement, and overall cutter head design.

Jun 13, 2021

By James P. Cooney

What is required for the mining industry to grow and prosper in a politically challenging world? The answer to this can be summarized as “the industry’s three priorities.” The first priority is gaining access to the world’s mineralized jurisdictions. The second is establishing a measure of security and predictability in government treatment of mining. Confidence in the stability of the fiscal and legal framework within which mining operates is necessary to encourage the investment of large amounts of capital in mine development. The third priority is sustaining the industry’s welcome during the long term in those jurisdictions worthy of investment.

Jan 1, 1996

By Panshi Xie, Yingyi Zhang, JIANJIE DUAN, Shenghu Luo

The most important safety aspect associated with great mining height in steeply dipping coal seam mining is the stability and control of the roof. When soft coal and hard gangue make up the immediate roof of a working face, the soft-coal interlayer plays a significant role in gangue damage and can cause problems such as roof collapse in front of the support, collapse of partial area supports and other problems that can affect the stability of the supports and the surrounding rock system. This study found that the first weighting step of a multigangue roof is larger than that of a nongangue roof, but periodic weighting steps are similar. The overburden collapse height is lower in a multigangue roof than in a nongangue roof due to the buffering and supporting function of the collapsed gangue. Failure of the coal interlayer is the key factor in the collapse of multilayer gangue. The limited load of the interlayer and maximum resistance of the support is concluded by the hard gangue and soft coal interlayer mechanical model. The maximum resistance of the support increased with the dip angle of the seam and burial depth. Certain measures are proposed to control the stability of the gangue roof, including zoning control of the mining height and resistance and advancing the support while maintaining roof contact, thus ensuring the integrity of the support and surrounding rock system.

By Rohan Fernando, David P. Snyder, John F. Burr, Susan M. Moore

"The Mine Improvement and New Emergency Response Act of 2006 (MINER Act Public Law 109-236) was passed by Congress in response to three major underground coal mine accidents in the United States that claimed the lives of 19 miners. The Act resulted in substantial changes in the underground coal industry relative to the use of technology for mine escape, rescue, disaster response and other areas where the lack of these technologies contributed to the fatalities caused by these tragedies. This year marks the 10th anniversary of the MINER Act, which makes it an opportune time to reflect on the events that led to its passage, the changes that have been made since then, and the work that remains to be done.As discussed below, the last decade has demonstrated tremendous cooperative efforts among mining operators, technology innovators, labor, The National Institute for Occupational Safety and Health (NIOSH), the U.S. Mine Safety and Health Administration (MSHA) and state regulators, resulting in substantial improvement of the technologies used for escape and rescue and noteworthy progress toward meeting many of the goals of the MINER Act. While the MINER Act and this article pertain primarily to coal mining, many of the technologies are equally applicable to any underground mining and have already found some acceptance outside of coal.Technology gaps targeted by the MINER ActThe MINER Act addressed several technology challenges:• Problems with donning and switching between self-contained, self-rescuers (SCSRs).• Poor visibility in smoke.• No wayfinding assistance for escape from the mine.• Limited breathable air supply.• Inability to locate trapped miners.• Inability to communicate with trapped miners.• Failure of mine seals."

Dec 1, 2016

By C. L. Wilsey, K. M. Oakes, W. J. Reich, M. J. Protani

The time frame required to complete the National Environmental Policy Act (NEPA) process for a new mine, or for the expansion of an existing mine, can range between 9 months to 24 months, or more. The time frame will vary depending on whether an Environmental Assessment (EA) or an Environmental Impact Statement (EIS) will be completed. Completing properly designed baseline studies to collect natural resource data to support the EA or EIS prior to the start of the NEPA process can shorten this time frame. The two year natural resource baseline study completed by Homestake Mining Company for the Ruby Hill Mine, located in Eureka County, Nevada will be used as the case study to describe how properly designed and executed natural resource baseline studies streamlined the NEPA process.

Jan 1, 2001

By M. A. Trevits, G. W. Luxbacher, L. D. Patts

"It is almost a given that post-disaster mine conditions will have compromised the mine ventilation system, resulting in a hazardous atmosphere in portions of the mine, and often complicated travel through debris fields and roof falls. Robotic technologies provide the opportunity to gather valuable information to assist decision making or lessen exposure to dangerous conditions. MSHA's Mine Emergency Operations Division (MEO) has utilized a fully permissible mine robot, the V2, for a number of years, constantly updating the unit as new technologies became available. The National Institute for Occupational Safety and Health, as part of the MINER Act Extramural Contract Program, examined the need for additional robotic units and ultimately funded three different types of prototype technologies: two robots, the Snake Robot and the Gemini-Scout, and a mine rescue robotic assist vehicle known as the ""Mule"". The Snake Robot is designed to be lowered through a borehole and to conduct surveillance (gas monitoring, video and audio) in the immediate vicinity, while the Gemini-Scout, designed to be deployed in the mine opening, serves as a more mobile and agile exploratory tool as compared to the MSHA V2 robot. The Mule was developed in response to needs expressed by mine rescue teams for a versatile remotely operated support vehicle and it will move from prototype to MEO utilization in the near future. This paper describes the development of the robot prototypes and discusses their limitations in the prototype stage, possible enhancements and potential applications, as well as the utilization of the Mule. INTRODUCTION The conditions in a coal mine may be dramatically altered after a mine fire or explosion. For example, the ventilation system may not be functioning correctly as control devices may be compromised or damaged beyond repair. The visibility in the mine opening may be limited due to accumulated smoke and dust. Roof support systems may be damaged or no longer functional. Equipment and materials may be strewn about the mine opening. Debris fields, blocked openings, roof falls, flooded areas, gas accumulations and active burning make it very difficult or impossible for those managing the post-event emergency to permit mine rescue teams to enter the mine to conduct search and rescue operations. With the evolution of robots and robotic assist technology there has been a proliferation of purpose-built units for the military, police and law enforcement agencies, urban search and rescue and those contending with hazardous environmental conditions. In each case, the technology used is designed to limit human exposure to the unsafe conditions or to provide access to areas under difficult conditions. For example, a specially-designed marine robot has been deployed into the damaged core of the Japan’s Fukushima Daiichi Nuclear Power Plant to assess the conditions of the containment vessels, where melted fuel is believed to have accumulated. Human access to the area is prohibited due to dangerously elevated levels of radioactivity [1]. Multiple robots were deployed in Amatrice, Italy, to assist in the response after the 6.2-magnitude earthquake devastated the town. The robots were used to explore two medieval churches that were severely damaged and deemed too dangerous for human entry [2]. Tactical robots are regularly used by police and law enforcement agencies when the conditions of the emergency place intervening officers directly in harm's way [3]."

Jan 1, 2018

By Yehia M. Youssef, Nourhan Moukhtar, M. H. Abdel-Aziz, Ibrahim Hassan

Copper was recovered from copper sulfate solution in a batch-recycled galvanic reactor operated under forced convection with the generation of electrical energy during the cementation process. The divided galvanic cell consisted of parallel copper and zinc plates. The mass transfer rate and the amount of electrical energy generated were found to be directly proportional to the solution flow rate and the initial concentration of metallic ions and inversely proportional to the distance between electrodes. The experimental results were expressed in terms of a dimensionless correlation including all parameters. The wastewater treatment presented herein cell can be utilized to recover many soluble heavy metal ions from solution with high efficiency.

Oct 2, 2020

By James Wm. White

Computer-based mine management systems are being used in many surface mines to assign haul trucks, track equipment and manage information. Advances in digital communications allow these systems to be used in underground operations. Underground mine management systems help maximize production by providing gains in equipment and manpower use, drawpoint equalization in block caving operations, preventive maintenance and safety. Current systems use allocated or "locked" train and load-haul-dump (LHD) dispatching. Allocated dispatching rarely optimizes open pit product' on. But it offers an efficient mode of operation underground and where options are more limited. The primary objectives of underground mine management systems are to maximize production and mini¬mize contention time through allocated train, truck or LHD dispatching, traffic control, equipment monitoring and comprehensive reporting. The main components of an underground mine management system include: ? A central computer (personal computer or worksta¬tion) in a central control center. It sends instructions to train, truck or LHD drivers and allows dispatcher interaction. ? A field computer system (FCS). This consists of a touch-screen graphics console (GC) and mobile hub - on each train, truck or LHD to receive and display instructions from the central computer and accept driver input. ? A data radio network based on leaky feeder (data, voice, video) or microcell radios (data only) and advanced token-ring technology. This passes information between the central computer and the FCSs. ? Radio frequency (RF) tags mounted at boxes, weigh bridges, tips and rim tunnel main haulage ways to locate trains or LHDs (Luke, 1993). Such a management system must be in place before implementing computer-based dispatching (Vagenas, 1991) for production optimization.

Jan 1, 1997

The authors provide a discussion of the paper, ?Coal workers? pneumoconiosis prevalence disparity between australia and the united States,? a peer-reviewed paper that appeared in the technical papers section of the July 2012 issue of Mining Engineering magazine. The original authors, G.J. Joy (gjoy@cdc.gov), J.F. Colinet (jcolinet@cdc.gov) and D.D. Landen (dlanden@cdc.gov), respond.

Jan 1, 2013

By Michael V. Wolski, Ryan O. McCarter, Kenneth A. Johnson

"The Central Subway is Phase 2 of the San Francisco Municipal Transportation Agency’s (SFMTA) Third Street Light Rail project and will extend the existing Phase 1 initial operating segment from its current connection to the Embarcadero line at Fourth and King streets along Fourth Street to Market Street, under the Bay Area Rapid Transit (BART) and Muni Metro tunnels and then north beneath Stockton Street to Chinatown (Fig. 1).Total new track to be constructed as part of the Phase 2 work consists of approximately 734 m (2,410 ft) of surface track and 2,636 m (8,650 ft) of tunnels. The tunnels were constructed as twin, singletrack bores by two tunnel boring machines (TBMs) (Johnson, 2014) moving north from the southern end of the launch box under the I 80 freeway between Bryant and Harrison streets. North of Chinatown Station the TBMs continued another approximately 683 m (2,240 ft) to a retrieval shaft near Columbus Ave. at Washington Square. The project also includes five cross passages to connect the two tunnels, and three underground stations (the Yerba Buena/ Moscone Station, Union Square/Market Street Station and Chinatown Station.)Excavation of the twin tunnels was performed with two TBMs, with both TBMs driving northward from the launch box. TBM excavation was performed such that the location of the machines was staggered to separate the active excavation faces by a minimum of 91 m (300 ft) between headings. This minimum separation was maintained until the first TBM arrived at the retrieval shaft plug, at which time the separation requirement was relaxed.Excavation began with the “southbound” (SB) tunnel which will ultimately accommodate the southbound TBM light rail trains followed by the second TBM in the “northbound” (NB) tunnel. With the completion of the drives in June 2014, cross passage excavation then began and was completed in April 2015. Overall, construction of the Central Subway tunnels was a success considering the nature and complexity of the project. Additional details of the completion of the Central Subway tunnels are presented in another paper from the RETC 2015 conference (Leong et al., 2015)."

Jan 1, 2015

By Gamal Rashed, Zorica Radakovic-Guzina, Khaled Mohamed

"Underground coal mines use mechanical bolts in addition to other types of bolts to control the rib deformation and to stabilize the yielded coal ribs. Limited research has been conducted to understand the performance of the mechanical bolts in coal ribs. Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted this work to understand the loading characteristics of mechanical bolts (stiffness and capacity) installed in coal ribs at five underground coal mines. Standard pull-out tests were performed in this study to define the loading characteristics of mechanical rib bolts. Different installation torques were applied to the tested bolts based on the strength of the coal seam. A typical tri-linear load-deformation response for mechanical bolts was obtained from these tests. It was found that the anchorage capacity depends mainly on the coal strength. Guidelines for modeling mechanical bolts have been developed using the tri-linear load-deformation response. The outcome of this research provides essential data for rib support design.INTRODUCTIONThe design of rib bolting in U.S. coal mines is based on a trial-and-error process, which is insufficient to eliminate injuries and fatalities caused by rib falls. In the last 10 years, rib failures have resulted in 17 fatalities, representing 52% of the ground-fall fatalities in underground coal mines in the United States (MSHA, 2018). Recently, NIOSH researchers surveyed 90 sites in 14 underground coal mines in the Eastern United States and found that 11 mines are bolting coal ribs, with 4 of those mines using the conventional mechanical bolts and the others using fully-grouted bolts. NIOSH researchers are developing an engineering design procedure for rib support. Pull-out test programs for mechanical and grouted rib bolts were conducted to understand the rib control mechanisms of rib bolts. Only the test results of mechanical bolts are presented in this paper.Mechanical bolt (or point-anchored bolt) is a tensioned bolt anchored down the borehole with a mechanical expansion shell or a resin-grouted medium (Peng and Tang, 1984). The mechanical anchor bolt consists of a plug, a shell anchor, a headed bar with the top end threaded, a bearing plate, a hardened washer, and occasionally a friction-reducing washer. The shell anchor can be either standard or bail type (Figure 1). The standard type shell is held in place by a nut, while the bail anchor uses a strap to hold the shell in place (Peng, 2008). The diameter of the bar is generally 16 mm (? in) for the #5 bolt or 19 mm (6/8 in) for the #6 bolt. The diameter of the hole that the bolt is inserted into must be carefully controlled, since an oversized hole can result in poor anchorage (Moss, 1971). The anchorage is obtained by applying torque to the bolt head, which in turn pulls the plug down in the shell and expands the serrated leaves against the sides of the hole-wall. In the resin-grouted anchor, the resin replaces the mechanical expansion shell at the end of the hole. The anchorage is achieved by bonding between the resin, bolt, and the hole-wall."

Jan 1, 2019

By Christopher Mark

Area wide pillar failures, or “squeezes,” were once fairly common in underground coal mines. While rare today, they do occur. This paper describes seven case histories that were investigated by MSHA Technical Support. They occurred across the range of US coalfields, in both longwall and room-and-pillar mines, and involved development mining, pillar recovery, longwall panel extraction, and multiple seam interactions. Significant lessons from each are discussed.

Jun 25, 2024

By Todd Kilduff, Paul Wilkinson

Microtunneling is rarely a straight forward “business as usual” endeavor. More often than not, these projects take twists and turns that require on the fly, out of the box solutions to get the project completed. This paper is a case history of a 63-inch diameter, Permalok, microtunneling project, extending nearly 700 linear feet under a hill forming the left-hand abutment to an earth embankment tailings dam. The job had three major and unexpected challenges that required unorthodox solutions. Challenge #1— Face Configuration: The Santiago Formation, a cemented sand formation with widely varying strengths, presented a challenge to configuring the face with regards to the number and length of pics and cutters. Subtle differences in type and size of the tooling had a big impact on the performance of the machine. Challenge #2—Eccentric Loading: Issues at the launch shaft with the Permalok pipe adaptors caused eccentric loading on the casing pipe. This issue resulted in overstressing and breaking of several pipe joints that ultimately led to seizure of the tunnel. Challenge #3—Back-tunnel Excavation and MTBM Recovery: There were many detailed considerations into excavating a recovery tunnel to retrieve the MTBM, especially being under a high hazard earth embankment dam.

Jun 13, 2021

By M. Trim, Y. Sun, D. Tepavac, A. Kumar

Configuration of Rozelle Interchange Project’s ventilation system required design and construction of some of the largest and tallest underground civil caverns attempted in Australia. The paper focuses on the technical challenges of designing these caverns within a heterogeneous, generally weak sandstone under highstress conditions while providing a construction sequence that would align with the contractor’s preferred techniques and schedule. Various construction techniques were investigated, but ultimately an observational approach relying on a construction sequence and specialized instrumentation met both the designer’s and contractor’s requirements. Relevant data obtained from excavations and the construction monitoring program are presented within.

Dec 1, 2022

By Harvey W. Parker

Our industry has developed to the skilled, experienced and productive industry that we now enjoy as a result of the visions of great engineers throughout history, but, in particular for their visions in the last 1 centuries. Unfortunately for our forefathers, the technology lagged so far behind that these exceptional visions could not be realized for decades, sometimes for a century. All that has changed in recent time and many bold and visionary projects can now be constructed and operated because of dramatic advances in technology. Before, say, 1950, tunnel technology developed very slowly. However, technology is now developing at such a fast rate that planners and decision makers are challenged to stay ahead. Moreover, new technology will develop during the lifetime of any project that can dramatically improve under-ground space projects. One of the best examples of this technological advancement is that of closed-face TBMs which now make tunneling feasible in previously impossible ground conditions. Since it usually takes a decade or more to plan, overcome environmental and political issues, construct, and put into service major projects, planners and designers are challenged by the changes in technology that occurs during the long time span of planning and construction. This is particularly true of large infrastructure projects such as transportation, water and wastewater systems and other major underground schemes. Also, since the serviceable life of many of these tunnels is often over one century, planners must consider not only lessons learned from the past but also what new concepts and innovations may develop over an extremely long time. These and other issues create a great challenge to planners and illustrate the great importance of careful but creative vision and flexibility during planning of long-term tunnel and underground space projects.

Jan 1, 2008

By D.G. Osborne

Each month abstracts of the papers selected for the Annual Bound TRANSACTIONS Volume will appear on this page. Since the Annual Bound Volume will not be published until the spring of next year, this will give people an opportunity to order copies of the papers earlier. If you would like copies, fill out the coupon below and return it to SME-AIME. Each copy will cost

Jan 1, 1985

By M. E. Gershon

Conventional methods of drill hole site selection are reviewed briefly. Two approaches using geostatistics are then discussed, both of which have been shown to yield improved results. Finally, a branch and bound algorithm is described which will select the best locations for drilling from a user specified number of possible drill sites. Two options are discussed. First, the user can specify a maximum drilling investment or a maximum number of drill holes and the program will select the locations yielding the minimum estimation variance. This amounts to getting the most for a given investment. Alternatively, a maximum tolerable estimation variance can be specified and the program will select the number and location of the drill holes to obtain the desired information at a minimum cost. Another benefit of the approach is the quantification of the tradeoffs between investment and information obtained.

Jan 1, 1985

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 A. House

Newmont Mining Corporation owns and operates the Phoenix Mine near Battle Mountain, Nevada, USA. The existing milling facility has operated since 2006. Following the startup of the milling operation, and coupled with the upswing in the copper market, Newmont realized that Phoenix needed a process option to treat lowgrade transition and oxide copper ores. This meant that potentially revenue generating ore was being mined as waste. With no system in place to treat the transition and oxide copper, work began to determine the most feasible approach. After evaluating multiple options, the flow sheet was set for a run-of-mine (ROM) heap leach pad and solvent extraction/electrowinning plant (L-SX/EW). This paper will discuss the synergies and challenges of developing a copper L-SX/EW plant at the Phoenix copper-gold mill.

Jan 1, 2010

By Igor Gonzales G.

The Southern Peru Copper Corp. (SPCC) recently built an integrated copper project consisting of dump- and heap-leaching operations at its mine complex in Peru. The pregnant leach solution (PLS) containing the solubilized copper from the leaching operations is processed in a new solvent extraction/electrowinning (SX/EW) facility to produce high-purity cathode copper. The dump leaching and SX/EW facilities are located near the Toquepala mine site. The crushing and heap-leaching operation is located at the Cuajone Mine. The pregnant leach solution from Toquepala and Cuajone is pumped 35 km (22 miles) to the SX/EW plant at Toquepala. The SX/EW plant consists of three trains of solvent extraction (SX), a tank farm area and an electrowinning (EW) facility. The solvent extraction plant has a total PLS flow capacity of 3,210 m3/hr (113,360 cu ft/hr). The electrowinning facility has an expected long-term production capacity of 97 t/d(107 stpd) or about 35 kt/a (38,500 stpy) of cathode copper. However, present production exceeds the expected long-term by about 20%.

Jan 1, 1996