Surface Coal Mining Operations Research Articles

Assessing the Rainfall Implications on Surface Coal Mining Operations: Thar Case Study

Rainfall directly impacts the open-pit surface mining operations in the Thar Coalfield, Pakistan. The overall lithology hosting the lignite type of coal seams in the study area includes Dune Sand, alluvium, and soft sedimentary rocks. Due to the presence of three primary aquifers, the strata overlying and underlying the coal seams are under substantial porewater pressure. Additionally, heavy rainfalls in the Thar area lead to the accumulation of water in mines and may cause pit flooding, making it impossible to continue mining activities until the water is pumped out. Pit flooding often results in equipment damage and production delays. The main focus of the study is to investigate the impacts of heavy rainfall on the mining activities at Thar Coalfield. Two major aspects of open pit mining are considered in this study, i.e., production, and dewatering systems. Due to heavy rainfall, a significant production deviation (V) was noticed in comparison to regular months. The quantity of water drained from the pit (Qa) and anticipated inflow quantity (Qt) values were compared for the rainy season and other times. It was observed that heavy rainfall increases the production deviation from the planned targets and also increases the pit dewatering cost. Moreover, this study suggests preventive measures to address potential losses arising from intense rainfall.

RISK MODELLING OF HEAVY MOBILE EQUIPMENT TO DETERMINE OPTIMUM REPLACEMENT AGES

Maintenance and physical asset managers often have to decide when a major asset needs to be replaced. The main objective of this study was to develop a methodology to determine the optimum replacement age of heavy mobile equipment that is close to the end of its life. The study was conducted on an old electric rope shovel used at a surface coal mining operation. The failure impact and failure probability estimates of components were obtained from subject matter experts through Delphi analyses. A stochastic-and-parametric-estimation modelling solution was developed to perform quantitative risk analyses using their inputs. The solution calculated the expected loss of the rope shovel as a function of machine-age within a 90 per cent confidence interval. The study demonstrated that the optimum replacement age of heavy mobile equipment can be obtained by modelling the expected losses due to the failure of critical end-of-life components, taking into account the uncertainty in data obtained from subject matter experts.

Examining the influence of settlement morphology and separation zones policies on the availability of shallow coal resources in the United Kingdom

In 2013, demand for coal in the UK was 60 million tonnes. Of this, 12.7 million tonnes (21%) came from indigenous sources; the majority of which was from surface mining (8.6 million tonnes). Many planning applications for surface mining of coal and the coal extraction that follows, are often a source of conflict with the communities who live within shallow coalfield areas. Policies which enforce a gap, or ‘separation zone’, between communities and surface coal mining operations exist in Wales and Scotland, but do not exist in England. This paper examines the effect of applying separation zones on the availability of shallow coal resources within two study areas; one within the South Wales Coalfield, the other within the Midlands Coalfield (comprising the Yorkshire, Nottinghamshire and North Derbyshire Coalfield areas). Density profiles and a shape-index algorithm are used to compare and contrast settlement morphology (i.e. shape or footprint) and distribution to determine whether they have a bearing on the areal extent of any potential separation zone applied. The implications on the availability of shallow coal resources of applying different separation zone distances around settlements within these two areas are explored. Results reveal that although the settlement morphology is important in determining the area of the separation zone, and has greatest influence in the South Wales Coalfield, the area of coal resource sterilised by the application of separation zones is greatest in the Midlands Coalfield due to it having a higher proportion of urban development situated on the surface extent of the shallow coal resource.

Processes of natural soil and vegetation recovery on a worked-out open pit coal mine (Bol’shezemel’skaya tundra)

The processes of soil and vegetation recovery after cessation of surface coal mining operations have been studied for the first time in the far north of Europe. Three stages of primary succession—from primitive algal groups to closed plant communities—have been identified, with the main role being played by soil algae at the zero stage, by herbs at the first stage, and by grasses at the second stage. A close relationship between the early stages in the development of phytocenoses and the stages of posttechnogenic soil formation is demonstrated.

Investigation of haul truck-related fatal accidents in surface mining using fault tree analysis

Trucks are the primary means of haulage in surface coal, metal, and nonmetal mining operations. The number of fatal accidents involving trucks is higher when compared to all other mining equipment. Mine Safety and Health Administration (MSHA) reports that 137 fatalities were haul truck-related in the United States between 1995 and 2011. A total of 12 accidents, including 13 fatalities, were recorded in surface coal mining operations in West Virginia (WV) during this period. The objective of this study was to better understand the root causes of accidents in WV. The Fault Tree Analysis (FTA) technique was used to systematically analyze these accidents. Results of the study indicate that inadequate or improper pre-operational check and poor maintenance of trucks were the two most common root causes of these accidents. A total of eight accidents occurred on haul roads, while 10 accidents occurred while the trucks were moving forward. The two most violated provisions of Code of Federal Regulations were 30 CFR§77.404 – Machinery and equipment; operation and maintenance (six times), and 30 CFR§77.1606 – Loading and haulage equipment; inspection and maintenance (five times).

Characterization of particulate matter (PM10) related to surface coal mining operations in Appalachia

This study investigates the environmental exposure of residents of a community in southwest Virginia to respirable concentrations of dust (PM-10 i.e. PM10) generated by trucks hauling coal from surface coal mining operations. The study site is representative of communities in southwest Virginia and other parts of Appalachia that are located in narrow hollows where homes are placed directly along roads that experience heavy coal truck traffic.Preliminary air sampling (Particulate Matter i.e. PM10) was conducted for a period of approximately two weeks during early August 2008 in the unincorporated community of Roda, Virginia, at two locations (about a mile apart along Roda Road (Route 685) in Wise County, Virginia). For the purposes of this study (a combination of logistics, resource, and characterization of PM) we sited the PM samplers near the road to ascertain the micro exposure from the road. The results revealed high levels of PM10 (the mean adjusted 24-h concentration at the Campbell Site=250.2μgm−3 (±135.0μgm−3); and at the Willis Site=144.8±60.0μgm−3). The U.S. 24-h national ambient air quality standard for PM10 is 150μgm−3. Elemental analysis for samples (blank-corrected) collected on Quartz filter paper (on one randomly selected day) at both the sites revealed the presence of antimony, arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, mercury, nickel, selenium. Electron micrographs reveal the morphology and habit (shapes and aggregates) of the particulate matter collected.

Bench- and Pilot-Scale Testing of Ion Exchange and Zero Valent Iron Technologies for Selenium Removal from a Surface Coal Mine Run-Off Water

Bench- and Pilot-Scale Testing of Ion Exchange and Zero Valent Iron Technologies for Selenium Removal from a Surface Coal Mine Run-Off WaterBench- and pilot-scale testing was conducted for removal of selenium from runoff water at a surface coal mining operation in 2011. The study focused on two technologies for selenium removal: ion exchange (IX) and zero-valent iron (ZVI). The IX bench- and pilot-scale results showed that IX is a feasible means for treating selenium, provided the selenium is primarily in the selenate [Se (VI)] form...Author(s)Ken MartinsJeremy JohnsonKaren LeberRangesh SrinivasanBo HellerSourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Sep, 2012ISSN1938-6478DOI10.2175/193864712811740693Volume / Issue2012 / 17Content sourceWEFTECCopyright2012Word count178

Field Service Conditions of the Oldest Corrugated HDPE Pipe Culvert under Ohio’s Roadway

AbstractA research institute at Ohio University recently conducted a comprehensive study on highway culvert structures for the Ohio Department of Transportation. During the study, a number of thermoplastic pipe structures under Ohio’s highways were inspected and rated. One of the thermoplastic pipe structures was a 0.61-m-diameter (24-in.-diameter) corrugated high-density polyethylene (HDPE) pipe under State Route 145 in Noble County, Ohio. What was unique about this pipe structure was that it was the oldest thermoplastic pipe culvert in service in Ohio. The pipe was installed under a shallow cover in 1981. The Ohio University team visited the culvert site in 2004 and inspected the pipe structure thoroughly. It was inspected again in June 2010. Drainage water entering the culvert was acidic, indicating the influence of a nearby surface coal-mining operation. The pipe structure had moderate amounts of deflection under the roadway, but overall it appeared to be in satisfactory condition. In 2004, a short pi...

Coal mining regulations

The U.S. Department of the Interior (DOI) announced on 18 November measures to strengthen the oversight of state surface coal mining programs and to promulgate federal regulations to protect streams affected by surface coal mining operations. DOI's Office of Surface Mining Reclamation and Enforcement (OSM) is publishing an advance notice of a proposed rule about protecting streams from adverse impacts of surface coal mining operations. A rule issued by the Bush administration in December 2008 allows coal mine operators to place excess excavated materials into streams if they can show it is not reasonably possible to avoid doing so. “We are moving as quickly as possible under the law to gather public input for a new rule, based on sound science, that will govern how companies handle fill removed from mountaintop coal seams,” according to Wilma Lewis, assistant secretary for Land and Minerals Management at DOI.

English

Relationships between electrical conductivity (EC) and sodium adsorption ratio (SAR) changes over time in reconstructed soils at surface coal mining operations are insufficiently documented in the literature. Some minesoils (i.e., rootzone material) are classified as saline, sodic, or saline-sodic and have been considered unsuitable rooting media for establishment of native vegetation. Weatherable minerals (e.g., pyrite, calcite, gypsum, and other geologic substrates) commonly present in minesoils can mitigate the effects of elevated SAR levels by maintaining or increasing electrolytes in the soil and provide sources of exchangeable calcium and magnesium. Coversoil (i.e., topsoil) enhances this mitigation through physical and chemical buffering of minesoils. Weathering characteristics of minesoils and rooting patterns of key reclamation species were evaluated at sites from three surface coal mines in northwestern New Mexico and northeastern Arizona. Unweathered minesoils were grouped into 11 classifications based on EC and SAR. Comparison of saturated paste extracts from unweathered and weathered (6 to 14 years after reclamation) minesoils show significant (p < 0.05) reductions in SAR levels and increased EC. Weathering increased the apparent stability of saline and sodic minesoils thereby reducing risks of aggregate slaking and clay particle dispersion. Root density of fourwing saltbush (Atriplex canescens), alkali sacaton (Sporobolus airoides), and Russian wildrye (Psathyrostachys junceus) were generally unaffected by increasing minesoil EC and SAR levels. Saline and sodic minesoils can be successfully reclaimed when covered with topsoil and seeded with salt tolerant plant species.

English

Relationships between electrical conductivity (EC) and sodium adsorption ratio (SAR) in reconstructed soils at surface coal mining operations are poorly documented in the literature. Research has focused primarily on agricultural and range soils. Chemical and physical properties of reconstructed soils are unique and quite different from natural soils formed over hundreds of years through pedogenic processes. These differences largely occur because relatively unweathered overburden is exposed during mining processes and subsequently used as a lower root-zone medium (minesoil) during soil reconstruction. Some of these materials are classified as sodic and therefore are considered unsuitable rooting media for establishment of native vegetation. Weatherable minerals (i.e., pyrite, calcite, gypsum, and other geologic substrates) present in minesoils can effectively remediate or mitigate an elevated SAR condition by maintaining EC levels in the soil solution to promote clay particle stability and by providing sources of exchangeable calcium and magnesium. Coversoil (e.g., topsoil) enhances remediation through physical and chemical buffering between sodic root-zone material and the reconstructed soil surface. A laboratory core-study was used to evaluate weathering potential of 10 minesoil materials from three mining operations in the Southwestern United States. Cores were prepared with 15 cm of coversoil over 30 cm of minesoil and subjected to simulated precipitation. Chemical evaluations of weathered materials show significant reductions in EC and SAR and overall improvement of minesoil quality. Chemistry of drainage water from three coversoils shows these materials behave as a chemical buffer above the underlying sodic materials. Coversoils provide a source of calcium and other electrolytes that promote physical stability and enhance remediation of sodic minesoil materials.

Benchmarking and management of fugitive dust emissions from surface-mine haul roads

Dust generation from haul roads is a problem for most surface coal-mining operations and especially those in semi-arid and arid areas. For these mines, which rarely have optimally designed and maintained roads, classifying different levels of dustiness, quantifying the impact on safety and assigning priorities within the constraints of limited capital and manpower are problematic. Techniques have now been developed for the description of fugitive dust emissions associated with ultra-heavy mine haul trucks running on unpaved mine haul roads. Benchmarks are established as five degrees of 'dust defect' for trucks travelling at 40 km/h, and computer models are used to assess the likely dustiness of haul roads as a function of surface loading of fines, traffic types and volume, together with various material parameters. For a typical South African Highveld colliery haul road reapplication intervals for water spraying were found to vary from 33 to 63 minutes for rear-dump trucks and from 21 to 41 minutes for bottom-dump trucks between summer and winter operation. The models can be applied, in conjunction with the results of quantitative exposure profiling, in management and mitigation strategies for water-based spraying.

Abatement of acid mine drainage by capping a reclaimed surface mine with fluidized bed combustion ash

A watershed in north-central Pennsylvania was being polluted by acidic drainage from a surface coal mining operation. To abate the pollution, a thick cement mix based on fluidized bed combustion (FBC) ash was applied to the regraded surface, after which the site was covered with topsoil and revegetated. The FBC ash cement layer serves as an aquitard, preventing infiltrating rainfall from reaching acid-forming units in the backfilled mine. The horizontal components of ground water flow to the site are negligible. Consequently, acid formation was inhibited, and the concentrations of Fe, Mn, and Al were diminished substantially below levels present in the ground water and surface discharges before the application of the fly ash. Cr, Cu, Pb, Ni, and Zn are not present at detection limits in the receiving stream, while only a trace of Se is present. Benthic macroinvertebrate populations have improved markedly.

96/06563 Analysis of quartz exposure data obtained from underground and surface coal mining operations

96/06563 Analysis of quartz exposure data obtained from underground and surface coal mining operations

Analysis of Quartz Exposure Data Obtained from Underground and Surface Coal Mining Operations

Abstract The Mine Safety and Health Administration (MSHA) yearly performs quartz analysis on approximately 9000 respirable coal mine dust samples collected for various occupations in U.S. coal mines. All occupational quartz exposure data gathered by MSHA since 1985 have been compiled and analyzed to characterize current occupational exposures to quartz; to determine if the quartz percentages of samples collected for different occupations have changed during the period 1985 through 1992; and to study the intramine variability associated with quartz sample percentages of selected occupations. Analysis of the occupational data shows that regardless of the type of coal extraction process used, there are a substantial number of occupational samples that contain greater than 5 percent quartz and show quartz exposures that exceed 100 μg/m3. In underground mining operations, approximately 30 percent of the samples collected at the continuous-miner operator and continuous-miner helper occupations on continuous-min...

Artificial intelligence in surface coal mine planning

ABSTRACT Artificial intelligence and knowledge based expert systems can be utilized for planning of surface coal mining operations. Approach to planning of surface coal mines involves property selection to meet consumer coal quality requirements, site characteristics, equipment analysis, and mine parameters. The architecture of the Expert System consists of the user, the knowledge base, and the inference engine. Interfacing of the Expert System with other conventional computer programs for coal mine design can be arranged.

A mathematical programming approach for scheduling equipment in a surface coal mining operation

A mathematical programming model for scheduling open pit mining was developed and validated using data from a surface mining operation. A two-phase solution procedure was used involving repeated evaluations of an integer scheduling model and a simple transportation model.

Using mathematical programming to develop optimal overburden transport strategies in a surface coal mining operation

ABSTRACT In this paper we study the problem of transporting overburden in a surface coal mining operation. A mathematical model is used to capture the overburden transport operation. This model is solved using a two-phase method and is used to analyze different transport strategies.

Personnel aptitude test scores as a function of age, education and job type.

A battery of personnel aptitude tests were administered and correlated with age for individuals working in skilled and unskilled jobs at a surface coal mining operation. Relationships between age and several measures of cognitive ability were significantly different when computed for skilled versus unskilled employees. Specifically, decreases in cognitive test performance with increasing age were more pronounced for unskilled workers. The partialling out of education had relatively little impact on relationships found between age and cognitive test performance for both skilled and unskilled workers.

The Computer Modelling of Surface Mining Operation

The Canada Centre for Mineral and Energy Technology (CANMET)/Calgary Coal Research Laboratory and the National Research Council in Ottawa established a joint working research group with industry to develop and test various computer models for application in surface coal mining operations in western Canada The first part of the paper deals with the problems the group experienced during the past two years especially having model specification and requirements defined and understand site management practices The second part of the paper deals with site specific development of general mine model for Trans Alta Utilities' Highvale Mine in Alberta. Described here are the development of an interactive truck/shovel model for their three pit operation, selection and application of dragline model for tandem operation with the extended bench method, criteria for operational model of the five seams operation with selective mining approach Potential model application for other mining companies are also discussed. An overall structure for interactive dynamic event-based models of surface mining operation is introduced. Examples of logic diagrams for some selected events are also presented