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Surface subsidence that results from longwall mining can be large magnitude and can affect significant areas. Conventional methods for subsidence monitoring include leveling, global positioning system (GPS), and photogrammetric surveys. Remote sensing techniques, including aerial LiDAR, terrestrial laser scanning, and satellite-based differential interferometric synthetic aperture radar (DInSAR), are also used to measure deformation associated with subsidence. DInSAR data are different than data from conventional subsidence surveys. Images capture data over large areas (hundreds of kilometers), and each pixel (data point) in an image quantifies the average displacement over an area of square meters. DInSAR data can have fairly high time resolution; imaging periods typically range from weeks to months.

Jan 7, 2020

The prediction and control of ground deformations due to underground mining are important considerations in the permitting, planning, and monitoring of coal mining operations. The prediction of mining-induced ground movements using the influence function method is a mature technology and is widely used in many coal basins around the world. Such movements mainly include subsidence, horizontal displacement, and horizontal and/or ground strain. Predictions can be accomplished using regional subsidence parameters and site-specific data.

Jan 7, 2020

By R. E. Mitchell

Environmental Impact Assessment (EIA) is the accepted method for evaluating proposed mining and other industrial projects to obtain regulatory approval and to help companies plan for responsible development. Another evaluation system becoming increasingly more common for proposed projects is the Environmental, Social and Health Impact Assessment (ESHIA). An ESHIA differs from an EIA for its more comprehensive and inclusive approach to evaluate potential impacts on public health, and its ecosystem services approach to assessing biodiversity impacts. An ESHIA may also be required by certain lenders for financing major projects. Conducting an ESHIA for a proposed mining development is not without its challenges, with costs, scheduling, regulatory concordance and other constraints to be considered. This paper examines some benefits and challenges of ESHIAs and summarizes lessons learned using a case study approach.

Jan 1, 2012

By M. A. Reyes, L. Yan

Heat and humidity buildup withn refuge alternatives (RAs) may expose occupants to physiological hazards such as heat stress. The Mine Safety and Health Administration (MSHA) regulations require RAs in underground coal mines to provide a lifesustaining environment for miners trapped underground when escape is impossible. RAs are required to sustain life for 96 h while maintaining an apparent temperature (AT) below 95 °F (35 °C). The National Institute for Occupational Safety and Health (NIOSH) tested a 10-person tent-type RA, a 23-person tent-type RA, and a 6-person metal-type RA in its underground coal mine facilities to investigate the thermal environment over a 96-h period. The test results showed that mine air and mine strata temperatures surrounding an RA occupied by simulated miners (SMs) increased over the 96-h test period. The test results suggest that RA manufacturers should consider this increase in temperatures when calculating and evaluating RA components during surface and laboratory tests. The findings can equip stakeholders with additional considerations for calculating the interior heat and humidity temperature profiles for occupied RAs not tested in situ.

By Kevin G. Stricklin

Introduction Continuous monitoring techniques have been used in the US and abroad for many years. A continuous miner has a monitor that measures methane and automatically gives a warning if the methane exceeds 1%. It deenergizes the continuous mining machine automatically at a maximum concentration of 2%. Main fans are also continually monitored to ensure operation. Alarms may also be given at a remote location should a fan slow or stop. The systems being developed can continuously monitor various gases and equipment throughout the mine and transmit pertinent data to a surface monitoring station. At this station, conditions throughout the mine can be monitored and, in some instances, controlled. These are known as Mine Wide Monitoring Systems (MWMS). History The use of environmental monitoring systems began in 1976 when a federal court approved the petition of modification to use belt air at the face. The first mine to receive a modification did install a system to supplement existing safeguards. Later, the Mine Safety and Health Administration (MSHA) and the US Bureau of Mines (USBM) conducted tests dealing with the use of belt air. Findings from these tests are being used to set guidelines as requirements of a petition. These requirements include: • Velocity of air has to be 0.25 to 1.5 m/sec (50 to 300 fpm); • Monitors will be installed at each belt drive and tailpiece and at intervals not to exceed 610 m (2000 ft); and • An alarm level of 10 ppm, above the ambient level is appropriate. The early uses of environmental monitoring could only be used outby the last open crosscut. That may be a reason for an initial slow growth of these systems. In June 1982, MSHA began evaluating systems that could be used in returns to ensure that monitoring systems being used in areas where permissible equipment is required does not of itself pose an explosion hazard. This is known as the Mine Wide Monitoring Systems Evaluations and Sensor Classification program. The evaluations and classifications granted are based on electric currents and voltages. Use of mine wide monitoring systems The environmental aspect of MWMS in today's coal industry deals with carbon monoxide (CO), methane (CH4), and air velocity. Just as all mines are different and encounter different problems, the MWMS are diverse and can be used to provide necessary data in all areas of coal mines. Mine operators in an ultragassy seam, for example, may be concerned with monitoring methane, while a mine that used diesel equipment may want to continuously monitor for diesel contaminants. In a mine with roof fall problems, airflow monitors may be helpful as an indication of whether the air is flowing in its normal course and at its normal volume. Today's MWMS can monitor any or all of these parameters. Most systems can be expanded as mining needs require. For example, a mine is now being monitored for methane and five years from now CO monitoring would help increase safety. It may be possible to use the same system by adding additional equipment. In the US, 30 environmental monitoring systems were installed from May 1985 through May 1986. In 1984 and 1985, there were 38 and 44 environmental monitoring systems in operation, respectively. Due to mine closings, 11 of these are no longer in use. However, the number of mines using environmental monitoring systems increased to 63. Use of these systems are not limited to any geographic area or

Jan 9, 1987

By Forrest C. Neil, Clint J. Keifer

The pollution of our water supply, Lake Michigan, is a continuing threat so long as our overflows from combined sewers exist. The problems have become even more acute during recent years, due to the increase of paved area- which accelerates and enlarges the flows of storm water. After each storm, mixtures of raw sewage and storm water spill into our waterways. If the storm is too large for the drainage systems, the mixture backs up into our streets and basements. Under severe conditions, it may even become necessary to open the locks, and discharge the polluted water into Lake Michigan. Consider the scope of the problem, as shown in Figure 1. The area in which combined sewers exist is 375 square miles, located in the central parts of Chicago and 49 suburbs. There are an estimated 640 overflow outlets to the waterways, each requiring attention. The capacity of outlets tributary to the waterways has increased dramatically over the years. Each time a pocket of upstream flooding is drained into the channels, the problem of its rapid disposition increases. Another difficulty is that the bottom of our waterways is covered with a blanket of accumulated sludge, ranging in depth up to 3-feet. This material harms the water quality by depleting the supply of oxygen dissolved in the water ... a final

Jan 1, 1997

By Yi Luo, Jian Yang, Hua Jiang

Surface subsidence events induced by underground longwall coal mining operations can cause various disturbances to surface structures ranging from integrity and stability to functionality problems. Highway bridges, as a kind of special road construction that can only tolerate smaller movements and deformations than road pavements, are particularly susceptible to severe influence caused by subsidence-induced ground movements and deformations. However, based on accurate subsidence prediction and correct influence assessments, efficient and effective mitigation and remediation measures can be designed and implemented to ensure the continuous service of bridges, safety of the travelers and smooth mining operations. In this paper, based on the predicted final and dynamic surface movements and deformations, the techniques to assess subsidence influence on the integrity, stability and functionality of bridge structures (e.g., decks, beams, abutments, etc.) are presented. A number of mitigation measures to protect the bridge structures are recommended along with an actual application case.

By Bradford F. Townsend

A study was made on six collapses that occurred during large-diameter tunnelling through weak sedimentary rocks and soil using SES methods in three stages?top heading, bench and invert. The collapsed lengths are between 20 m and 277 m. The collapses were re-mined using essentially the same tunnel-ling method with larger excavation profiles to accommodate the designed remedial measures consisting of ground treatment, pre-support and stronger initial support/outer lining required to carry higher ground loads acting in the collapsed lengths. The paper presents information on the collapses and the design and execution of the remedial measures.

Jan 1, 2008

By L. W. Saperstein

Public Law (PL) 95-87 contains explicit demands for land use planning in its reclamation and designation sections. Both sections require recognition of local land use plans; however, they are not well integrated. Accommodation to these planning requirements affords an opportunity to create better links among local land use planners, the state's permitting authority and designation office, and mine designers. Mining companies should take a more positive interest in local land use plans and in resource inventories. States should consider handing down to local government the responsibility for accepting mine permit applications and designation of unsuitability petitions.

Jan 12, 1983

By Douglas Banks

Construction for the new 2.5 MGPD raw water intake project commenced December 2002. The project, initially designed as a 12' Ø concrete lined intake shaft,145' deep, with two offset 24" lake taps, 520' and 470' long was subsequently “value engineered” running the two lake taps through a single conduit. The offset for summer and winter pools was accomplished via a second shaft located at the lakes edge. Construction involved the use of blind drilling techniques for the shaft development and drill and blast techniques for the tunneling. All works were completed through extremely hard crystallized sandstone. The project came online August 12, 2004.

Jan 1, 2005

By F. Grajales Muñoz

The Ciénega project, now under construction by Peñoles group, is located in the mountains of northwest Durango, Mexico. The gold and silver deposits are found in a 4-km (2.5mile) long system of veins. An underground operation will be built. The planned 1 kt/ d (1100 stpd) process plant will contain a countercurrent cyanide circuit for oxide ore and a flotation circuit for sulfide ore. Considerable resources have been devoted to the development of infrastructure in the isolated location, as well as for the mitigation of environmental impacts. Startup is scheduled for the third quarter of 1994. Ciénega’s ore bodies consist of quartz veins containing gold, silver, lead and zinc values. The vein thicknesses vary from 2 to 10 m (6.5 to 33 ft) with a northwest trend and nearby vertical dip. Veins are hosted in Tertiary volcanic rocks. The district has intermittently been explored since 1971 by Penoles. After the third series of diamond drilling and direct development work on vein, Peñoles decided to begin project construction.

Jan 1, 1994

By Wayne E. Kilker, Michael J. McBride, William P. Levy, Thomas J. Lamb

Between 1989 and 2004 the Massachusetts Water Resources Authority (MWRA)constructed several major wastewater and water tunnels associated with three major projects in the Boston area of eastern Massachusetts. There were many similarities and differences in the bedrock conditions encountered and among the contractual approaches for these independent projects. Through a clarification of the approach similarities and analysis of the contract differences, this paper addresses and presents what are considered to be valuable lessons learned. In doing so, the paper follows the evolution of such disparate issues as contract conditions, baseline reports and dispute review boards. The authors believe that the lessons learned even represent what, in certain cases, could be referred to as “universal truths” that are intended to have application to the next generation of tunneling contracts.

Jan 1, 2005

By J. W. Davis

In the last few years major industrial companies have begun to realize the importance of Reliability as an enterprise strategy that, properly implemented, will improve financial performance. Typical results of an effective Enterprise Reliability Strategy include a 20% -50% reduction in maintenance cost accompanied by a 5% - 10%increase in real production capacity, with no capital investment in production equipment. One factor fueling the race to acquire and implement enterprise reliability is the pressure for companies to be increasingly cost-effective and competitive in global markets. In a recent study, Asset Productivity: The Next Wave, the Boston Consulting Group (BCG)stated that, “In order to compete for funds, companies must offer investor returns that are competitive with other opportunities. Alternative investments such as dot-com and others with non-traditional business models have raised the bar.” (APDF version of the study can be downloaded at www.bcg.com). BCG views asset productivity as the most powerful mechanism for increasing shareholder return. The author believes that the most effective way to increase Fixed Asset Productivity is to maximize asset utilization by increasing the Reliability of the Assets and the associated processes. Developing and implementing an ERS requires significant effort and knowledge. Most companies have difficulty finding a sufficient supply of these valuable commodities to implement an ERS Program internally. Many companies also struggle with figuring out how to get started and what direction to proceed.

Jan 1, 2003

By Chris Tattersall, Tomyuki Kudo, Peter Raleigh, Nestor Garavelli, Steve Redmond, Michael J. Lehnen

Twin bore running tunnels driven approximately 4,500 route feet by a Mitsubishi Heavy Industries (MHI) EPB Tunnel Boring Machine link the West Portal and East Portal on this complex Light Rail Project. One third along the way, the TBM arrives at the Beacon Hill Station which is the deepest underground “binocular” station of its kind in North America and then “walks-across” the station to be re-launched on the other side to complete the drive. This paper discusses briefly the layout and design considerations but then focuses more deeply on the approach by the Contractor to drive and supply the tunnel. The paper addresses the approach used to launch, re-launch and recover the TBM and touches briefly on muck volume control and monitoring plus settlement monitoring and the performance achieved. Also of interest is a unique solution to a difficult launch situation involving a secant pile tieback wall designed with several rows of double I-beam steel walers spanning the eye at the West Portal under the I-5 freeway.

Jan 1, 2007

By Malcolm Ross

The Reserve Mining Co., in the processing of taconite iron ore quarried from the Peter Mitchell Pit, deposited the finely crushed waste rock into Lake Superior near Silver Bay Minnesota. In the early 1970s The U.S. Environmental Protection agency filed a lawsuit against Reserve Mining Co., asking the court to force the company to stop dumping into the lake. On April 20, 1974, after a lengthy court battle, the U.S. District Court concluded that the Reserve Mining discharge into Lake Superior violated federal and state pollution laws and thus ordered Reserve Mining Co., to halt the lake disposal of taconite tailings. At the time many feared that some of the mineral particles contained in the tailings (alleged to be asbestos or asbestos-like) would cause human health problems. This Conference was thus convened to readdress the problem of the mineral content of the Biwabik Iron Formation and to whether any minerals contained in the ore could cause human disease. The four papers given in this session address the nature of the mineral particles in the taconite rock, the definition of the term ??asbestos?? and the history of the legal controversy over the possible health effects of certain mineral particles contained in the Biwabik iron range ores. Paper 1?Geology of the Biwabik Iron Formation and Duluth Complex Mark A. Jirsa, James D. Miller, Jr., G.B. Morey The Biwabik Iron Formation was a principal source of ore for the American steel industry during the 20th Century. The unaltered iron deposits, called taconite, contain approximately 30% iron and 50% SiO2. About 75% of the iron in taconite resides in the mineral magnetite, the remainder is largely in iron carbonate and several iron-silicate minerals.

Jan 1, 2007

By Gary E. Slagel

The year was 1974. The event - the United States Congress was embroiled over what issues should be included in the proposed national surface mining law. The question - what should be done with underground mines? The leading bills ultimately addressed the environmental impacts associated with underground mines including provisions to protect the surface from subsidence impacts. Amid the fears that this subsidence language might discourage underground mining, sponsors of the bill were asked to explain the meaning of the provision that read "to prevent subsidence to the extent technologically and economically feasible." Was this an attempt to limit mining that caused planned and controlled subsidence? Former Deputy Director of the Office of Surface Mining, Dean Hunt, reviewed some of these historical events in a 1985 presentation before the Eastern Mineral Law Foundation. He reported that in 1974 Congressman Morris Udall took the floor to respond to these concerns expressed by other members of Congress and the industry. Mr. Hunt cited Congressman Udall's July 10, 1974 Congressional Record statement: "The House bill contemplates rules 'to prevent subsidence to the extent technologically and economically feasible.' The word prevent led to fears expressed by the Secretary of the Interior Morton, that the effect would be to outlaw longwall mining, with its obvious subsidence ... in fact the bill's sponsors consider longwall mining ecologically preferable and it and other methods of controlled subsidence are explicitly endorsed." Further, the report that accompanied the front-running bill, HR11500, provided the following clarification on the issue of subsidence prevention: "It is the intent of this section to provide the Secretary with the authority to require the design and conduct of underground mining methods to control subsidence to the extent technologically and economically feasible in order to protect the value and use of surface lands. Some of the measures available for subsidence control include: (1) leaving sufficient original mineral for support; (2) refraining from mining under certain areas---or (3) causing subsidence to occur at a predictable time and in a relatively uniform and predictable manner. This specifically allows for the uses of longwall and other mining techniques which completely remove the coal." It is clear from the preceding statements that Congress considered the removal of all the coal and causing subsidence in a predictable and uniform manner to be equal to or better than leaving support coal and causing no subsidence. While the actual provision in the bills talked of preventing subsidence, a subsequent exception made it clear that the real intent was to control it. This is evidenced in the specific planned subsidence language that appeared in the bills and ultimately in Section 516 (b) (1) of PL95-87, the Surface Mining Control and Reclamation Act. It reads: "...adopt measures...to prevent subsidence ... except in those instances where the mining technology used requires planned subsidence in a predictable and controlled manner..." In spite of this historic record that supports controlled subsidence, something has been lost in the implementation. The primary focus by many regulators over the past few years has been on the "prevent" aspect irrespective of mining method being used. This has appeared to change the original intent of Congress from one of controlling subsidence to one of minimizing damage. The objective of this report is to review some of the current regulatory issues that impede full extraction mining and offer some suggestions on possible ways to deal with these issues.

Jan 1, 1986

By L. E. Beverage

In 2006, the Mine Improvement and New Emergency Response Act (?2006 MINER Act?), Pub. L. No. 109-236, 120 Stat. 493 (2006) was enacted in a bi-partisan move to strengthen the 1977 Mine Safety and Health Act. This action followed several underground coal mining accidents at the Sago and Aracoma Mines in West Virginia and the Darby Mine in Kentucky. The focus of that legislation was, in part, to force technological development and implementation. It involved the recomposition and training of rescue teams. Requirements for sealing worked out areas of mines were changed when MSHA invoked its Emergency Temporary Standard (?ETS?) authority for the first time in many years. Increased penalty amounts were established for certain types of violations for all types of mining, and minimums were set for unwarrantable failure violations issued under Section 104 (d)(1) and (d)(2); 30 U.S.C. Section 814 (d)(1),(2). The entire 30 C.F.R. Part 100 penalty criteria was revamped in a rulemaking, effective in April 2007. The visions were ambitious and noteworthy and those in industry and government have spent the last four years working through the aftermath of intended and unintended consequences of these changes. The penalty structure arrived at in 2007 has proven unwieldy and has contributed to the increase in contested caseload now before the Federal Mine Safety and Health Review Commission. In essence, litigation under the Mine Act ground to a virtual halt when the number of cases increased but the budget for Administrative Law Judges, who hear the cases, and the Solicitor?s office who represents MSHA, was not increased. Addressing the backlog effectively was one of the major challenges when Joe Main was confirmed as Assistant Secretary in early 2010.

Jan 1, 2011

By P. Schmieder

"The close vicinity of mining companies to other sites that are used for commercial and residential purposes or to areas under conservation as well as the fact that the people become more and more sensitive to emissions have led to a negative attitude towards mining operations in the neighborhood. It is above all the use of drilling and blasting techniques that give rise to objections, in the course of which demands for more environmentally-friendly production methods have been voiced. It is in this context that production methods without the use of explosives are considered as an option. After all, the use of such production methods is the only alternative for some quarry operators. The question is what are the true benefits of these techniques and what is the relation between a possible improvement of the environmental effects on the one hand and the technological potential as well as the costs on the other. It is intended to assess the mining techniques for solid rock in their entirety. This paper will therefore look at the aspects for assessing mining techniques in the context of their environmental impact and the costs."

Jan 1, 2005

By M. Heger

February 2, 1999 marks a milestone in earth-moving technology at the San Miguel Lignite Mine. It was on that date that The North American Coal Corporation (NAC) took delivery of three Leica Dozer 2000 GPS grade control systems for use on its bulldozers. The primary reason for the purchase of these grade control systems was to prove that GPS technology could safely and economically be utilized on heavy equipment to assist operators in defining grades. If these properties were successfully demonstrated, the ultimate vision of the project was to expand the system to a point were GPS would become the primary means of providing grade control information to the mine’s heavy equipment operators. Twenty nine months and more than $500,000 later this vision was realized when the final bulldozer operating at the San Miguel Lignite Mine was equipped with Dozer 2000. Presently North American Coal has a total of nine Dozer 2000 GPS grade control systems at San Miguel providing cut and fill information to operators 24 hours a day. These grade control systems have allowed the San Miguel operation to increase safety, reduce costs, improve operator attitude, and better ensure environmental compliance. This article discusses both the nature of these benefits and some of the issues that had to be dealt with along the way.

Jan 1, 2002

By D. F. Machuca-Mory

A change of support model consists of a procedure to change a stationary histogram at a small data scale to represent a larger scale; typically a distribution of sample drill-hole data is changed to represent a chosen selective mining unit (SMU) scale. Most grade variables average arithmetically. Thus, the mean stays the same for different scales, and the variance changes according to well-established theory using average variogram values. The longstanding challenge has been to predict how the shape of the histogram changes. The discrete gaussian model is widely used because it appears reasonable and introduces few artifacts; there are no artificial minimum/maximum values and the target mean and variance are reproduced exactly. The resulting distribution shape, however, is strongly dependent on a multivariate gaussian distribution. The authors generalize the approach by taking advantage of a property of the isofactorial model, which allows one to specify where the random function falls on the spectrum between a low-entropy mosaic model and a maximum-entropy diffusion model. A measure of dissemination (MD) is computed using a ratio of the madogram and the variogram. The change of support algorithm is developed that uses a variable measure of dissemination (VMD) that is easily calculated and fit to data from the deposit. The resulting VMD change of support model is very flexible to represent different mineralization styles encountered in practice; global predictions of recoverable reserves are more accurate and decision-making is improved. A number of real examples are shown to demonstrate the approach.

Jan 1, 2008