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By J. Kendall Hales

Jan 1, 2005

By Gloria Fernández

La contaminación por drenaje ácido de mina se considera como la responsabilidad ambiental y económica más grande que actualmente enfrenta la industria minera. En ese sentido, se delimita las áreas afectadas mediante la perforación de pozos de monitoreo a través de un estudio geofísico previo. Por ello, el presente trabajo señala los métodos geofísicos como herramientas que pueden ayudar a delimitar y mapear las zonas afectadas por la contaminación proveniente de drenaje y filtraciones que va desde canchas de relave, pilas de lixiviación a minas abandonadas, etc.

Aug 25, 2002

By H. M. Maturano

"Los métodos geoeléctricos de detección de fugas se utilizan en obras de ingeniería civil con el fin de mejorar los sistemas ambientales y de producción En ese sentido, el presente texto señala los métodos aplicados para detectar daños en la geomembrana expuesta como el método Lanza de Agua y Bipolar. El primero consiste en la aplicación de un potencial eléctrico entre el suelo ubicado debajo de la geomembrana y el agua esparcida en la superficie de la misma, mientras que el segundo, expuestas, mientras que el método Bipolar tiene como finalidad localizar fugas en la geomembrana luego de haber sido recubierta con algún tipo de material. Para el caso de plataformas de lixiviación, se han realizado cálculos de costo/beneficio sobre la aplicación de programas de detección de fugas, concluyendo que resulta económicamente rentable su ejecución comparada con las pérdidas de solución rica en mineral a través de los agujeros por largos períodos."

May 1, 2016

By H. Wotruba, K. Neubert

Dual-energy X-ray transmission (DE-XRT) imaging is known from safety luggage inspections at airports. The use of DE-XRT technology for sorting applications in the primary raw materials industry has been the subject of numerous investigations. Beside other metal ores, X-ray transmission sorting is already used for the preconcentration of tungsten ore, gold ore and coal. The applicability of DE-XRT sorting is limited to ore types where differences in metal concentrations are measurable, based on an interpretation of X-ray images. Metal contents in particles occur in large varieties in terms of concentration, grain sizes, spatial distribution and mineralogy and therefore influence the X-ray absorption. As a result, each ore has to be tested individually for its suitability for DE-XRT sorting. The objective of current research at the Department of Mineral Processing (AMR) at RWTH Aachen University is to assess parameters influencing the detectability of rare earth oxides. Two approaches were followed: (1) Practical test work, based on artificial ore samples of defined compositions and (2) Computer-based simulation of absorption features of identical particle compositions. In total, more than 300 artificial samples of various compositions and metal grades were produced and X-ray images from DE-XRT sorting were analyzed. Results from the DE-XRT sensor were put into correlation with metal grades and particle sizes, to analyze influences and limits on the detectability of rare earth oxides. In addition, a new approach was tested in which the X-ray absorption of particles of various compositions was determined based on a Monte Carlo (MCNP) simulation. During the simulation, similar compositions, as used for the artificial samples, were tested and the X-ray absorption behavior during DE-XRT sorting was determined. A comparison of results from both approaches is used to assess the applicability of the MCNP-simulation for the prediction of the X-ray attenuation behavior during DE-XRT sorting.

Jan 1, 2016

By Oscar Ccaccya Anca

Se viene realizando monitoreo de condición a las Zarandas Vibratoria en Chancado Secundario y Terciario, para lo cual se aplica diferentes técnicas de Análisis, entre las cuales está la técnica de Vibración, que, gracias a una serie de configuración respectiva y filtros del valor adquirido, puede apreciarse el deterioro progresivo para su pronta intervención.

Sep 1, 2017

By Xianxin Shi

In surface electrical exploration the high resolution earth resistivity method (HRRM) is a very effective method for detecting abandoned drift mines workings. When the abandoned mines are more than 500 ft (150 m) deep, its detection capability reduces greatly and requires more effort to implement. In Yan Quan coal mine, Shanxi province, we tried to adapt this method for underground application. Two survey lines were designed with the spacing of current and potential poles 20 m and 10 m, respectively and measuring points at 2m. The measurement radius of I line and I1 line were 140 m and 60 m, respectively, and the infinitely far pole was 1200~2000 m from the survey line. (Note the I and II lines are located on the north and south ribs of main tunnel, respectively). The survey results showed that abandoned workings were located at 25-70m, Survey Line I and at 80-1 10m, Survey line 11. Based on this finding, the longwall panel gateroads and set up entry were properly located thereby providing safe mining of the No. 15 Coal seam. Key Words: Abandoned coal mine, High resolution earth resistivity, Underground electrical exploration

Jan 1, 2005

By Wu Jian-tao, LI Guo-wei

"The Cement Mixing Pile (CMP) quality assurance assessment is an important programme in evaluating the efficiency of foundation improvement. Coring is the current specified method of quality assessment in China which has the shortcomings of long cycle, high cost and low efficiency. The field and laboratory test show that the regular cone penetration test can only detect maximum of 4m of effective detection depth in CMP. In contrast, the method of cone penetration test in the reserved hole can detect the quality continuously along the pile at any depth. The tip resistance of reserved hole penetration in the 7th day has good linear relationship with unconfined compressive strength in the 28th day. The slope of linear relationship decreases with the increasing of clay particles content.INTRODUCTIONThe method of Cement Mixing Pile (CMP) is often used to improve soft soil foundation in highway construction, with the major purpose of reducing settlements under embankments (Bruce et al., 2000),which is a form of what is known as the Deep Mixing Method (Bruce et al., 2013). The CMP technology spread quickly in China in the 1980s. CMP quality assurance assessment is an important programme in evaluating the efficiency of foundation improvement. Coring is the current specified method of quality assessment in China (China Academy Of Building Research, 2002). The method of Coring is perceived in some quarters that samples will provide lower strengths given the distress caused to the core during drilling and extraction (Bruce et al., 2002).The cone penetration test CPT can provide continuous measurements of the penetration resistance, sleeve friction at the tip of the probe, which has advantages of simple operation, low cost and high efficiency compared with coring. However, CPT tests have not been established to assess CMP in Sweden because of difficulties in maintaining verticality (Larsson, 2005). In Finland and Norway, however, CPT tests are commonly used (Halkola, 1999). One of the disadvantages of CPT is the tendency of the cone to steer out of the column (Porbaha et al., 2003). Darya Mokrousova (2010) states this tendency to deviate can be overcome by pre-boring and starting the penetration test from the base of the pre-bored hole. Sheng Haiyang (1999) found that probes may be deflected out, sometimes even at small penetration depths, and may not give a complete inspection of the pile. Liu Songyu et al. (2003) suggested that the Standard Penetration Test (SPT) is an effective way to evaluate the strength and quality of stabilized soil-cement columns. In general, Regular CPT can’t test the full length of CMP, and SPT still needed drilling which causes discontinuous detection. From the existing standard of China, core sampling compressive strength test is the main method, evidently, coring displays a longer test cycle, high cost and low efficiency. Therefore, an improvement of CMP quality assessment, by conjuring a fast and reliable detection and evaluation method, is necessary. The aim of this paper is to research the feasibility of using CPT in assessing the quality of CMP and presents an improved CPT method."

Jan 1, 2015

By Michael S. Wieland

This report discusses measurement techniques utilized in and trend results obtained from research on delay blasting malfunctions in underground coal shots at the U.S. Bureau of Mines. Charge malfunctions occur during delay blasting in underground or surface mines, rendering the explosive operations more hazardous and less productive. Modern instrumentation techniques reveal several types of reduced charge performance, resulting from cross-hole interactions. Two receptor (wave-target) charge malfunctions were detected in fourteen shots that were undeniable. There were other receptor charges that exhibited under-performance by registering out-of-tolerance or noticeably reduced detonation rates. Delay blasting generates tremendous shock waves and rifting forces that fracture and heave the surrounding stratum and unfortunately damage remaining unfired charges. This report contains two graphs, representing roughly 1% of total records, that show donor (wave-source) charge shock waves and rift (reaction-to-heave) compressions. These debilitating wave impacts precipitate modes of reduced charge performance ranging from weak detonations or misfires to sympathetic detonations. As recognized from previous research, impaired charges react poorly, perform less useful work, and yield fumes with atypical higher toxicity.

Jan 1, 1995

By Y. H. Alghamdi, A. D. S. Gillies

"INTRODUCTION Background Diesel Particulate Matter (DPM) has been a critical issue during the last decade in underground mines. This problem is threatening the health of mine workers, as well as the mine’s productivity. It has been confirmed that the diesel engine exhaust is the main source for the diesel particulate matter (DPM), and that it has the highest impact in raising carbon monoxide, carbon dioxide, oxide of nitrogen, and hydrocarbons in the underground environment. Miners who are exposed to this kind of emission are at high risk for developing lung cancer and other lung diseases. The Mine Safety and Health Administration (MSHA) has issued standard rules to regulate diesel emissions in underground mines. The final ruling confirmed in 2008 that the total carbon should not exceed 160 µg/m3. (MISHA, 2008) Monitoring DPM in underground mines has become important to ensure compliance with the MSHA regulations. There are many different types of DPM monitoring systems that are currently being used in underground mines. Two methods are typically used for DPM sampling: the personal sampling method or the direct exhaust sampling method, which takes a direct sample from the engine’s tailpipe. Many mines do not recommend using the direct exhaust sampling method since it involves complex measuring equipment and procedures, as well as it is not regulated in the United States or Canada. Thus, the personal sampling method is the preferred method in many mines when taking DPM samples. Even this method includes many variations, such as the Respirable Combustible Dust (RCD) method and the method devolved by the National Institute for Occupational Health and Safety NIOSH 5040. The NIOSH 5040 method is the preferred method overall because it gives more accurate measurements compared to the other methods. This method does not allow organic carbon sources other than those coming from diesel engine exhausts to interfere with the measurements, which otherwise would lead to overestimating the actual amount of the DPM in the mine environment. An impactor feature in the cassette, which holds the samples in the instrument, characterizes this method. Since the diesel particles are less than 0.9 micron, this impactor does not allow particles more than 0.9 microns to be collected in the cassette filter. The cassette is then analyzed in a lab and the concentrations of organic carbon (OC), elemental carbon (EC), and total carbon (TC) are determined. Lately, the National Institute for Occupational Safety and Health (NIOSH) has developed a new instrument that can use the same concept of NIOSH 5040, but with instant measurements of elemental carbon. It utilizes laser radiation with the cassette so it can give a real time measurement. The real time measurements give instant information about the underground environment that will allow the mining engineer to take immediate action and enact plans instead of waiting for results from the laboratories where NIOSH 5040 method may take several weeks to get the measurements."

Jan 1, 2016

By Raymond M. Stateham

A portable, handheld infrared scanner has been used to detect abnormal surface temperature on dumps of flood-generated trash near Wilkes-Barre, Pa. Three of eight dumps examined had thermal anomalies on the surface, indicating temperature buildup at depth. The anomalies found with the scanner were verified by measurements with a thermocouple probe or a carbon monoxide detector. One week after the investigation was completed, open fire broke out at the site of one of these thermal anomalies; about 6 weeks after the investigation, a thermal anomaly in another dump was verified when a trench was excavated in the dump.

Jan 1, 1973

By N B. McCaffrey, V Glenn, C Johns, P D. Erskine, A T. Fletcher

"Underground coal mining is the dominant method of extracting thermal and coking coal in the southern and western coalfields of New South Wales. Monitoring mining-related subsidence forms an important component of environmental impact assessments and subsidence management plans, particularly when there are conflicts between the interests and requirements of mining and environment and community groups. However, there are few specific guidelines for monitoring the impacts of subsidence on terrestrial and aquatic ecosystems, leading to inconsistent policy approaches and highly variable abilities of monitoring programs to accurately detect biological change.This paper highlights the use of a conceptual framework to guide the development of a long-term ecological monitoring program at an underground coalmine in the Western Blue Mountains, New South Wales. Two pilot studies are described: determining the level of observer agreement to assess the condition of a vulnerable tree species (Capertee Stringybark) comparing field sampling methods for detecting a rare heath shrub, Epacris muelleri, using a power analysis to determine sampling intensity requirements.These examples demonstrate that investment in initial pilot studies to test different monitoring approaches can have long-term benefits for stakeholders by more confidently being able to detect potential impacts.CITATION:McCaffrey, N?B,?Glenn, V, Erskine, P?D, Johns,?C?and Fletcher, A?T, 2014. Detecting long-term ecological impacts of subsidence from underground coal mining – a tale of two pilot tests, in Proceedings Life-of-Mine 2014, pp 139–152 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By Rene Padilla, Siyanda B. Mngadi, Gerrie van Aswegen, Peter Stonestreet

While many mine tunnels are developed through ground that must be riddled with the sources of small (and larger) mining induced seismic events, recorded by the mine seismic monitoring systems, we do not see planar discontinuities classified as seismic sources in the geotechnical databases. Here we list criteria that may be useful to identify discontinuities in drill core which are dynamic slip surfaces, parts of mining induced seismic sources. Such shear rupture surfaces in core would generally be powdery, cohesionless, and rough on cm scale. Finely broken rock and rock flour may be found in the core boxes at the discontinuities. Slickensides would be soft (easily destroyed) and kinematically consistent with the local stress field. In some cases, a cross fabric would be present, orthogonal to the slickensides, being the intersections of en-echelon extension fractures, within the dynamic shear zones, with the shear zone walls.

Apr 26, 2022

By Jami M. Girard, Ed Mchugh

Slope stability accidents are one of the leading causes of fatalities at U.S. surface mining operations. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is currently conducting research to reduce the fatalities associated with slope failures. The purpose of this paper to discuss some of this research and to present potential new technologies for slope monitoring and design. The paper also briefly discusses various warning signs of slope instability, introduces the most common slope monitoring methods, describes the limitations of various slope monitoring systems, and presents some field results using some of this new technology.

By L Lachance, F Flament, D Leroux, S Gariépy

The pervasiveness of poor sampling practices in and around mineral processing plants could seem intriguing in view of the various documented evidences both for causes and consequences. To this extent, this paper revisits the well-documented but lesser-known fact that failure to care sufficiently about how samples are selected and managed is the mother source of almost all sampling biases. The authors believe that the potentially huge leverage between causes and consequences as well as the diversity of people involved in sampling call for a globally integrated solution rather than for a point solution. Such a globally integrated solution has already been put forward by the AMIRA P754 Metal accounting – code of practice and guidelines (AMIRA, 2007) that inherently requires accuracy to be targeted, measured, reported and managed. Furthermore, always in order to avoid a point solution, several layers of protection against biases must be put in place with each one involving a different ownership whenever possible. This is exactly the role intended by the supervisory bias detection method described in this publication. It is based on the continuous monitoring of the expected value of reduced residuals obtained from statistical data reconciliation conducted in a metal accounting context. This supervisory bias detection method is developed in full details after which Monte Carlo simulations are done on a mineral processing plant example for showing how it can be successfully applied for detecting hidden biases.CITATION:Lachance, L, Leroux, D, Gariépy, S and Flament, F, 2014. Detecting sampling biases in metal accounting, in Proceedings Sampling 2014 , pp 109–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By Tara Bajpayee

Modern, highly productive underground mining operations need to assure the safety of their workforce by understanding where major strata fractures and roof failures could occur. Mines depend on a host of tools to assess ground instability. In-mine microseismic monitoring systems with sufficient number of sensors have also been used to provide this information. These in-mine systems must be robust in design and moved regularly to keep up with the mining advancement. System performance issues depend on maintaining ever increasing cable runs, preventing component damage from mining activities (scaling, blasting, etc.) and avoiding signal degradation due to interference from mining equipment (fans, trucks, electrical equipment, etc.). A potential solution is to use a surface based monitoring system having sensors placed in boreholes above and adjacent to the underground mine workings. These sensors must be capable of detecting and locating strata fracturing associated with rock failure events. A great advantage of a surface based monitoring system is its independence from the underground mine infrastructure. There is less concern with cable maintenance problems, signal degradation by interference from mining activity, or loss of power from the mine?s power grid. The disadvantages include the cost of drilling boreholes and challenges associated with placing sensors in the boreholes, maintaining radio communication and solar power, and public interference (vandalism, etc.). This paper describes a case study where a surface based microseismic system, using triaxial geophones in boreholes drilled from the surface, was deployed at a large limestone mine. The system was operational during a roof fall that occurred in October 2007. It detected the first rock fracture event 17 minutes before the rock fall event. The geophone array was sensitive enough to identify all large rock fracture, impact, and blast events as well as medium size rock fracture events occurring close to the geophone array.

Jan 1, 2008

By M. Sukhram, S. A. Argyropoulos

"In the aluminum and steel processing industries there is a need for velocity sensors to measure the flow characteristics of liquid metal. This paper will present a sensor and an inverse heat transfer technique to determine the direction of velocity in flowing liquid aluminum. Experimental research work with the sensor involving liquid aluminum was conducted, using the Revolving Liquid Metal Tank at the University of Toronto, which rotates 50 kg of liquid aluminum with velocities up to 0.35 m/s. Experimental data for various magnitude of velocity demonstrate that the sensor records different thermal profiles under different fluid flow conditions. Using the transient temperature information and the inverse technique, the direction of velocity of the molten aluminum flow field can be inferred. INTRODUCTIONOur research at the University of Toronto has focused on developing invasive sensors to determine the velocity of high temperature liquid metals. High temperature in this setting is defined at VALUES (in excess of 660 °C. The discussion which will persist in this manuscript involves detecting the direction of flow in liquid aluminum using an inverse heat transfer technique. We first reported on the sensor which is used in this article in the following two publications (Sukhram and Argyropoulos, 2011a; Sukhram and Argyropoulos, 2011b). The motivation to perform this research is due to the lack of sensors available to characterize the conditions within a high temperature liquid metal reactor/vessel. A report conducted by The Minerals Metals and Materials Society (TMS Energy 2011) has suggested that the introduction of sensors into molten metal processing environments has the potential to increase process efficiency up to 15%. Such sensors will aid in the understanding of high temperature liquid metal processing operations with the goal to implement more efficient process design and practice."

Jan 1, 2012

By F. Sime, X. Wang, J. D. Miller, T. Akinseye, S. Assemi, L. Pan

Respirable coal mine dust (RCMD) is a complex mixture of carbonaceous and mineral particles with a variation in size and shape. Accumulation of RCMD in the lungs of underground coal miners results in severe respiratory damage and ultimately progressive pneumoconiosis known as the black lung disease. The occurrence of the black lung disease dropped to a low of 2.1% in 1990s but has increased to 3.1% in 2000s [1], prompting more research on coal mine dust mitigation. In addition to surveying the impact of new mining technologies on the size of generated dust and exposure measurement, a comprehensive characterization of physico-chemical properties of RCMD particles are essential for a better understanding of the adverse health effects of coal mine dust. Such vital factors include particle size, surface charge, morphology, composition, and agglomeration state. The respirable fraction of RCMD, has been designated as particles < 10 μm in diameter, and almost all studies on the RCMD toxicity have focused on micron-sized particles. However, recent toxicological studies have shown that nanoparticles (particles with one dimension less than 100 nm) can have a magnified toxicity compared to the larger particles with the same chemistry [2]. Nanoparticles have a much higher specific surface area compared to the same mass of larger particles and are thus more reactive. Most micron-size particles can be cleared by the body’s defense mechanism. However, inhaled nanoparticles can easily deposit in all regions of the respiratory tract and can translocate to vital organs. [2].

Mar 2, 2022

By P. L. M. Wong, N. W. Johnson

Surface analysis by X-Ray Photoelectron Spectroscopy (XPS) of samples taken from the galena flotation section of the Hilton Concentrator of Mount Isa Mines Limited are presented. Flotation rate and pulp chemical data taken during the sampling period are also presented and discussed. Surface analysis suggested that, under normal operating conditions, an overlayer of precipitated calcium sulfate existed at the surface of the sulfide minerals. In particular, there was a decrease in the surface concentration of calcium sulfate for the concentrate samples relative to that occurring on the tailing samples. This suggests that the flotation process was selective against minerals which have calcium sulfate predominating at the surface. Heterocoagulation of hydrophilic calcium sulfate on to the galena surface considerably reduced galena flotation rate. Methods to control calcium sulfate precipitation, which include sodium carbonate treatment of the pulp, are also discussed. Sur- face analysis results of samples taken from the Hilton Concentrator during sodium carbonate addition to the grinding circuit are also presented. This shows clear evidence for the removal of calcium sulfate from the mineral surfaces without concomitant surface precipitation of calcium carbonate. Reasons for the apparent dispersion of precipitated calcium carbonate are discussed. Galena flotation rate was increased by the addition of sodium carbonate apparently due to the removal of interfering calcium sulfate.

Jan 1, 1995

By R. D. Hamilton, W. J. Miles

In 1987, the International Agency for Research on Cancer designated crystalline silica as a 2A probable carcinogen. As a result, crystalline silica is regulated under the Hazard Communication Standard as a probable carcinogen at a concentration of 0.1% or greater in the workplace. Crystalline silica will be listed as "reasonably anticipated to be a carcinogen" by the National Toxicological Program. This designation of crystalline silica as a probable carcinogen has created major issues for the mineral and chemical producer, including labeling, hazard communications, marketing a material with potential hazard exposure, and potential liability. The State of California also regulates crystalline silica under Proposition 65 in products as a carcinogen, based upon the IARC determination that it is a probable carcinogen. More federal and state regulations are anticipated as a result of the IARC classification of crystalline silica and its subsequent federal regulation. Respirable crystalline silica has been regulated as a hazardous dust for many years by OSHA. This regulation was initiated to prevent silicosis, another occupational disease. OSHA has established monitoring devices for determining the concentration of airborne respirable silica in order to measure exposure to this substance. The accurate determination of the crystalline silica content is critical to dealing with these health risks and regulations. In the past, crystalline silica was considered to be safe and, because of its ubiquitous nature, little effort was made to determine or quantify its presence in most materials. The Hazard Communication Standard requires that a1l products containing 0.1% or greater crystalline silica must be properly labeled for this material and its hazard. Unfortunately, the 0.1% threshold was not chosen on the basis of established analytical capabilities for crystalline silica, but results from general limits for potentially carcinogenic chemicals and substances. Numerous methods have been developed for the determination of crystalline silica in a variety of products. However, these methods are not generally applicable since they must be specific for silica in any of its crystalline states and not just for total silica content. Chemical tests for silica are not difficult and quite accurate at the 0.1% level; however, in addition to its crystalline phases, it occurs in amorphous phases and in a wide variety of crystalline and amorphous silicates. In general, there is little correlation between total silica content and crystalline silica.

Jan 1, 1991

By Gift Makusha

Surface subsidence associated with coal mining activities in the Mpumalanga Province of South Africa changes the natural environment in several ways, and current challenges for mining companies include rehabilitation of the natural environment and the prevention of further degradation. To monitor the spatial and temporal evolution of surface subsidence, traditional fieldbased monitoring approaches such as GPS and spirit leveling are employed at a number of locations. However, the resulting measurements are point-based, and frequent revisitations are necessary to map the evolution of surface subsidence basins over time. To address these limitations, differential interferograms derived from repeat-pass satellite-borne synthetic aperture radar (SAR) systems were tested for their ability to measure and monitor surface deformation. The SAR data was captured by the European ERS-1 and ERS-2 satellite and covered a timeframe between 2008- 09-15 and 2008-09-15. The resulting interferograms revealed several features indicative of surface subsidence. Ground truth data confirmed the presence of a subsidence basin, detected using differential interferometry techniques during the 35-day period between April 12, 2008 and May 17, 2008; a maximum vertical deformation of 3.2 cm (1.3 in) was recorded. Interferometric monitoring revealed an eastward migration of the subsidence basin between June 2, 2008 and September 15, 2008 with an additional 4.7 cm (1.9 in) of subsidence observed. This migration coincides with the advance of the working face of the mine during this period. Finite element modeling will be performed in order to model the rates and evolution of surface subsidence haloes as underground mining advances. These presented results demonstrate the ability of interferometric synthetic aperture radar techniques to measure surface subsidence as well as the monitoring of the evolution of subsidence basins over time. This implies that the technique could be included, together with traditional field-based surveying techniques, in an operational monitoring system. With knowledge on deformation rates and subsidence basin evolution, informed decisions on current and future infrastructure development can be made and remedial actions and prevention strategies can be formulated for the problems associated with environmental degradation.

Jan 1, 2011