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By R Mann, R Prasad, S Vink, V Nanjappa

The level of salinity that various aquatic organisms can tolerate without incurring any adverse effects is dependent on several environmental and evolutionary factors. These factors include the relative concentrations of different types of dissolved salts in the water that makes up their habitat, the regimes to which organisms are exposed to waters of differing salinity levels (including naturally derived variations), the degree to which an organismÆs life history stages have adapted to salinity, an organismÆs ability or behaviour to avoid adverse levels of salinity and an organismÆs capacity for osmoregulation.Release of saline water into rivers of the Fitzroy catchment has created concern about the impact on aquatic organisms. Not only is salinity itself a stressor on organisms but different ionic compositions will moderate the effects. Ecotoxicology experiments were conducted using artificial saline water based on mine water chemistry using sensitive macroinvertebrates collected from the catchment, as well as a range of laboratory organisms in accordance with the ANZECC and ARMCANZ (2000) guidelines. The 95 per cent ecosystem protection value calculated from species sensitivity distribution derived from the commercial tests was estimated to be ~2.0 mS/cm. For the protection of 99 per cent of the species the salinity has to be reduced by more than 50 per cent to 0.91 mS/cm. The electrical conductivity (EC) values, derived by commercial testing and species sensitivity distribution in this study suggests that salinity contaminant trigger values previously developed using a referential approach for protection of aquatic ecosystems from saline mine water releases in the Fitzroy may be conservative.CITATION:Vink, S, Mann, R, Nanjappa, V and Prasad, R, 2013. Determining the impacts of salinity on freshwater organisms, in Proceedings Water in Mining 2013 , pp 149-154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By E. Heikkinen, J. Suikkanen, T. Siren, J. Valli, M. Hakala

Diametrically faced borehole breakout observations are a fairly good indication of magnitude of the secondary stresses acting perpendicular to the borehole. In cases of low in situ stresses, where borehole breakouts are not observed naturally, it is possible to increase the prevailing stress state around the borehole by increasing the rock temperature. When the temperature is increased sufficiently, thermally induced borehole breakouts will occur. By implementing the temperature increase in boreholes located at excavated tunnels, it is also possible to study the effect of the near-field stresses caused by the excavation. The near-field stress state changes as a function of borehole depth, thus increasing the information available from experiment. To study the feasibility of this proposed low cost method, a Borehole Thermal Spalling (BTS) experiment was executed in ONKALO Underground Rock Characterization Facility, in Western Finland in 2014. The first borehole pilot test with the method was conducted in ONKALO at the POSE niche in already at May 2010, with the second pilot test following in August 2010 at Äspö HRL. The major objective of the experiments was to define the trend of the maximum in situ stress component, while also providing knowledge of the in situ spalling strength of the ONKALO rock mass. The stress state in ONKALO is nearly isotropic in horizontal layer, causing problems for the use of more traditional stress measurement methods. With boreholes heated over long interval, the weakest rock parts are observed to fail, thus providing statistical confidence. For these reasons, continuous test sections have an advantage in ONKALO, compared to spatially limited stress measurement methods such as overcoring and hydraulic fracturing. The BTS experiment is conducted in 9 meter deep vertical boreholes located at the POSE niche, situated -345 m depth below the ground surface. The boreholes used within the BTS experiment are located in migmatitic granite, in an experiment area where the surrounding stress state and the rock strength are fairly well known. The prior knowledge of the stresses is favourable for the experiment, as it requires careful planning and iterations to determine the appropriate heating power domain. Too low heating power will not be sufficient to cause borehole breakout, while too high heating power causes breakout in all directions thus making determination of stress direction hard or impossible. The initial state of the borehole and induced borehole breakouts will be monitored using acoustic televiewer logging (ABI) and optical borehole logging (OBI) imaging techniques. Fracture mechanics modelling is used in planning of the experiment, also in back-analysis to link the observed breakout angle to stress state. Both the pilot test in 2010 and BTS test in 2014 resulted in similar borehole breakout direction. The results are in line with so called EDZ & VT1 stress interpretation, revealed the maximum horizontal component bearing the magnitude of 21.5 MPa, with the trend of 166°.

Jan 1, 2015

By K. C. Corin, M. S. Manono

The mining and mineral concentration of Cu-Ni-PGM sulfide ores in South Africa occurs in semiarid regions. The scarcity and availability of water resources in these regions has become one of the biggest challenges facing mineral concentrators.S Owing to this challenge, concentrators have to find ways through which they can manage and control their water usage. Recycling and re-use of process water in mineral concentrators has therefore become common practice. This practice is beneficial in that it reduces reliance on municipal water, harnesses compliance to stringent environmental regulations on water usage, and it also offers a better response to the Sustainable Development Goals. This could however be somewhat concerning to the operator as recirculated water often has higher concentrations of ions compared to fresh or potable water. The unintended change in the process water quality may potentially affect critical aspects of flotation such as the stability of the froth. This has led to the need to find those process water ions that have the greatest impact on froth stability. Thus, this paper investigates the effect of various ions common in process water of a typical Cu-Ni-PGM concentrator on froth stability. Bubble size, water recoveries, foam height, and dynamic froth stability in both twophase and three-phase flotation systems are used as proxies for froth stability. Findings of this study are deemed crucial towards the development of a process water management protocol in sulfidic Cu-Ni- PGM ore concentrators. Keywords: Bubble diameter, electrolytes, flotation, froth stability, water quality

Jan 1, 2020

By J. D. Bosman, L. J. Gardner

"The Bushveld Complex is a large layered igneous intrusion, located in the northern parts of the Republic of South Africa. The complex hosts the largest known reserves of Platinum Group Metals in the world. On the western limb of the complex, mining of the Merensky economic horizon and UG2 chromitite layer has been conducted for many years by several mining companies, including Impala Platinum Limited. Over the past decade, Impala has planned a new generation of greenfield vertical shafts, commencing with comprehensive geological and geotechnical studies. As part of the geotechnical studies, numerous tests have been conducted to quantify the mechanical properties of the various near-reef rock types. These tests include point load tests conducted in the field, as well as uni-axial compressive strength, triaxial compressive strength, and Brazilian disc tensile strength tests conducted in specialist laboratories. The authors have compiled an extensive database containing a large number of tests for different rock types, ranging from felsic Anorthosite to mafic Pegmatoid. The database was analysed to quantify the mechanical properties and values for Mohr Coulomb and Hoek Brown failure criteria for each rock type typically exposed by mining. The paper will provide a data set of rock mechanical properties typically used in numerical modelling and other design processes. Using the significant number of tests available, data describing the variability of the various parameters will be included."

Jan 1, 2015

By L. Chunpongtong

ABSTRACT The mining limit in oil sands is regulated by the ratio of total mining volume (ore, interburden, and overburden) one has to mine per volume of bitumen in place (TV/BIP). This paper presents a mathematical solution for creating the most economical pit outline where the TV/BIP ratio upper limit is 12, by combining mining economic theory and the Lerchs-Grossmann (LG) algorithm.

Jan 1, 2014

By L. Chunpongtong

The mining limit in oil sands is regulated by the ratio of total mining volume (ore, interburden, and overburden) one has to mine per volume of bitumen in place (TV/BIP). This paper presents a mathematical solution for creating the most economical pit outline where the TV/BIP ratio upper limit is 12, by combining mining economic theory and the Lerchs-Grossmann (LG) algorithm.

Jan 1, 2014

By J. M. Mutmansky, Y. J. Wang, H. L. Hartman

Procedures for determining the operating point that results when a fan is connected to a mine and placed in operation have been a source of confusion for decades. A variety of techniques have been proposed, often to the detriment of the practicing ventilation engineer trying to apply the techniques to the many mine/fan matching problems encountered in the engineering of mine ventilation systems. This paper proposes some different assumptions and definitions that simplify the problems in determining the operating point. As a result, a set of procedures is provided for determining the operating point of a mine/fan system when the outlet areas of the mine and fan are known. To simplify the development of procedures for determining the operating point for a mine/fan combination, the authors suggest that the mine pressures be redefined and then used in such a manner that the conservation of energy is ensured. This provides the basis for the recommendation that the fan operating point be determined using the fan total pressure and the system total pressure characteristics. This procedure can be applied to fans in the blower, booster, and exhaust positions equally well, and to both single-fan and multiple-fan networks. Another advantage is that the method is applicable to fans with or without an evase.

Jan 1, 1986

By R. E. Ray

As coal reserves at shallow depths continue to be exhausted, a number of US coal companies are developing seams previously considered too deep to mine economically. Because of increased cover load, mines operating in deeper seams face unique ground control problems. In addition, the volume of methane gas in coal beds increases with depth, and ventilation requirements are much more stringent for deep mines than for shallower mines. When the longwall mining method is wed at great depths, ventilation, ground control, and operational considerations all influence the design of longwall panels. This paper examines these influences, particularly ventilation and operational considerations, on the feasibility of two-, three-, and four-entry longwall development panels in Jim Walter Resources' four deep mines.

Jan 1, 1988

By R. E. Ray

As coal reserves at shallow depths continue to be exhausted, a number of U.S. coal mining companies are beginning to develop coal seams previously thought to be coo deep to mine economically. Because of increased cover load, mines operating in deeper seams face unique ground control problems. In addition, the volume of methane gas contained in coal beds increases with depth, and ventilation requirements are much more stringent for deep underground coal mines than for shallower mines. When the longwall mining method is used at great depths, ventilation, ground control, and operational considerations must all be addressed in the design of longwall panels. This paper examines the influence of these factors, particularly ventilation and operational considerations, upon the feasibility of two, three, and four-entry longwall development panels in Jim Walter Resources' four deep mines.

Jan 1, 1986

By M A. Tuck

Air blasts or wind blasts as they are termed in underground coal mining, occur in a number of types of underground mining where a void develops and the overlying or adjacent rock fails rapidly to allow the development of a high pressure air pulse. The effects of air blast vary widely from very low consequence to high consequence events causing multiple fatalities as occurred at North Parkes mine. The aim of this paper is to examine the phenomena of air blasts and the underlying parameters which determine the severity of the air blast event. A basic model under development is then detailed. The aim of the model is to determine the magnitude of the pressure pulse(s) developed during an air blast event. This, combined with a transient ventilation network analysis model will enable the airflows and associated pressure drops to be determined and allow the pressure pulse around the mine to be evaluated. The overall aim is to allow mining engineers and mine ventilation engineers to undertake a risk assessment of air blasts at individual mine sites, allowing working parameters to be changed to eliminate or reduce air blasts, or engineering controls to be developed to reduce the effects of air blasts.CITATION:Tuck, M A, 2013. Determining the pressure pulse for an air blast, in Proceedings The Australian Mine Ventilation Conference , pp 103-106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Stephen Chung, Graham Mustoe, Joe Haid

In an open cast coal mining operation, a 305 m (1000 ft) long by 49 m (160 ft) thick overburden cast blast can produce more than a million cubic yards of broken muck that needs to be removed before the coal recovery process can start. In the Powder River Basin of Wyoming, it is common to see 30 to 40 percent of the overburden cast to a spoil that does not require rehandling with heavy equipment. Therefore, the higher the percent cast, the better the cast blast is rated. However, depending on the shape of the muck profile, there is often 20 to 30 percent of the muck standing in front of the high-wall. This portion of muck would require a number of dozers to push down to the dragline pad level. From the mine operator point of view, it is believed that for a given muck profile, there should be an efficient dozer pushing method such that a dragline pad can be developed in the shortest time. As a tool for analyzing this dynamic problem, a 2-D discrete element model, i-PushTM, has been developed to simulate a dozer pushing operation. This mechanistic model takes into account the dozer blade geometry, the dozer operating procedure (e.g. cut-depth, blade fill distance, forward and reverse speeds at specific slope angles), material density and cohesion. To demonstrate how i-PushTM can be used to help determine the most productive push routine, this paper presents three dozer push methods to compare the effectiveness of pushing at 3:1, 4:1 and 5:1 push angles.

Jan 1, 2006

By Jürgen F. Brune, Alex C. Smith, William D. Monaghan

One of the predominant causes of fires in underground coal mines is flame cutting and welding. These fires can lead to major events such as the explosion that occurred on January 22, 2003 in an airshaft being constructed at the McElroy mine. Six contractors were inside the shaft at the time of the explosion and the explosion fatally injured three and seriously injured three [MSHA 2003]. Understanding the root causes of these fires and explosions will help prevent these types of events from occurring in the future. Fires and explosions require fuel, oxygen and an ignition source (heat). These three items are referred to as a fire triangle. The control of these three items in flame cutting and welding operations is required to prevent fires and or explosions. United States Department of Labor, Mine Safety and Health Administration (MSHA) Reports of Investigation (ROI), MSHA Mine Accident, Injury, and Illness Reports, and the MSHA Mining Industry Accident, Injuries Employment, and Production Data Base were analyzed and interviews and observations with mine workers and welders were conducted to determine the root causes of coal mine fires and explosions caused by flame cutting and welding operations. This paper will discuss the root causes and potential means to reduce the number of fires and resulting fatalities and injuries caused by or due to flame cutting and welding.

By Robert Vinson

This article examines the spatial variability of dust concentrations within a coal miner?s breathing zone and the impact of sampling location at the cap lamp, nose, and lapel. Tests were conducted in the National Institute for Safety and Health Pittsburgh Research Laboratory full-scale, continuous miner gallery using three prototype personal dust monitors (PDM). The dust masses detected by the PDMs were used to calculate the percentage difference of dust mass between the cap lamp and the nose and between the lapel and the nose. The calculated percentage differences of the masses ranged from plus 12% to minus 25%. Breathing zone tests were also conducted in four underground coal mines using the torso of a mannequin to simulate a miner. Coal mine dust was sampled with multi-cyclone sampling cans mounted directly in front of the mannequin near the cap lamp, nose, and lapel. These four coal mine tests found that the spatial variability of dust levels and imprecision of the current personal sampler is a greater influence than the sampler location within the breathing zone. However, a one-sample t-test of this data did find that the overall mean value of the cap lamp/nose ratio was not significantly different than 1 (p-value = 0.21). However, when applied to the overall mean value of the lapel/nose ratio there was a significant difference from 1 (p-value < .0001). This finding is important because the lapel has always been the sampling location for coal mine dust samples. But these results suggest that the cap location is slightly more indicative of what is breathed through the nose area.

Jan 1, 2007

The spatial distribution of copper grades at the Mansa Mina project is highly variable due to the presence of high grade copper/silver/arsenic breccia bodies. Copper grades within the breccia bodies tend to average about 4.5% copper while grades in the surrounding stockwork average about 1.0%. The breccia is known to occur in the vicinity of significant controlling structures, however, the outline and therefore the thickness of the bodies are far from regular. Due to the high grade of these bodies a significant proportion of the value of the project is derived from the breccia tonnages. The irregularity in the outlines/thickness translates into an uncertainty in the breccia tonnage and therefore in the value of the project. Acknowledging the economic importance of the breccia bodies and the risk associated with the breccia tonnage uncertainty, significant additional drilling has been proposed to both understand the spatial distribution of the breccias and reduce project risk. The costs associated with this additional drilling are not inconsequential; thus, a reasonable question is ‘what value is derived from this additional drilling’? To obtain an answer to this important question, a simulation approach is applied. First the deposit is simulated using the existing drilling and the uncertainty in the resource is defined. Next the proposed drilling program is simulated and the simulated data are added to the existing data. Using this expanded data set a second simulation of the deposit is created and once again the uncertainty in the resource is defined. Using this approach, the reduction in the uncertainty in the resource can be determined. To convert this reduction in uncertainty (or reduction in risk) in the stated resource into a dollar value, a method of defining the increase in the project rate of return necessary to account for risk is presented. Using the two different rates of return, the difference in project NPV and hence the value of additional drilling is determined.

Jan 1, 2003

By Steven B. Van Kouteren

Value added is a loosely used qualifier in the industrial minerals industry. What exactly does it mean? What does it take to make a value-added product? More importantly, how does a company maintain the value added to its products? Most people agree that value-added means the value of a mineral minus the cost to produce it. This is misleading, though, because producing value-added products does not necessarily guarantee the profitability of the products. In some cases, firms that make value-added products are not very profitable. It is important not only to understand how to make a value-added product but also how competitive forces in the market can erode the value added. Therefore, when looking at value-added opportunities, producers must understand how to obtain the value added and how to maintain that value. Four major factors limit a company&apos;s ability to add value to its products. This paper examines these factors. It uses the ground calcium carbonate and mica industries as examples.

Jan 1, 1990

By Howard L. Hartman

There is reason to believe that ventilation systems so far devised for use with continuous mining machines fall far short of success. This is vividly demonstrated to anyone who has observed in a continuous miner section the localized ignitions of pockets of gas and the generation of dense clouds of dust by the cutting head of the machine. The alarming frequency with which major ignitions and disasters continue to occur in modern mechanical mining and the rise in incidence of pneumoconiosis serve as reminders that our ventilation systems are far from achieving the ultimate in providing protection from either short-term explosions or long- term dust diseases, both of which take lives. Human safety is the main concern in ventilation. But in this day of high-priced labor, let us not forget human comfort, either, for this is a major factor in motivation toward high productivity. The failure or inadequacy of most mine ventilation systems in providing the kind of working conditions at the face that are conducive to productive as well as safe operation is an indictment of our environ- mental control program in mining generally.

Jan 3, 1962

By S Sabanov

Determining ventilation system model inputs from the field test work has been produced in the working oil shale mine which has been in production since the early 1970s. At this mine room-and-pillar with drill-and-blast methods are used. The mine has a complicated ventilation system to supply fresh air for the eight mining production areas on the radius of about 12&#160;km. The main purpose of the experimental test works was to obtain data for estimation of an optimum cross-section area for a new ventilation shaft. Experimental test works included measurements of air volume and fan pressure using five different modes of intake air through the ventilation shafts system. Measurements of airway friction factors were obtained during the ventilation surveys to determine characteristic friction factors for the intake airway. The results of the measurements will be used for further air flow simulation processes required for design of new additional ventilation shafts in the oil shale mine. Results of the study can be useful in estimation of frictional pressure drop in oil shale mine conditions.CITATION:Sabanov, S, 2017. Determining ventilation system model inputs from field test work in the oil shale mine, in Proceedings Australian Mine Vent Conference 2017, pp 47–50 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By S. C. O?Brien

This paper develops the procedure for simulating the special locked-cycle Work Index laboratory test using the kinetic parameters obtained by conducting standard size-mass balance (SMB) grinding tests and presents the results for three materials - quartz, a taconite iron ore and a bituminous coal. It was found that the WI could be determined by simulation; however, if a material breaks abnormally, a full description of its abnormal breakage is necessary. It was also found that the sensitivity of the WI test procedure to the sieving process and the estimating of the 80% passing size of the sieve undersize is sufficient to question the practice of quoting a WI to two or more decimal places. Finally, if a material grinds abnormally in the Work Index mill, then the WI test should not be conducted.

Jan 1, 1987

By Arpit Parikh

"Ground Water or Pore water pressure development in Sandy Soil formation is Critical situation in foundation analysis and design.Moreover it become severe while associated with higher liquefaction probability in river bank areas. It is difficult to find cost optimized solution for liquefaction mitigation under limited budget allocated for the project. Here in these research paper the attempt has been made to have clear picture of liquefaction by using various techniques and field tests. And its mitigation by suitable foundation type. In Bangladesh, On Bank of River Meghana, Power plant structures are proposed. The particular site is full of fine sand having partial silt throughout from EGL to 55 m depth. Hence in addition to Conventional Boring / Drilling operations, CPLT, SCPT, SCHT and PMT had been performed to arrive deterministic effect of liquefaction. By use of Geologismiki software and some excel based programs developed which indicates that Certainly liquefaction occurs under the event of earthquake. By Checking past records of Bangladesh we found, there are small magnitude earthquakes are inevitable and frequent. Hence fourth to overcome the bad effect of liquefaction, the deep pile foundation -Driven Pre Cast Solid Square Pile of 400 mm dia. had been suggested for various types of power plant structures. Which densify the soil and ground will improve in resisting liquefaction.1. INTRODUCTIONA Detailed Geotechnical/Foundation design Analysis had been done to arrive at optimum foundation design solution in highly probable liquefaction zone of Silty Fine Sand near Dhaka City of Bangladesh for proposed 750 MW Cyclic Power Plant. Hence about 24 no. of (Borehole) Boring and Drilling up to depth of 55 m from existing ground level has been carried out. Additionally, 09 nos. of Static Cone Penetration Test (SCPT), 02 Nos. of Dynamic Cone Penetration Test (DCPT), 02 Nos. of Pressure meter test (PMT), 02 nos. of Cyclic Plate load test (CPLT) of suitable capacity with 06 nos. of Seismic Cross Hole Test (SCHT) in boreholes had been carried out. The purpose of PMT and SCHT was to have clear idea about the Seismic behavior - knowhow of site. According to Basic principles of Soil Mechanics and foundation design, it is proved that PMT & SCHT are dynamic test. These tests stimulate field condition of occurrences of earthquake. In later stages of analysis, it is found that site have high probability of liquefaction through use of Geologismiki – Liquefaction Analysis Software. Author of these research paper also felt earthquake vibrations – strong aftershocks during site study where Epicenter of the earthquake was in Myanmar during month of august 2016."

Jan 1, 2017

By K. Wangerud, B. S. Caruso

A water balance model with deterministic and stochastic components was developed and used for the Gilt Edge Mine Superfund Site, South Dakota, to evaluate risks of contaminated runoff discharging to surface waters based on assumed water treatment plant (WTP) rates for different remedial alternatives. The objectives of the modeling were to use a stochastic approach for analysis of precipitation based on historic records, and for probabilistic estimation of annual and monthly runoff from primary disturbed/mining activity areas that currently requires, or will need, treatment at the WTP, water storage and changes in a major pit, and risk of contaminated water bypass of the WTP to a downstream drainage. Subareas/source areas generating contaminated runoff requiring treatment were delineated. A simple water balance model was used based on precipitation inputs and evapotranspiration and groundwater losses. Annual and monthly precipitation records for Lead, South Dakota were used to estimate precipitation at the mine site. A lognormal distribution was estimated for monthly precipitation. The stochastic software package/Excel add-in “@Risk” was used to generate random monthly precipitation values using a Monte Carlo method based on the distributions. The average annual and monthly distribution of pan and lake evaporation, and groundwater losses were also estimated for the site. Stochastic outputs from the model for the end of each month and year included contaminated runoff requiring treatment, water storage in mine pits and the risk of WTP bypass given different assumed WTP rates. The probability of the time required to dewater the pits was also modeled.

Jan 1, 2002