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By Jacob Carr, Chenming Zhou, Nicholas Damiano, James Noll, Jingcheng Li

Machine-related injuries are one of the major safety concerns in underground coal mines. Severe injuries and fatalities occur when a miner is struck, crushed, or pinned by mining equipment such as a continuous mining machine (CMM), shuttle car, or a scoop. Proximity detection systems (PDSs) have been applied in mining to reduce these types of injuries and fatalities. All of the PDSs that are currently approved by the Mine Safety and Health Administration (MSHA) for use in underground coal mines are magnetic-field based and could be affected by metallic objects such as trailing cables. Researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated the influence of trailing cables on the performance of PDSs. In particular, the magnetic field coupled from proximity system generators to a de-energized trailing cable was characterized. The results show that significant energy can be coupled from the proximity system generators to a trailing cable when there is a closed loop in the cable. The effect on PDS performance from the magnetic field radiated around an energized trailing cable was also quantified for different current amplitudes in the cable. It is shown that the magnetic field caused by the electric current in the trailing cable mainly consists of a 60-Hz signal and its harmonics which causes little interference to the PDS. The results presented in this paper can help PDS manufacturers to design better systems that are more immune to these effects.

By S. A. Osterberg, J. L. Breckenridge, R. S. Popielak

Multidisciplinary investigations were completed to prove the availability of water resources for the proposed San Cristóbal silver-lead-zinc mine in the arid Altiplano of Bolivia. Surface water resources are scarce, of poor quality, and unsuitable for development. Therefore, hydrogeological reconnaissance targeted alluvial aquifers for development. Follow-up resistivity, refraction, and water quality assessments were used to prioritize areas with prolific production potential. Pumping tests and regional water balance analysis indicate an alluvial aquifer can sustain the required approximately 40 000 m3 per day production for the life of the mine and predict no significant negative environmental effects on local groundwater users and the environment.

Jan 1, 2002

By Chen Lin

Tectonic stress is an important parameter for understanding the dynamics of underground engineering and for the exploitation of coalbed methane. Multiple-period structural features usually have complex spatial relationships in tectonic superposition areas, which provides evidence for identification of the sequence of the tectonic stress period. Conjugated joints and slickensides are used to reconstruct the tectonic stress of the No. 8 Mine in Pingdingshan. Based on the geological unit division and field measurements, data on hundreds of joints and slickensides are collected from 33 stations. The tectonic stress results indicated by the conjugated joints show that there are mainly four directions of tectonic stress: NEE-SWW, NW-SE, NE-SW, and NNESSW. The tectonic stress results of the slickensides indicate that there are mainly four directions of tectonic stress: NNE-SSW, NNW-SSE, NEE-SWW, and NW-SE. According to the systematic analysis of the joints and slickensides, this paper separates the superposed joint and slickenside sets and identifies the tectonic stress periods with their abutting relationships. Three tectonic stress periods are determined and the sequence of the tectonic stress periods is NE-SW, NW-SE, and NEE-SWW. The results are consistent with other tectonic stress measurements for both the region and the locality.

By Chen Lin

Tectonic stress is an important parameter for understanding the dynamics of underground engineering and for the exploitation of coalbed methane. Multiple-period structural features usually have complex spatial relationships in tectonic superposition areas, which provides evidence for identification of the sequence of the tectonic stress period. Conjugated joints and slickensides are used to reconstruct the tectonic stress of the No. 8 Mine in Pingdingshan. Based on the geological unit division and field measurements, data on hundreds of joints and slickensides are collected from 33 stations. The tectonic stress results indicated by the conjugated joints show that there are mainly four directions of tectonic stress: NEE-SWW, NW-SE, NE-SW, and NNESSW. The tectonic stress results of the slickensides indicate that there are mainly four directions of tectonic stress: NNE-SSW, NNW-SSE, NEE-SWW, and NW-SE. According to the systematic analysis of the joints and slickensides, this paper separates the superposed joint and slickenside sets and identifies the tectonic stress periods with their abutting relationships. Three tectonic stress periods are determined and the sequence of the tectonic stress periods is NE-SW, NW-SE, and NEE-SWW. The results are consistent with other tectonic stress measurements for both the region and the locality.

By S. Christiansen, G. R. Winslow, R. W. Kobler

Todays End of Life vehicles are shredded and their metal components recovered and recycled by standard methods. The remaining non-metallic fraction is shredder residue, and contains vast amounts of high value engineering plastics. None are today recovered. Discussed are the developmental approaches used in the first process to recover these valuable plastics. Examined are initial laboratory studies, pilot plant design and construction, product development, results, and flowchart explanations.

Jan 1, 2001

By Jennifer B. Leinart

Sixty percent of the mines responding to the sixth annual Mining Cost Service labor survey reported increases in wages averaging 3.4% over the preceding 12 months. Only one mine reported a decrease in wages and this was accompanied by initiation of a substantial profit-sharing plan. Thirty-nine percent reported no change in wages. Thirty-seven percent reported using some form of incentive bonus plan. Mining Cost Service annually surveys coal, metal, and industrial mineral mines throughout the United States. Information about wages, benefits, and incentive bonus plans is part of an extensive data collection program to monitor cost areas of significance to the mining industry. This year, 131 mines responded to the survey. The data is collected by sending questionnaires to personnel managers at active mining operations. The information included in this article was taken from the returned forms, from labor contracts provided by some of the mines, and from followup telephone calls. This year's data was collected between November 1988 and February 1989.

Jan 1, 1990

More than 410,000 visitors from 171 countries helped bauma ’04 set new attendance records at the world’s largest construction machinery and mining technology show. The show, held in Munich, Germany March 29-April 4, marked bauma’s 50th anniversary. At the last bauma show in 2001, attendance was about 406,000 people from 157 countries. At bauma ’04, international attendance increased to 31 percent from 27 percent in 2001. In addition to record-setting attendance, bauma ’04also attracted 2,801 exhibitors, up from 2,341 in 2001. Exhibitors came from the United States, Europe, China, Japan and the Middle East. Exhibitor space topped 500,000m2 (5.4 million sq ft), another record. And, for the first time, there were more foreign exhibitors than German exhibitors, show organizers said.

Jan 1, 2004

By K. V. Raj, C. A. Berry, A. T. Weakley, A. L. Miller, P. R. Griffiths, D. A. Parks

Diesel particulate matter (DPM) has been classified as a carcinogen to humans by the International Agency for Research on Cancer. As a result of its potential carcinogenic nature, DPM exposure is regulated by the Mine Safety and Health Administration. Currently, diesel emissions in the workplace are monitored by collecting the aerosol onto filters, which are then sent to a laboratory for thermal-optical analysis using the NIOSH method 5040. This process can take days or even weeks, and workers can potentially be exposed to excessive levels of DPM before the problem is identified. Moreover, the delay involved in getting the loaded filter to the lab inevitably means the loss of some of the more volatile organic carbon. To remedy this delay, researchers from the National Institute for Occupational Safety and Health are seeking to develop a field-portable, real-time method for measuring elemental and organic carbons in DPM aerosols. In the current study, the use of mid-infrared spectrometry was investigated. It is believed that mid-infrared spectroscopy is more suitable for use in a real-time field-portable device than thermo-optical analysis methods. This article presents a method for measuring organic carbon (OC) and elemental carbon (EC) in DPM for a broad range of OC/EC ratios. The method has been successfully applied to laboratory-generated and mine samples.

By M. K. McCarter

The history of mining education, like the history of the mining industry, is typified by “boom and bust” cycles. In academia, the perpetual problem can be stated as “too many graduates for the jobs or too many jobs for the graduates.” The deep “bust cycle” that spanned the 1990s through 2003 spawned renewed efforts to eliminate, consolidate, restructure, rename, reinvent or otherwise change mining education to make it (for some) more fiscally or socially acceptable. During this period, a number of mining programs were eliminated, and by the late 1990s senior people in academia and their counter-parts in industry became increasing concerned about the very real possibility that strategic disciplines may disappear altogether. As a result, the Mining and Metallurgy Society of America (MMSA) created an educational committee to explore how industry could help preserve key programs necessary to provide future professionals. Several meetings were held to assess the problems and look for solutions. In 2004, this effort culminated in the first of the “Engineering Education” sessions to be held at the SME Annual Meetings. In response to the information presented in this first meeting, Marc LeVier (then president of MMSA) invited a number of the participants to reconvene the following day. An action plan was formulated and a task force was organized. To more fully represent all industry sectors, SME later that year assumed the sponsorship role for the task force.

Jan 1, 2007

By T. W. Peglas, J. Doherty, R. A. Day

The South East Transit Project is a $520 million project in Brisbane, Australia which includes the construction of a 32 km Busway to access the south-eastern suburbs. Close to the centre of Brisbane, tunneling techniques have been used to minimise surface disruption. This paper describes some of the features of the longest driven tunnel on the project, the Vulture Street Tunnel. The Busway is a two lane expressway for buses which requires a 10.2 m finished width and a 12.6 m excavated span of driven tunnel. The Vulture Street Tunnel carries the Busway at minimal cover beneath the operating Vulture Street Railway Station, beneath a three storey office building and beneath the roadway to the Mater Hill Busway station. Halfway along the route, a Y-junction has been constructed to enable future connection with a light rail route. Key features in the design and construction of the Vulture Street Tunnel include: Use of canopy tubes to drive a 12 m wide tunnel beneath operating railway tracks with less than two metres of cover in highly weathered rock. Underpinning the office building in the route of the tunnel construction from within the building carpark. Construction of a 24 m span Y-junction with 7 metres cover of weathered and faulted rock. Use of predictive analysis as an adjunct to traditional back analysis to estimate the tunnel settlements from pressuremeter test results. This paper describes the design methodology with particular reference to settlement prediction, as well as construction innovations used to complete the tunnel. This paper will be of interest to all designers who have to create large spans in minimal cover in weak rock in urban areas and who have to predict the settlement

Jan 1, 2001

By R. Schulz, K. King

Concentrating Line 6 just went down again. The control room operator checks the graphic display. Only one piece of equipment shows an alarm. Clicking on the ball mill icon, he discovers the culprit was the low flow lube switch. The flow looks okay now, but it is the third time this week the switch has stopped the line. Maintenance is called, the switch replaced and the line is up running again. Sending the right person to the right spot immediately can save hundreds of hours of downtime every year. This paper discusses the principles behind implementing smart First-Out Fault Detection to dramatically reduce equipment downtime in new, or existing control system architectures. Methodologies are presented to maximize the system benefits, while minimizing development costs. Case histories are presented for a number of successful implementations in mineral processing plants.

Jan 1, 2001

By David Smith, Bernie Martin

The Queens Bored Tunnels consist of 11,000 feet of 19'-6" inside diameter tunnels mined through rock, mixed face and dense glacial till, constructed with bolted gasketed one pass reinforced concrete liner. The tunnels are to be excavated with a pressurized face TBM, either EPB or slurry. The construction of the tunnels will require ground stabilization in the mixed face area, instrumentation and monitoring of railway infrastructure, underpinning of bridges, relocation and protection of utilities, demolition of some industrial buildings, construction of open-cut approach tunnels and emergency exits and vent plants. The purpose of this paper is to describe the scope of work, the suggested methodology and the proposed construction schedule.

Jan 1, 2005

By William H. Langer

The annual consumption of sand and gravel aggregate in 2006 in the Phoenix, AZ metropolitan area was about 76 Mt (84 million st) (USGS, 2009), or about 18 t (20 st) per capita. Quaternary alluvial deposits in the modern stream channel of the Agua Fria River west of Phoenix are mined and processed to provide some of this aggregate to the greater Phoenix area. The Agua Fria drainage basin (Fig. 1) is characterized by rugged mountains with high elevations and steep stream gradients in the north, and by broad alluvial filled basins separated by elongated fault-block mountain ranges in the south. The Agua Fria River, the basin?s main drainage, flows south from Prescott, AZ and west of Phoenix to the Gila River. The Waddel Dam impounds Lake Pleasant and greatly limits the flow of the Agua Fria River south of the lake. The southern portion of the watershed, south of Lake Pleasant, opens out into a broad valley where the river flows through urban and agricultural lands to its confluence with the Gila River, a tributary of the Colorado River.

Jan 2, 2010

By Siegmund Babendererde, Jan O. Babendererde

Extruded Concrete Lining combines technological and financial advantages. The tunnel lining is reliably embedded in the surrounding ground as the fluid concrete is extruded at constant pressure directly behind the TBM supporting the exposed surface. Ground deformation from the TBM passage can be compensated and the ground will be pre-stressed by the extrusion process. Developments in concrete technology permit high speed tunneling by use of a slip formwork attached to the TBM. Realised projects in Milano (Italy), Lyon (France), Frankfurt (Germany) and Akima (Japan) will be demonstrated.

Jan 1, 2001

By Steve Kral

Despite low commodity prices and mining industry cutbacks throughout the world, Peru remains one of the industry’s bright spots. The country’s remarkable economic turnaround during the 1990s remains a model for other developing nations to follow. And the Peruvian government has not forgotten the industry that was instrumental in that turnaround. True, the country has not been spared the effects of the mining industry’s retrenchment that has occurred in other parts of the world. However, foreign mining companies remain committed to doing business in Peru. And the government remains committed to attracting foreign investment and maintaining a strong mining industry. This commitment was evident in September 1999during the 24th Convention of the Institutos de Ingenieros de Minas del Peru in Arequipa, Peru. More than 3,000 mining industry professionals from around the world attended the convention. And Extemin, the accompanying exhibit, featured more than 450 companies, many from the United States, Canada, Australia, South Africa and other countries.

Jan 1, 2000

By Joel Darmstadter

The position of the coal industry in America’s fuel and power picture remains one of prime importance. Measured in Btu terms, the industry is the country’s leading energy producer and an important exporter. Foreign coal sales yield annual proceeds of about $4 billion. Coal’s one-fifth share of the nation’s energy consumption is nearly as high as that of natural gas. Coal is the electric utility sector’s principal fuel supplier. It accounts for about55% of the electricity generated at power stations.

Jan 1, 1999

By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

In order to address the difficulty of accurate segmentation of froth images of different sizes, a method of froth image segmentation based on highlight correction and parameter adaptation is proposed. First, a machine vision system on a single-cell flotation machine is built to collect froth images. Homomorphic filtering is used to improve the uneven brightness and shadow of the images. Fuzzy c-means (FCM) clustering is then utilized to classify similar highlights that belong to the same froth. After Otsu threshold segmentation, a parameter-adaptive morphological operation is used to extract the marker points and edge bands and correct the froth edges in the original image. Finally, the modified image is filtered by morphological reconstruction, and the highlight mark is used as the local minimum point for watershed segmentation. Three sizes of froth images are segmented in comparative experiments. The results show that the proposed method is suitable for the segmentation of froth images of different sizes. The position of the extracted segmentation line is close to reality, with average over-segmentation and under-segmentation rates for froth images of 2.6% and 6.8%, respectively. The froth image segmentation performance is stronger than that of the other methods examined.

By E. F. Schnitzer, D. R. Haight, G. T. Krogman

The 1997 New Year’s Day Rogue River flood near Medford, Oregon, USA, entered historic channels, eroded a 150-foot-wide buffer, and captured an inactive gravel pond located within the channel migration zone. Channel redirection caused by pit captures threatened adjacent inactive gravel ponds. In response to this capture, a stakeholders group of concerned individuals and organizations was formed. This group ultimately developed a rehabilitation plan, which conformed to the Rogue River’s geomorphic trends. A two-dimensional model, FLO-2D, was used to evaluate channel splits, flood storage, backwater, and future conditions. Modeling results coupled with trend analysis were used to create a stable design where stream barbs, gravel redistribution, a channel outfall spillway, bendway weirs, bank reshaping, and revegetation were integrated into a single plan for a three-mile reach. The quick action by the stakeholders group averted further damage to the Rogue River system and surrounding environment. The project has preserved three miles of mainstem habitat, one mile of side channel habitat, and protected ten gravel ponds from pit capture.

Jan 1, 2006

By Franco Oboni, Iain G. Bruce

The design of tailings containment structures relies on well-understood engineering methods being applied consistently. Unfortunately, not all facilities are designed or managed to the same level of competency. To standardize procedures, the Mining Association of Canada (MAC, 1998) prepared a “Guide to Tailings Management.” It recommended review of designs and an assessment of the risks associated with tailings impoundments be implemented during all phases of amine life. This paper describes how the quantitative risk assessment (QRA) process can be used to define risks associated with the design, construction and operation of a tailings management facility. And it discusses how, once the risk tolerability curves (RTC) are defined for a project, they can assist the risk management (RM) process.

Jan 1, 2002

By Steve Kral

The domestic mining industry may be in the doldrums but there appears to be hope, at least from a regulatory standpoint. At least one US senator believes that the events of Sept. 11, 2001 made many citizens see the need for the country to become more self-reliant on its growing energy needs. Even before that tragic day, however, the Bush administration was making a strong push to open up more public land for energy and natural resource development.

Jan 1, 2002