Search Documents

By M. A. Oskouei

Draglines are the main energy consumers in strip mines. Given the growing cost of energy and environmental concerns, it is important to properly understand dragline energy efficiency. The goal of current research at Missouri University of Science & Technology is to account for operator practice and operating conditions in modeling dragline energy efficiency. This paper presents preliminary correlation analysis and a framework for stochastic modeling of dragline energy efficiency. Thirteen operating parameters (including cycle times, payload, swing angle, and height of dump pile), operator working schedules, operating conditions, and drag, hoist, and swing energies were monitored for an 85 yd3 dragline. Operator effects were examined by two-sample t-tests. The relation between the parameters and energy consumption were assessed by correlation analysis and a stochastic modeling framework has been proposed for dragline energy efficiency. The results show that operator effects are significant (p< 0.05) and energy efficiency is correlated with operating parameters. The completed model will help the coal mines better predict energy consumption, with uncertainty, for different operating conditions.

Feb 27, 2013

By Dennis P. Martin, Michael M. Fitz, James E. Friant

Methods for reducing the cyclic nature of drill and blast tunneling operations have been long needed. A miniature blasting system using 10 mm (.375 in.) holes, 0.91 m (36 in.) deep, and blasting only one hole at a time makes it practical for men to work behind a shield, remaining at the face during the entire process. A prototype automated module was developed to drill, load the hole and initiate the detonation without moving from the hole. A unique cost effective gell explosive and a novel, low cost initiation method were developed.

Jan 1, 1989

By A. J. Kwitowski

Remote control is usually associated with deep mine, continuous mining machines. This is because thin-seam operation precludes an onboard operator&apos;s compartment or the mine has approval to conduct extended cut mining. Using a tethered or radio-linked control box, the remote operator is typically situated 3 to 15 m (10 to 50 ft) from the working face. The operator receives direct operational cues through senses like vision, hearing and feel. Remote control is sometimes touted as a safety feature. However, this is not always true, as operators are not provided protection from roof and rib falls or being crushed between the machine and a rib. Remote control operators are also left exposed to dust and noise. Teleoperation described here is the computer-based, distant control of mining machinery from a protected operator compartment located out of the line-of-sight from the operational site. Video, sound and other sensory information are gathered through sensors and electronically transmitted to and displayed at the operator&apos;s location. The teleoperator responds to the information and makes decisions that are initiated by control devices (usually switches). These control commands are then electronically transmitted to the re¬mote machinery and the appropriate machine function(s) are carried out. Teleoperation increases the safety of mining machine operators as it removes them from the immediate vicinity of hazards. The US Bureau of Mines&apos; involvement with teleoperation dates back to 1979. Following feasibility studies, a highwall milling system (HMS) was developed and tested. A deep, thin-seam, room-and-pillar system (TSRPS) has been designed and is currently being surface tested.

Jan 1, 1992

By Peter Campi, Harry R. Asche, Ian P. Callow, Edmund G. Taylor, P. Scott Smith

The US$1,850 million EastLink project is a 39km tollway and includes twin 3-lane,1.5km long, undrained driven tunnels. The hard rock tunnels are being built to avoid passing the motorway through the Mullum Mullum Valley and so to help preserve the unique flora and fauna in the area. This paper describes several of the key issues in the tunnel design and construction, including: the integration of the temporary support design with the Contractor’s tunnel excavation and support procedures, including sharing of responsibility between the Designer and Contractor for support type selection and the production of a project specific rock mass classification system to enable more objective determination of ground conditions. detailed hydrogeological assessments during the design and construction phases to allow confirmation of design loads for the tunnel lining design and the various suite of waterproofing tools in order to meet the project inflow requirements. development of a pre-cast invert solution to the main tunnel secondary lining to enable faster lining construction and to minimize risks to the tunnel membrane associated with fixing reinforcement and construction traffic.

Jan 1, 2007

By William R. Yernberg

The combined 76th Annual Minnesota Section of SME meeting and 64th Annual University of Minnesota Mining Symposium were held April 8and 9, 2003, in Duluth, MN. This year’s theme was “Stakeholders, Partners in Change.” The meeting included four keynote speakers, technical presentations and a tradeshow. Engineers, executives, mining managers and suppliers from throughout the United States and eastern Canada attended the meeting. Reflecting the theme of the meeting, all agreed that the mine owners, the government, the community and the employees are all “stakeholders.” They must be “partners in change” for the iron ore mining industry to survive in the region. Compared with past meetings, where improved technology was the primary focus, this year the focus was on the dramatic restructuring of the entire industry. As noted by several of the speakers, “This time, the change is not in technology.”

Jan 1, 2003

The Canadian mining industry is one of the strongest in the world. Not only does the country produce a sizable amount of minerals and metals, Canada plays host to hundreds of global mining companies, large and small. The country, for the most part, recognizes the importance of natural resource development, particularly mining, to its economic well being. Like any country, though, there are federal and provincial regulations on the books that the industry takes issue with. But there are also certain economic incentive programs in place to encourage exploration and mine investment. And, unlike the industry and the United States government, the Canadian government and mining industry appear to have a reasonable working relationship.

Jan 4, 2010

The Awareness and Preparedness for Emergencies at the Local Level (APELL) program is a process that helps people prevent, prepare for and respond appropriately to accidents and emergencies. APELL was developed by the United Nations Environment Program, in cooperation with industry groups, governments and local communities. Since its beginnings in1988, the program has been implemented in more than30 countries. APELL is a tool for bringing people together to allow effective communication about risks and emergency response. The program provides a common-sense approach to accident prevention and response.

Jan 1, 2003

By M. Rice, M. Stanley, J. Marlow

Arizona construction aggregate industry remains in the crosshairs of public debate, caught between the need for aggregate-based building materials and alternative, high-value land-uses. To better manage lands and improve land-use decisions, the Arizona State Land Department has need for a system to assess potential aggregate resources on State Trust lands, and assign dollar values accordingly. Thereafter aggregate values can be compared to residential, commercial, agricultural, recreational, and habitat values -- in a determination of highest and best land-use.

Jan 1, 2002

By S. B. Bealko

In response to recent mining disasters and new mine rescue team legislation, NIOSH researchers conducted meetings across the United States with mine emergency response experts to investigate current needs and issues. Some of the issues include emergency response preparedness, mine rescue contests, real-life training capabilities, and training facilities. Many new teams are being formed that must be trained for mine rescue team competitions as well as be ready to respond to a variety of mine emergencies including a fire or explosion, a massive roof collapse, mine inundations, or vertical shaft rescue situations. Therefore, it is important that these teams are adequately prepared and trained. This paper presents a summary of domestic and international coal mine rescue training facilities and identifies those that provide unique, real-life, and/or state-of-the-art training. Research findings from this report will be used in further NIOSH investigations to improve coal mine rescue training. DISCLAIMER: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2009

By H. A. Oliveira, A. Azevedo

Physical and chemical characterization and solid/liquid separation of turbid waters from a river affected by an iron tailing rupture disaster (Gualaxo do Norte River, Brazil) were studied at bench scale. Parameters such as turbidity, pH, surface tension, electrical conductivity, total suspended solids (TSS), particle size distribution (micro- and nanoparticles), and zeta potential were analyzed from samples collected at three different river depths. The results in all samples showed the presence of micro- and nanoparticles, ranging in diameters from 100 nm to 200 μm. Best results for flocculation and settling were obtained at pH 7.5, through an innovative combination of eco-friendly reagents: (i) ferric hydroxide precipitates (10 mg L−1 Fe3+) to sweep (enmesh) the dispersed solids and (ii) gelatinized starch (5 mg L−1 ) to form large flocs. The results showed removals between 90 and 100% of total suspended solids (micro- and nanoparticles), resulting in clear water with residual turbidity < 7 NTU. It is believed that this innovative alternative has a high potential for flocculating and treating the turbid water at Gualaxo do Norte River, assisting the water treatment stations.

By Taehong Kim, Carl Pannuti, Nikolas Sokol, Walter Herrick

BACKGROUND This paper discusses work performed as part the rehabilitation of the gravity flow section of the New Croton Aqueduct (NCA) during an approximately two year period between 2004 and 2006. The goal of the project was to restore the gravity flow section of the NCA to optimal operating condition, extending the lifespan of this significant water supply for the New York City metropolitan area. Rehabilitation of the NCA was purposely scheduled before the completion of the new NCA Water Treatment Plant now under construction (Figure 1). The NCA is a 3.73 to 4.34 m (12.25 to 14.25 ft) diameter brick-lined circular andhorseshoe shaped water tunnel constructed between 1885 and 1891. The NCA conveys water for approximately 50 km (31 miles) by gravity and pressurized flow from the New Croton Reservoir in Westchester County, NY to distribution and reservoir points along its alignment, terminating at a distribution station at 135th Street and Convent Avenue in Manhattan, NY. Prominent features of the NCA include a large intake facility at New Croton Reservoir, 38.6 km (24 miles) of gravity flow horseshoe shaped aqueduct, 11.3 km (7 miles) of pressurized flow circular aqueduct, 2 siphons, and 36 open shafts and headhouse chambers which are used as sampling, access and blow-off locations. Until a partial inspection in 1982, the NCA had flowed continuously since its completion nearly 100 years prior. Flow tests have confirmed that the NCA can convey up to 12.7 m3/s (290 mgd) (Figure 2). Cover depths of NCA vary considerably, ranging from a few to hundreds of meters, typically of hard rock. Primarily mined using means conventional for the late1800s, construction of the NCA also employed cut and cover methods in several low-lying sections of the alignment, totaling approximately 1.6 km (1 mile). The NCA crosses through numerous lithologic changes, fault/shear zones and under several significant water bodies including the Pocantico, Saw Mill and Harlem Rivers and the Tarrytown Reservoir. The NCA passes under the Harlem River as a siphon at a depth of approximately 122 m (400 ft) below grade (Figure 3). Soon after construction the Aqueduct Commission Reports on the New Croton Aqueduct documented prominent defects such as large voids behind the lining. More recently, large-scale inspections of the gravity flow section performed during the 1990sand a 2004 inspection of portions of the pressurized sections of the NCA have revealed additional defects such as open and/or deteriorated masonry joints/cracks, leaks ranging from trickles to several liters per minute into and out of the NCA, missing bricks, formed openings, and in one place, a rupture through the liner with discernable

Jan 1, 2007

By W. Rogers

Blast-induced rock mass displacement can have a significant impact on ore loss & dilution. The mischaracterisation of the grade boundaries both prior to, as well as a result of blasting can lead to significant financial losses on account of ore loss and dilution. Ore dilution occurs when waste material is miscategorised as ore and sent for processing or stockpiling, diluting the run of mine head grade and recovery. Ore loss takes place when valuable mineral is miscategorised as waste and sent to the waste dumps, thus never being processed and recovered. Extensive research has been conducted at the University of Queensland over the last fifteen years to understand the impact of blast movement on ore loss and dilution. Recent outcomes of this research have developed innovative tools and techniques to measure and model blast movement. These techniques have been implemented at Ahafo gold mine in Ghana to understand blast movement dynamics and to implement solutions to reduce blast-induced ore loss and dilution. These solutions are validated through controlled trials and have been incorporated into site standard operating procedures to sustain the benefits.

Jan 1, 2012

By David Newman

Multiple seam underground coal mining is ubiquitous in Appalachia. Many coal properties have from two to ten or more economically mineable coal seams. Because of the ability to penetrate 600-feet to 1,000-feet or deeper into the mountainside leaving panels of web pillars separated by barrier pillars, highwall mining is a hybrid between surface and underground mining. As a result, many of the ground control problems commonly associated with multiple seam underground mining exist with multiple seam highwall mining. These include: i) multiple seam interaction between web and barrier pillars in superjacent mines, ii) subsidence and caving propagating to overlying seams and mines, iii) pooled water and the potential for inundation resulting from a breakthrough between an active highwall mine and abandoned underground mines in the same or superjacent seams, iv) the presence of overlying or underlying mine workings where pillar columnization in the active mine is not possible, and v) the question of whether to mine ?top-down? or ?bottom-up.? Case histories are presented from southeast Ohio where the Middle Kittanning No. 6 and Lower Kittanning No. 5 seams are successfully highwall mined with 20-feet to 40-feet of largely shale interburden. A highwall miner was caught in a highwall collapse in the Middle Kittanning No. 6 seam when it was overmining auger workings in the Lower Kittanning No. 5 seam. Multiple seam interaction caused by the overmining transferred overburden stress onto the Lower Kittanning No. 5 seam. The overburden concentrated through web pillars initiated auger web pillar failure, resulting in roof collapse and subsidence in the Lower Kittanning No. 5 seam that propagated up to the Middle Kittanning No. 6 seam. A second case history involves multiple seam highwall mining in southeast Kentucky. The A3 Rider, A3, B2, and C1 seams are being highwall mined around abandoned underground mines in the A3 and B2 seams and augering in the A3 Rider. Because of spoil storage constraints for the surface contour mines, the highwall miner follows the active pits in each seam so a standard sequence of ?top-down? or ?bottom-up mining does not exist.

Jan 1, 2009

By R. Schipper

Two bench scale biochemical reactors (BCRs) were operated over a period of 3 months for the removal of uranium, radium, and selenium from mining influenced water (MIW). A BCR is an anaerobic reactor comprised of organic and inorganic substrate including woodchips, straw, sawdust, and limestone. Uranium and selenium are removed in a BCR by biological reduction of oxidized species (i.e., selenite, selenate) to less soluble forms (Pahler et al. 2007, Blumenstein et al. 2008, Rutkowski et al. 2013). It is believed that radium may be removed through absorption to the biomass in the BCR. The bench scale BCRs were constructed of 6 inch PVC columns with a top to bottom flow configuration. The bench influent water consisted of three different water ratios from two adit seeps. BCR hydraulic retention times of 24 to 36 hours were targeted during the study. Influent concentrations ranged from 19 ug/L to 1.86 mg/L for dissolved uranium, 12 ug/L to 270 ug/L for dissolved selenium, and 4.9 pCi/L to 24 pCi/L for radium 226. The average and maximum dissolved uranium removal was 93.6% and 98.5% respectively, the average and maximum dissolved selenium removal was 93.3% and 98.9% respectively, and the average and maximum radium 226 removal was 89.5% and 100% respectively.

Feb 23, 2014

By Gregory Yates

INTRODUCTION Project Description The Silver Line is a Bus Rapid Transit (BRT) Line and is Boston?s newest transit service. Silver Line Phase I extends along Washington Street entirely on the surface in priority bus lanes from Dudley Station in Roxbury through the South End and Chinatown neighborhoods to downtown Boston. The Phase I opened in July 2002. Silver Line Phase II consists of an underground transit tunnel from South Station to the South Boston Waterfront with underground stations at Courthouse and World Trade Center to Silver Line Way east of D Street. Phase II continues through the Ted Williams Tunnel to all the terminals at Logan Airport, and on the surface to the Boston Marine Industrial Park and City Point. Phase II opened in December 2004. Silver Line Phase III is a one mile tunnel connection to the existing Phase II tunnel in the vicinity of South Station and will eventually portal on Tremont Street just north of Marginal Road. After leaving the portal, the buses will use dedicated bus only lanes on the surface roadway network to connect to the Phase I service. Figure 1 shows the alignment of the Silver Line upon completion of the Phase III project.

By Ryan C. Stephan, Christopher Mark

"Some of the weakest roof in United States coal mines is found in the Illinois Basin. Historically, the Illinois Basin has also suffered from high rates of unplanned roof falls and rock fall injuries. During the past decade, however, roof fall and rock fall injury rates have fallen dramatically, and are now lower than the national average. Several technologies are responsible for the improvement. Roof screen was rarely used ten years ago, but a number of mines now use it on a regular basis to prevent rock falls and rock fall injuries. Other roof skin control fixtures and work practices have contributed as well.The reduction in roof falls is also directly attributed to enhanced intrinsic roof support. Stiffer primary bolting patterns have reduced the magnitude of roof spalling and roof sag. They have also helped create a more intact beam that is able to be suspended from longer cable bolts. Cable bolt design methodology has also contributed to this reduction in roof falls. Some early cable bolt applications were unsuccessful because they employed as few as two cable bolts per intersection. This paper describes a methodology for estimating rock loads for support design.ROOF FALL TRENDS IN THE ILLINOIS BASINAlthough the Illinois Basin has a long history of poor roof conditions and high rates of unplanned roof falls and rock fall injuries, recent data indicates a change in the trend. Roof fall rates are determined by dividing the total number of non-injury roof falls by the total number of hours worked underground. The data is considered for 200,000-man hours. While the Illinois Basin was once a coalfield experiencing roof falls at nearly twice the national average, it is now at or below the national rate. Figure 1 indicates the trend over the past 20 years. In 2008, the Illinois Basin mines experienced 5.06 roof falls every 200,000-man-hours, compared to only 0.75 in 2018.There has also been a significant reduction in the rate of rock fall injuries in the Illinois Basin coal mines, as shown in Figure 2. In 2008 there were 1.48 rock fall injuries every 200,000-man-hours, compared to only 0.43 in 2018.ILLINOIS BASIN COAL ROOF GEOLOGYThe roof rock in the Illinois Basin has been studied in the past to understand the primary causes of roof failures (Molinda et al., 2008; Thompson, 2010; Molinda and Mark, 2010). Rusnak and Mark (2000) evaluated 10,000 laboratory strength tests from 800 rock units and concluded that for shale, siltstone, and sandstone, the strength of the Illinois Basin variety was less than half that of the same rock types in Central Appalachia (Figure 3). A study of Coal Mine Roof Rating (CMRR) measurements in more than 200 US coal mines also found that weak roof was predominant in the Illinois Basin (Mark and Molinda, 2005)."

Jan 1, 2019

By F. Khorram

Image processing is a technique that simulates the human vision system. This technique enables applying every statistical or intelligent operation to recognize differences. In this way this new technique is used in quality control systems in most industries. Studying sedimentary rocks is very important from the economic point of view. Some units of sedimentary sequences involve different mineral deposits, hydrocarbon and water resources. Therefore it is important to identify and classify different sedimentary rocks. Descriptive classification of sedimentary rocks is usually based on visual and textural features and chemical composition of a sample. In this paper different samples of a limestone mine in central part of Iran are classified. The samples were collected from different parts of the mine and crushed down in size from 2.58 cm to 3.58 cm. The rock samples were labeled based on percentage of chemical and lithological compositions. Each sample was assigned to one of the distinguished groups. The images of the samples were taken in appropriate environment and processed. A total of 74 features were extracted from the identified rock samples in all images. In order to feature dimensional decrease, principal component analysis method was used. Then Bayesian statistical algorithm was used as a useful tool for classification. Classification Correctness Rate (CCR), calculated for the test data sets are %88, %68, %61 and %72 for the first to fourth class respectively. Therefore it can be inferred that the extracted features of images are appropriate indicators for different samples identification. These precise results besides the advantages of image processing technique, which are increasing speed of operation and decreasing cost, appears to be a desirable success.

Jan 1, 2012

By Felix E. Mutschler

Alkaline rock-related precious metal deposits include: • orthomagmatic platinum group elements (PGE) ± gold (Au); • porphyry copper-silver-gold (Cu-Ag-Au, ±PGE); • epithermal Au-only, and Au-Ag-base metals; • submarine exhalative Kuroko-, Cyprus-, seamount- and Yellowjacket-type deposits; and • enigmatic deposits akin to Olympic Dam. Coeval epithermal deposits related to porphyry deposits suggest the two types represent separate immiscible fluids evolved in oxidized, CO2-rich alkaline magma chambers. Alkaline rock provinces develop above mantle hot-spots, but crustal structures control the final distribution of magmas and ore fluids. Prospecting guides for alkaline rock-related precious metal deposits include the presence of evolved alkaline rocks, pervasive K-metasomatic, redox and carbonatic alteration and low level Au (±Te, etc.) anomalies. Although alkaline igneous rocks crop out in less than 1 % of the area of the North American Cordillera and craton, alkaline rock-related ore deposits have produced nearly 13% of the total United States and Canadian lode gold production. Large (31-t or 1 million-oz) deposits are common (Fig. 1), and additional deposits and reserves are being discovered. New genetic models are evolving, making alkaline rock-related precious metal prospects attractive exploration targets.

Jan 1, 1991

By J. Torma-Krajewski, M. Lehman

In 2005, NIOSH and Badger Mining Corporation entered a partnership to implement ergonomic interventions, including a systematic process, to address exposures to risk factors that may result in musculoskeletal disorders or other types of injuries/illnesses. As a result of this partnership, an ergonomics process was integrated with the existing safety and health program to promote an on-going application of ergonomic principles, and over 40 task-specific interventions were implemented during the first year of the process. This paper presents details of the process integration, and several examples of task-specific interventions that reduced exposures to risk factors.

Jan 1, 2007

By J. Hanna, I. Anazia

Selective fatty acid flotation of carbonate gangue from sedimentary apatites was achieved under acidic pHs without a specific apatite depressant and without conditioning the pulp with the collector. Concentrates (35% to 38% P2O5, 0.8% to 1% MgO) with high recoveries (80% to 85%) were produced from Indian and Chinese dolomitic ores. The calcareous and/or dolomitic-siliceous phosphate ores of South Florida and Utah required two flotation stages: one for carbonate removal, as mentioned above, and the other for phosphate recovery from siliceous gangue. Preliminary tests on the South Florida ore gave concentrates analyzing 29% P2O5 and 0.8% MgO, with a P2O5 recovery of 76%. A concentrate obtained from the western US phosphate ore from Utah assayed 30% P2O5 and about 1% MgO, with a P2O5 recovery of 89%.

Jan 1, 1988