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By David E. Nicholas

Design of underground openings is becoming more critical as the mine deposits become lower in grade, initial investments increase, ore depth increases, additional safety regulations come into law, and increased ore recovery is required for conservation of minerals. Stability of these openings is dependent on the strength of the rock mass and the pre-mine stress field. The rock mass is composed of solid blocks of rock (rock sub- stance) and structural features (faults, joints, bedding, etc.). Methods of testing the rock mass strength are improving and be- coming more common, however it is difficult to justify the high cost of large scale testing for an initial mine design. An alternative to testing the rock mass is to measure the rock substance and the structural features separately, and then combine them to estimate the rock mass strength. The rock mass strength will vary depending on the orientation of the opening with respect to the structural features. The other factor affecting the stability of underground open- ings is the pre-mine stress field. Methods are available to measure "directly" the pre-mine stress in competent and relatively massive rock. These methods are costly to employ, therefore, they may not be justified in an initial study. The pre-mine stress field can be estimated based on the structural relationships formed from past tectonic events.

Jan 1, 1976

By E Macmillan

For any processing plant there will be deleterious elements or minerals which affect production or quality, and a strategy to predict their occurrence and mitigate their impact is required. An early objective of the Olympic Dam geometallurgy program was prediction of the acid consumption and gelling behaviour of the ore, which affects leach recovery, throughput and circuit availability. The geometallurgical test program measured the response of a wide range of ore types, and then relationships between mineralogy, metallurgy and chemistry were developed. Thus the drivers of acid consumption and triggers for gelling events could be described in ways that were meaningful to plant operations.To enable optimisation of the mine planning and ore blending processes, the parameters driving metallurgical response must be translated to the block model. Data support is critical in populating a block model. Assay information is easily obtained, but mineralogical and metallurgical information is more expensive and time consuming to collect. Hence population of a block model with mineralogical and metallurgical values using a conventional geostatistical approach is not always possible.An alternative approach employed at Olympic Dam was the development of a suite of assay-to-mineral algorithms. These algorithms were calibrated using all available mineralogical information, and this enabled the calculation of mineral abundances for more than 1.5 million assayed samples. Estimation of the minerals in the block model, and the generation of acid consumption values for each block could subsequently occur.The use of back-calculated mineralogy from assays as part of process model generation is an innovative tool which can be used for mine planning and optimisation and to ensure the plant does not receive any unwelcome surprises. Ultimately, one purpose of geometallurgy is to predict potential processing issues and their drivers so that these can be mitigated. A strategy to achieve this is outlined hereafter.

Sep 5, 2011

By M. K. Seguin

The study described in this paper is first centered on the determination of the physical properties (gravimetric, magnetic, electrical, and electromagnetic) o f metamorphosed iron ores of the Carol Lake-Labrador City District. Different geophysical surveys available in the Carol Lake-Wabush area were interpreted quantitatively and the dimensions, attitude, and tonnage of the ore bodies investigated were determined. A geophysical-statistical study was undertaken which permitted the determination of the grade of iron, magnetite, and, subsequently, specularite in the ore bodies. A discussion of the theory and logical progression of the study and the application of the results to actual geophysical data is presented. The conclusions, which are of real significance from the economic standpoint, may be predicted from the data obtained from geophysical surveys before any diamond drilling is undertaken. An integrated interpretation of this type is useful in planning future exploration work and selecting the most favorable geological structures. It also serves as a guide to minimize and determine tonnage drilling patterns. The general conclusion that a restricted range of residual gravity and magnetic anomalies are a key to exploration is valid. Indeed large depths to the top of deposits are absent since all the ore bodies are overturned synclinal structures with tops located close to the surface. Certain irregular geometries do occur but they are not common and the alignment of the iron ore bodies is sub parallel so that magnetic anomalies are evenly reduced in the earth's magnetic field vector.

Jan 1, 1975

By J. M. McKinley

Mineral exploration programmes around the world use data from remote sensing, geophysics, and direct sampling. On a regional scale, the combination of airborne geophysics and ground-based geochemical sampling can aid geological mapping and mineral exploration. Since airborne geophysical and traditional soil-sampling data are generated at different spatial resolutions, they are not immediately comparable due to their different sampling density. Several geostatistical techniques, including indicator cokriging and collocated cokriging, can be used to integrate different types of data into a geostatistical model. However, with increasing numbers of variables the inference of the crosscovariance model required for cokriging can be demanding in terms of effort and computational time. In this paper a Gaussian-based Bayesian updating approach is applied to integrate airborne radiometric data and ground-sampled geochemical soil data to maximize information generated from the soil survey, enabling more accurate geological interpretation for the exploration and development of natural resources. The Bayesian updating technique decomposes the collocated estimate into two models: prior and likelihood models. The prior model is built from primary information and the likelihood model is built from secondary information. The prior model is then updated with the likelihood model to build the final model. The approach allows multiple secondary variables to be simultaneously integrated into the mapping of the primary variable. The Bayesian updating approach is demonstrated using a case study from Northern Ireland. The geostatistical technique was used to improve the resolution of soil geochemistry, at a density of one sample per 2 km2, by integrating more closely measured airborne geophysical data from the GSNI Tellus Survey, measured over a footprint of 65 x 200 m. The directly measured geochemistry data were considered as primary data and the airborne radiometric data were used as secondary data. The approach produced more detailed updated maps and in particular enhanced information on the mapped distributions of zinc, copper, and lead. The enhanced delineation of an elongated northwest/southeast trending zone in the updated maps strengthened the potential for discovering stratabound base metal deposits..

Jan 1, 2014

By M Zengerer

The Basil Cu/Co deposit comprises a 26.5 Mt Inferred Resource of copper and cobalt, grading 0.57?per cent Cu and 0.05 per cent Co. It lies in the Harts Range, Central Australia, within the Riddock Amphibolite of the Irindina Province. Analysis of drilling within the mineralised zone of the deposit determined a spatial association between pyrrhotite with high magnetic susceptibility and chalcopyrite, following a strong magnetic trend as determined from airborne geophysics. A study was commissioned to examine if geophysical inversion could predict the distribution of sulfide mineralisation based on pyrrhotite from drill hole intersections, as well as predicting further mineralisation at depth or in the vicinity of the deposit. Petrophysical and geostatistical analysis of drilling susceptibility and mineralisation provided a basis of property distribution inside the model. This was followed by 3D geological modelling of mineralisation based on domain kriging of drill hole susceptibility sensitivity testing of signal to source depth, and distribution was performed using 3D forward modelling. Stochastic inversion generated alternative 3D geological models, which were tested for behaviour and adherence to observed drilling data and geostatistical limitations using GeoModeller software. Predicted mineralisation distribution was compared with conventional geostatistical modelling and found to be in agreement in planar behaviour but exhibiting possibly isoclinally folded trends, with reliability increasing closer to the surface. Predictions of mineralisation at greater depth and beneath weaker anomalies were more diffuse due to small model cell size having limited influence on the signal at depth.The Blackbush uranium deposit comprises a 64.5 Mt Inferred Resource, grading 230 ppm U in the Pirie Basin south of Whyalla, South Australia. It directly overlies the radiogenic Samphire Granite and is considered a tertiary unconformity deposit. Sensitivity modelling was performed using high-resolution ground gravity to see if a deposit signature could be detected using gravity. This required 3D implicit modelling of the geology and mineralisation from drill hole data and characterisation of an associated physical property model using domain kriging in GeoModeller. Density models relied on exploiting an observed relationship between logged density and measured uranium oxide percentage. The residual gravity response of the background geology model identified the location of the uranium deposit. Stochastic inversion of the litho/property 3D model has refined the known distribution of uranium from drilling and provided structural insights into the deposit.These projects have become excellent case studies for exploiting the relationship between mineralisation and potential fields and for testing the applicability of using domain kriging of properties determined from drilling to build robust 3D geological models for stochastic geophysical inversion, leading to robust methods for exploration targeting and mineral deposit prediction.CITATION:Zengerer, M, 2014. Use of geostatistically-constrained potential field inversion and downhole drilling to predict distribution of sulfide and uranium mineralisation, in Proceedings Ninth International Mining Geology Conference 2014 , pp 281–290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Jaeheon Lee, Junmo Ahn, Doyun Shin

"Many alternative leaching systems including bacterial leaching have been introduced to avoid passivation on the surface of chalcopyrite and to increase the leaching efficiency of copper from chalcopyrite. Recently, glycine, one of the simplest amino acids, has been emerging as an efficient and environmental-friendly lixiviant to recover copper. In the present study, an alkaline glycine–peroxide lixiviant system was used to leach copper from chalcopyrite concentrate and the leaching mechanisms were also investigated by a suite of kinetic studies under different conditions. The chalcopyrite concentrate contains 28.8% copper with 30.8% sulfide sulfur. The effect of concentration of glycine and hydrogen peroxide of the leaching solution was investigated. Glycine concentration was varied from 0.5 to 1.0 M and the hydrogen peroxide concentration was changed between 3 to 5%. Leaching time and pulp density were also varied. Hydrogen peroxide is an oxidant of the system and the leaching efficiency with periodic additions of the peroxide was also studied. A mineralogical study was performed using XRD and SEM. To investigate the surface of the residue materials, XPS was used to see if any passivating layer was formed during the leaching. Detailed results from mineralogical, chemical, and metallurgical studies will be presented and discussed.INTRODUCTION The greatest global resource of copper is low-grade chalcopyrite and heap bioleaching may be the only economic option for its processing. However, formation of a passivating layer on the surface of chalcopyrite slows down the oxidation reaction and reduces the efficiency of the process."

Jan 1, 2017

By William E. Bonini

Gravitational field anomalies have been observed over many igneous intrusives of medium (4000 km2) to small (100 km2) size in outcrop area. These studies give good results because the residual anomalies can be separated from larger scale crustal anomalies and density contrasts usually are present. Although unique solutions are not possible, the analysis of the gravity anomalies can put limits upon the geologic interpretation of such bodies. Three examples in Montana, U. S. A. are discussed: (1) the Boulder Batholith, a late Cretaceous quartz monzonite series of intrusives of 4000 km2 outcrop area; (2) the Little Rocky Mountains, an up-domed area, in which an Eocene porphyry (130 km2) has intruded the Precambrian crystallines and lower Cambrian sediments; and (3) the Crazy Mountains, an Eocene diorite (100 km2), which has intruded the Paleozoic and Mesozoic sediments. In both the Boulder Batholith and the Little Rocky Mountains, intrusive rocks are less dense than the surrounding rocks and negative anomalies are found (40 and 28 mgal, resp.). In the Crazy Mountains, the intrusive is more dense than the surrounding sediments and a sharp positive residual anomaly of 42 mgal is observed. The analyses of the gravity anomalies predict that: (1) the thickness of the Boulder Batholith is on the order of 10 to 15 kms and is concave upward; (2) the Little Rocky Mountain syenite is not a simple laccolith, but is T-shaped and extends in depth to about 16 kms; (3) the Crazy Mountain diorite is not a simple small scale series of stocks, but a large connected body extending in depth 5 kms to the basement (although nothing can be said of it within the basement because there is little density contrast). The analyses of the anomalies place important limits on both the areal and depth extent of the intrusive bodies. Of all possible geophysical techniques, gravity studies offer the most promise in the determination of the shape in depth of intrusive bodies.

Jan 1, 1969

By L. Nichols, H. Keele, K. Czajewski

"The oil sands industry in northern Alberta disposes of the by-products of bitumen extraction into tailings ponds. The mix of tailings sand and mature fines, with gypsum added as a flocculent, constitute a waste stream called consolidated tailings or composite tails (CT). The two main challenges of the tailings disposal process are a chronic shortage of economical containment and the potential mobility of CT deposits in the event of breaching by, for example, long-term erosion, which makes abandonment of tailings ponds more complicated. Thick deposits of CT do not consolidate in adequate time to provide reassurance for abandonment of the CT containment facilities and that is why the containment must be adequately robust or the properties of CT improved for long-term stability. This paper addresses potential solutions to these problems by applying the gravity drainage of CT and quasi-homogeneous construction for containment facilities.Gravity drainage is suggested as a mechanism to facilitate the consolidation of CT in critical areas of the ponds by inserting internal sand layers within the body of the deposit. Critical CT areas are defined as areas around the perimeter of containment. The advantages of this solution are longterm stability of the disposal area by creation of stiff deposits around its perimeter and facilitation of reclamation efforts on its surface.The present solution for containment of CT deposits is not favourable from a materials balance point of view. In general, sand has become a valuable resource as it both forms the primary component of the CT matrix and becomes the containment building material. If sand is required for CT, less is available for dyke construction. This puts additional pressure on the industry as a whole to maximize the use of overburden and interburden for construction of tailings containment structures. Typically, only 50 percent of dry mine waste (overburden + interburden) is incorporated into dyke construction. The remainder of dry waste is stored either in waste dumps or in tailings ponds, consuming valuable in-pond space originally allocated to CT material. Quasi-homogeneous dykes are proposed to contain CT deposits rather than traditional minimum cross-section dykes built of overburden and/or cell sand. The quasi-homogeneous dyke may change the unfavourable material balance and lessen the construction constraints that are presently imposed on the mine/waste disposal process."

Jan 1, 2008

By Richard A. Thomas, Michael J. Sapko, Gary L. Mowrey, William D. Monaghan, Michael A. Trevits

Over the years, more than 20,000 mine seals have been erected in underground coal mines in the United States. Seals are used extensively in underground mines to isolate worked-out areas, active mine fire zones, and to control water inundations. Seals are most often built directly in the mine and can be fabricated from blocks made of wood or cementitious material. Recently, several explosions occurred within sealed areas of underground U.S. coal mines. These explosions, believed to be initiated by lightning strikes on the surface, destroyed numerous seals and caused considerable damage external to the sealed area. The National Institute for Occupational Safety and Health is conducting research to develop design guidelines, to investigate noninvasive techniques to characterize seal strength properties, and to evaluate seal test methods. As part of this work, a 30-ft wide, 16.1-ft tall and 4-ft thick seal was built in an underground experimental mine using cement and foamed water. Two types of noninvasive techniques are currently being investigated, namely the Schmidt Hammer for measuring compressive strength and ground penetrating radar (GPR) for detecting the presence of anomalies (e.g., voids, discontinuities) within the seal. Once these noninvasive tests were completed, the seal was subjected to destructive explosion testing. This study presents the results of the Schmidt Hammer tests, GPR scans, and the characteristics of seal failure during explosion testing.

By R. J. Sweigard

Many states are considering the need to establish or modify policy relating to the disposal of coal ash. One of the primary concerns is the impact of leachate from the ash disposal sites upon groundwater and nearby bodies of surface water. A detailed site investigation was conducted at a coal ash disposal facility associated with a power generation station. The disposal site is situated alongside a major river. Monitoring wells were installed and soil samples were taken for characterization. Groundwater models were used to simulate migration of leachate from the disposal site toward the river. Such models could be used potentially to verify regulatory compliance. This paper addresses the validation and adaptability of these models to this case and their usefulness as possible tools to be used in future environmental audits.

Jan 1, 1992

By L. Gutierrez, M. Jeldres, R. J. Jeldres

"Clays are present in a large number of mineral deposits and are commonly found as gangue. Its complex chemical structure, characterised by anisotropic surfaces, makes its presence a permanent challenge for flotation operations, increasing the reagent consumption, decreasing the quality of the concentrate, and changing the rheological properties of the system. In this context, the main objective of this research is to improve the floatability of chalcopyrite minerals in the presence of clays by using guar gum, a low molecular weight organic polymer, which acts as a surface coating agent for clays. Clay Minerals Society provided the kaolinite sample and the chalcopyrite sample was purified from mineralized rock specimens obtained from Ward’s Natural Science Establishment. Micro flotation tests were carried out in a 150 cm3 Partridge-Smith cell, using compressed air as the gas phase at a flow rate of 80 cm3/min. Potassium amyl xanthate (PAX) and methyl isobutyl carbinol (MIBC) were used as a collector and a frother, respectively. The results showed that the use of guar gum improves the recovery of chalcopyrite in the presence of kaolinite because it induces the formation of clay aggregates that settle by gravitational effects, preventing the 'coating effect' and decreasing excessive collector consumption. pH played a key role in the guar gum performance, which was most effective at highly alkaline conditions (pH 11), where the copper recovery improved from 73% to 90%. The work has significant implications for the mineral flotation in the presence of clay minerals.INTRODUCTION The mining industry is continuously confronted with challenges that alert the sustainability of the sector. There is little availability of water, the grade of the deposits are getting smaller, and the gangue is becoming more complex. Usually, clays are part of the gangue in numerous systems, including copper ore, porphyry, nickel, platinum, etc. (Senior & Thomas, 2005). The structure is mainly composed of layers of tetrahedral silica (T) and octahedral alumina (O) that join in certain proportions: 1: 1 (T-O) and 2: 1 (T-O-T) (Theng, 2012). Also, they expose two crystallographically different surfaces: the faces, which tend to be negatively charged, and the edges, which carry a charge that changes from positive to negative depending on the pH (Van Olphen, 1977). One of the most common clays in copper deposits is kaolinite, whose structure is composed of an octahedral sheet of gibbsite bound to a tetrahedral silica sheet in the ratio 1:1"

Jan 1, 2018

By David C. Kraft

A major manufacturer and user of machine tools had the need to install a screw press machine at its plant site with the following design load requirements: (1) Vertical Compression Live Load = 2000 kip (8896 kN) and Dead Load = 1000 kip (4448 kN), (2) Rotational Moment = 6600 ft-kip (8950 kN'm). The screw press machine was to be located within an existing manufacturing building. The bottom of the footing base was located 15 ft (4.6 m) below existing floor slab. A geotechnical investigation of the site indicated a 17 ft (5.2 m) thick initial stratum of stiff to very stiff clay underlain by a 14 ft (4.3 m) thick stratum of loose to medium dense sand. Beneath the sand stratum was soft rock described as weathered shale. Obvious concern was raised on the possible effects of the dynamic motion of the screw press and potential resulting settlement within the loose sand stratum. This combination of large loads and dynamic motion resulted in the selection of a helical pile and tieback system to support the concrete foundation. The helical pile foundation system consisted of a group of vertical helical piles installed into the shale rock and a group of inclined helical tiebacks set into the remaining portion of the clay stratum. Four load tests were conducted on the vertical helical piles in order to establish compression load capacity. The results of these load tests as reported herein, led to the addition of a limited number of tubular steel push piles in order to meet the project required Factor of Safety on the design loads. All of the helical piles, push piles and inclined helical tiebacks were successfully installed and the screw press is now installed and operational.

Jan 1, 2003

During a mineral exploration program in an environmentally sensitive area nearMount Painter in South Australia, a helicopter was used to position, construct and service drilling rigs in order to avoid the need to create new access tracks. The drilling program was designed to optimise the advantages of natural landforms in order to minimise the environmental impact of site construction and drilling activities. This minimisation of land disturbance reduced the required amount of rehabilitation measures to the extent where all impacts of the helicopter-supported programme had disappeared within 12 months of completion of work.

Jan 1, 1995

By Lex L. Udy

Properties of an explosive which itiuence its performance on rock breakage are analyzed in relation to the rock: hardness and a discussion on the interaction of an explosive with the rock during the blasting process is given. Theoretical concepts regarding ideal and non-ideal detonation are reviewed to explain how the physical and chemical factors of an explosive influence the rate of energy release and its consequence on blasting performance. While a lower velocity of detonation indicates a slowed chemical reaction it does not necessarily mean a loss in energy from the explosive. High density ammonium nitrate (HDAN) can be used effectively in the formulation of modern industrial explosives to slow the energy release rate with its attendant decrease in detonation velocity. Examples of blasting performance using custom formulated explosives with HDAN are presented.

Jan 1, 1995

By K. Lang

A case study is provided that highlights the successful use of high efficiency electrical submersible pumps (ESPs) adapted from the oil and gas industry for a large scale, open pit mine dewatering operation. In this case, the mine is Goldcorp?s Peñasquito Mine, Peñasco and Chile Colorado open pit development areas in Zacatecas, Mexico. At the time of publication (July 2012), there were 18 vertical bedrock dewatering wells producing an average flow rate of 350 liters per second (lps) from the Peñasco and Chile Colorado development areas. Average pumping rate per well was 18 lps, with a maximum of 44 lps. The depth of wells varies from 330 m to 500m, and includes both in-pit and perimeter (ex-pit) pumping centers. A network of 50 piezometers was used to monitor the response of groundwater levels to pumping. Since dewatering operations were initiated in 2007, groundwater elevations decreased overall, from approximately 1950 m above sea level (masl) to around 1625 masl, for a total of 340 m of drawdown. The pit floor elevation was approximately 1655 masl. All of the producing wells were constructed with 16-inch boreholes, completed with 10-inch diameter blank casing and louvered screen sections and equipped with ESPs. The application of ESPs has proven to be highly effective in the case of Peñasquito?s dewatering operations. Noted advantages include the following: ? Small diameter pump allows use of smaller diameter boreholes (16 inches) and casing / screens (10 inches) reducing well drilling and construction costs ? Greater application range for flow rate and total dynamic head ? Variable speed drive systems for greater energy efficiency and flow rate optimization ? Integration of downhole instrumentation into the motor and pump assembly The advantages and benefits of using high efficiency ESPs revolutionized the dewatering program at Peñasquito open pit mine as evidenced by the number of deep vertical well installations and high dewatering flow rates and total dynamic head requirements.

Feb 27, 2013

By K. Lang

The use of high-efficiency electrical submersible pumps (ESPs) for large scale, open pit mine dewatering operations provides a good example of how technology, products and services from the oil and gas industry can be adapted to the mining industry. In this case, the mine is Goldcorp?s Peñasquito in the Zacatecas state of Mexico, at the Peñasco and Chile Colorado open pit deposits. The technology, products and services are from Schlumberger artificial lift (AL) and Schlumberger industrial water services (IWS). Overview of high-efficiency ESPs This section provides a brief description of the basic components, specifications and operating capacity ranges for the ESPs compared with traditional or conventional dewatering well pumps. This information helps to establish how ESPs provide certain functional and economic advantages over conventional pumps in a mine dewatering application. A schematic of a high-efficiency ESP in an oil and gas (O&G) application is shown in Fig. 1.

Sep 1, 2013

By Vasile Murariu, William Pate, John Herbst, Dilek Alkac

"Multiphysics models are essentially first principles models capable of providing very accurate micro scale predictions. The computational requirements for Multiphysics Models are extensive, precluding their direct use for flowsheet simulations. Population balance models get their form from theory but the model parameters have to be provided from experiments. The prediction errors for the population balance models are typically significantly higher than those for the Multiphysics Models but the computational effort for Population Balance Models is typically much less than that for the Multiphysics models. The hybrid model described here takes advantage of the strengths of each of the two primary model types and minimizing the weaknesses of each. The Multiphysics Model is used to perform high accuracy "experiments" that are difficult or impossible to conduct in laboratories or plants. The results of these experiments are combined with standard laboratory or plant data to parameterize and further enhance the Population Balance portion of the hybrid model. The creation of a useful Hybrid Model is demonstrated for a MP1000 secondary crusher. The validation of the hybrid crusher model is also presented. Finally the use of the Hybrid Model is illustrated in a full comminution flowsheet simulator."

Jan 1, 2014

Use of Impact Crushing for the Enrichment of Low-Grade Colemanite Concentrates This paper presents the results of an investigation into the enrichment of -25+3 mm low grade colemanite concentrates exploiting differential breakage properties of various minerals associated within the ore sample. Boric acid production process requires concentrates containing at least 42 per cent B2O3, hence concentrates below this grade either stock piled or further treated to increase B2O3 content. The low grade concentrate is obtained as a by-product of Emet Colemanite Concentrator and the B2O3 content may vary around 37 - 38 per cent. The sample used in the experimental studies assays 37.52 per cent B2O3. In the experimental procedures the sample was crushed using a laboratory size horizontal shaft impact crusher and the products were classified into different size fractions by screening so that any improvement by size could be observed. In the tests the effects of parameters such as the revolution speed of the crusher and heat treatment was checked. Test results prove that boron contents show a tendency to increase as the particle size decreases. As a result of the experimental studies a colemanite concentrate assaying 42.13 per cent B2O3 is produced with 76.55  per cent recovery. Arsenic content is seen to change inversely proportional with the B2O3 content of the concentrate such that it drops from 1016 ppm from the as received sample to 676 ppm in the concentrate.

Sep 13, 2010

Federal regulations require the use of methane monitors on all mining machines. All machine-mounted methane monitors currently used in underground coal mines rely on catalytic heat of combustion sensors. As a comparison, although not currently approved for use on underground mining equipment, instruments with infrared sensors are evaluated in this study. Potential advantages of using infrared sensors include faster response time, long-term stability, and reduced maintenance needs. Tests conducted in the laboratory and at a full-scale model mine compare the performance of catalytic heat of combustion and infrared sensors operating under test conditions designed to simulate airflow conditions underground.

Jan 1, 2009

By Bradford NL

The Isa Mine of Mount Isa Mines Limited produces 2.6 million tonnes of silver-lead-zinc ore annually from sub level open stopes of which approximately 40% comes from the narrow Racecourse orebodies below 15 level.Geologically the stoping environment is complicated by highly fissile shale hangingwalls and below 17 level by a high stress regime.The realization that major hangingwall failures and generally poor ground conditions could lead to serious dilution problems, and ultimately production shortfalls, prompted investigations into the use of low strength explosives.

Jan 1, 1985