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Overview ?Oil Sands Background ?Water Use in Surface Mining ?Tailings Disposal ?Water Balance for Surface Mining ?Implications of Emerging Regulations ?Water Management Framework ?Tailings Performance Criteria (Directive 074)

May 1, 2009

By C Beal

Proper understanding and management of production drilling in sublevel cave (SLC) mines is essential for meeting production targets and for avoiding inefficiencies that could lead to costly bottlenecks. In many SLC mine management models drilling is considered a derivative activity of firing and bogging. Its scheduling is considered to be implied in a firing schedule and given an arbitrary target completion, ‘several weeks’ or ‘a month’, ahead of production firing. Like development, drilling activities are most efficient when conducted separately from other production activities. Unlike development, however, it is not apparent during planning and feasibility how far in advance of firing drilling activities ought to be conducted. This paper presents a method of defining a minimum threshold of drilled stocks above which drilling, firing and bogging operations occur most efficiently. As an example, the drilling activities, procedures, and maintenance at Glencore Xstrata’s Ernest Henry Mine are presented, and the larger scale consequences of improvements to these areas are presented to illustrate their importance in the operation of an SLC mine.CITATION:Beal, C, 2014. Understanding the role of production drilling and drilled stocks in efficient operation of a sublevel cave mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 235–242 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By Nava-Vasquez E, Torres-Torres J, Mendez-Nonell J

The ZA-27 zinc base alloy was poured into cylindrical moulds and solidified under different conditions ie normal freezing and unidirectional freezing. In addition a cylindrical ingot with rheocast material was obtained by stopping the stirring action and, at a specific solid fraction, gravity casting it into a graphite mould. It was observed that the material obtained under normal freezing conditions is likely to present both segregation and inverted pipe. In contrast, the unidirectional solidified and the rheocast cylinders showed the absence of inverted pipe. The segregation pattern was quite irregular in the rheocast ingot while such segregation was more uniform in the unidirectional solidified cylinder. By virtue of these observations, the inverted pipe formation may be ascribed to the interdendritic flow, while the irregular segregation pattern in the rheocast ingot may be attributed to an irregular distribution of the liquid and solid fraction along such a cylinder.

Jan 1, 1993

By John L. White

The vibro driver/extractor is a machine that grips to a pile and vibrates it up and down. When the vibrating pile is lowered into the ground, all soil around the pile begins to vibrate. A vibrating pile breaks the friction between the pile and the soil, thus allowing it to penetrate the ground. A vibro is usually operated by hoisting it into the air with a crane and then placing it onto the pile. The vibro has hydraulic gripping jaws that are controlled from the ground. Once the operator has successfully lowered the vibro onto the pile, the jaws are closed and locked onto the pile and operations can begin. Please see the drawing below: [ ]

Jan 1, 1990

By Charles Barnhart

This paper is a discussion of the causes of deflagration in cast blasting and a description of a project intended to demonstrate how changes in six critical parameters contribute to the deflagration chemical reaction. Control of these parameters is key to solving the nitrogen dioxide “orange smoke” problem. Preliminary results of an investigation into the development of a technology addressing the problem of atmospheric releases of nitrogen dioxide during cast blasting in surface mine operations are described. The project is funded by a $600,000 Small Business Innovative Research grant from the National Science Foundation and an $80,000 Abandoned Coal Mine Land Reclamation Program grant from the state of Wyoming. The presentation will address the measures required to control the blast chemical reaction so that it does not produce nitrogen dioxide through deflagration. Experimental blast data will be focused on a new shaped charge detonation system designed to instantaneously bring the powder column to maximum velocity of detonation (VOD), thus insuring efficient detonation of the entire colulnn.

Jan 1, 2003

By S. K. Ghosh

This paper discusses how the information on ash composition, ash-fusion temperatures, and ash-slag viscosity can be utilized to predict slagging and fouling potentials of a particular coal. A review of several empirical parameters which are commonly in use for determining such potentials is given. Also, some guideline values for interpreting the relative propensity of slagging and fouling of various types of coal are provided.

Jan 1, 1983

By Michael S. Wieland

"Toxic fumes cause fatal andnonfatal incidents in underground mining, where the working environment tends to trap the fumes, hindering the restoration of non-harmful conditions. Workers can underestimate the residual fume toxicity and return to the work site too quickly. The toxic fumes from charge explosions depend upon a number things: formulation ingredients, mixture uniformity, water resistance, hole contaminates, rock hardness, and dust interactions. Transitory hole-to-hole waves can cause partial desensitization, ruin the reaction kinetics, and worsen the fume toxicity.Traditionally the toxic fume hazard for a candidate explosive is resolved from a requisite tally of fume components. The resolution starts with the fume spectrum, a tabulation of specie concentrations, transformed to standard reference conditions and readjusted to remove the air dilution. The resultant influence, which is referred to as relative fume toxicity RFT, is deduced by a formula rule with some chosen constants and the requisite concentrations. The RFT result is normally compared to an RFT criterion that represents the worst-case (maximum) tolerable fume toxicity, as stipulated by regulations or otherwise."

Jan 1, 1997

By G Lumley

PlannersÆ optimism (or maybe commercial necessity) means that most mine plans use equipment rates that are rarely achieved (Lumley and Beckman, 2009). This lack of understanding of what equipment actually moves is causing erroneous equipment forecasts, leading to incorrect mine development plans and economic evaluations. Compounding this problem is a downward trend in actual equipment performance in some areas. Consequently, the presentation of realistic mine plans that are actually achieved in practice is not a common occurrence. However, rational, fact-based mine planning is available to those who want it. Hundreds of millions of cycles of data from open cut mining equipment has been collected from mines around the world since 1992. This unique and highly valuable databank is growing at an exponential rate and is being used by a number of our big miners to support rational and fact-based decision-making. However, neither the use nor the appreciation of the value of this data is universal. There is a challenge to everyone in the mining industry - how do you access value from it? The databank was drilled into and the results analysed for, the Australasian Mining and Metallurgical Operating Practices (AMMOP) publication (Lumley, in press). For this paper the analysis has been extended to include interpretation of trends for draglines, shovels, excavators and trucks. It investigates trends between coal and non-coal mines and across geographic areas. It is known that mining equipment performance in most sections of the industry is falling. This paper attempts to quantify the fall and provide explanations. The trends are analysed to extract the reasons behind the changes and most importantly, what can be done about it.CITATION:Lumley, G, 2012. Understanding trends in performance of open cut mining equipment, in Proceedings Project Evaluation 2012 , pp 203-224 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By D. J. Carpenter

Safe and successful mine closure represents a fundamental work element that needs to accommodate the geochemical conditions existing at the completion of the mining and ore processing effort. Given the interests in limiting costs and time associated with mine closure efforts enhanced prior understanding of the geochemical conditions likely to exist upon exhaustion of the economic reserves can provide important benefits. The purpose of this paper is to document the benefits associated with geochemical modeling and understanding how the ore formation process may impact mine closure efforts, using one ore deposit type as an example. Specifically, this paper will emphasize the geochemical processes leading to the formation of sandstone-hosted uranium roll-type deposits and how the resultant concentrations and distributions of ore and gangue phases need to be incorporated into understanding the geochemical conditions projected to exist at the end of mineral recovery efforts. The paper will describe the evolution of geochemical conditions leading to ore body formation and the geochemical effects induced by open pit mining and how these may be used to understand both the geochemical controls and constraints on residual mine water. In addition, a discussion will be provided on how these conditions may be simulated by solution equilibria and kinetic modeling to develop optimum approaches to achieve applicable closure standards. This paper will also discuss specific augmentations to existing industry standard solution equilibria and kinetic models and associated thermodynamic databases to maximize the predictive accuracy of the geochemical modeling results. The benefits of understanding the electrochemically reactive behavior of uranium and associated gangue phases and incorporating this behavior into mine closure efforts will be presented. The culmination of the benefits of the geochemical modeling will ultimately be the development of a sustainable approach to uranium mine closure that is based upon an engineered environment designed to return the ore body to stable geochemical conditions.

Feb 27, 2013

By T. Prietl

Metallurgical vessel linings are multilayered, consisting of refractory bodies, insulation materials, joints, and additional space to control for thermal expansion. A unique biaxial hot testing press (BHTP) was installed at the RHI Refractories Technology Center Leoben, Austria to enable the three-dimensional behaviour of complex vessel lining segments to be investigated under simulated service conditions. Using the BHTP, the heat up and thermo-mechanical behaviour of magnesia chromite brick lining segments with and without mortar filled joints were examined. The results obtained during the initial heat up provided validation of CFD modelling of the lining system. In addition, after the heat up and under steady state conditions, the lining behaviour during deformation-controlled compression and relaxation was examined. These analyses generated important data regarding the stiffness, joint compressibility, and brick damage of the lining segments after cyclic loading and unloading as well as the benefits of using mortar joints in the lining. These investigations were performed in collaboration with the Christian Doppler Laboratory for Secondary Metallurgy of Nonferrous Metals, University of Leoben, Austria. The BHTP has been operational since November 2004 and is providing information regarding the thermo-mechanical behaviour of different lining segments.

Jan 1, 2007

By Terri Jordan, Gregory Hempen, Thomas Keevin

Water-borne blast pressures from confined blasts were recorded as part of a submerged blasting program in Florida for channel deepening. The blasting was confined within the rock floor by stemming. Shot patterns of stemmed borings were recorded, as were two open-water shots. One hole of one shot was not confined properly, which allowed comparison of confined and a poorly confined larger charge weights per delay. The pressure data were intended to gain information on typical pressure measures from the rock removal program relative to impacts on marine organisms. Water-borne pressures from actual confined, rock-removal shots validate the hypothesis of lessened impacts to aquatic and marine biota.

Jan 1, 2007

By Paulo José Costa Couceiro Junior, Manuel Lopez Cano

In 2011, two historic outcrop rocks known as Teffé and Itapema located in the navigation channel of the Port of Santos, Brazil (Latin America’s largest port) – were excavated by drilling and blasting techniques. Sensitive structures - a passenger terminal and an 80-year old warehouse were exposed to ground vibrations generated by underwater blasting. The warehouse had existing structural problems due to a combination of factors such as the presence of an unstable soil, previous repair work, and intense seismic events generated by the daily traffic of cargo trains nearby during eight decades. Since the worsening state of the structure was attributed to ground vibration from underwater blasting, particle velocity time histories generated by underwater blasting and by passing trains were monitored. By analyzing the energy spectral density of these events using spectrograms, it was possible to observe the seismic energy levels in time and spectral domains. Since the hysteretic energy dissipation by structures is related to the duration of the seismic event and the limited dissipation capacity of the structure, one could expect damages to appear in the structure once energy levels exceeded this dissipation capacity. As the quantity of energy transmitted to the structure is proportional to the duration of the seismic event, the transmission of seismic energy to the warehouse structure over time was more significant in the case of the train-induced ground vibrations (several minutes) than those generated by the underwater blasting (few seconds). Thus, for the warehouse, train-induced ground vibrations have a larger impact on the structure rather than ground vibration generated by controlled underwater blasting techniques.

Jan 1, 2016

By Dhawan AK

On 8 July 1993, a landslide of about one million cubic metres of rock blocked the river Satluj near Sanjay Vidyut Pariyojana - Bhaba project and caused flooding into the Bhaba Power House (120 MW) resulting in suspension of power generation. The concerned authorities desired an early removal of the blockade by an underwater blasting operation into the over topping water to reduce the water level at the blockade and resume power generation in the power house. In the absence of underwater drilling, it was essential for the blasting technique to be used where no cavity to confine the explosive was required. For this reason mud capping and plaster shooting with directional throw were used and additional specially fabricated mild steel pipe charges were used under high current for an underwater trenching operation. By employing these techniques the river blockade was removed up to the required depth and on 8 September 1993 the Power House resumed the power generation.

Jan 1, 1995

By Joshua Taylor Drake

This report answers specific questions concerning underwater blasting considerations, and blasting safety. The blasting considerations discussed consist of basic blasting principles, and new variables to be accounted for. Blasting safety will include the safety of personnel and structures. The environmental considerations will also be discussed with mitigation methods. To be most effective, this document requires the reader to be familiar with key fundamentals of explosive engineering. In order for a blasting professional to benefit from this report, the following questions will be asked:

Jan 1, 2015

By Colin C. West

On August 7, 1986, Barge 45, while being towed near the mouth of the Niagara River, was swept downstream and pinned against one of the central piers of the Peace Bridge. The barge rested against the pier with 125 feet overlying the Canadian border and 50 feet overlying the American border. The tug boat which was towing the barge was lost further downstream. Fortunately, the crew escaped and were rescued with no loss of life. There was serious concern about the potential erosion effects of the river currents on the foundation of the bridge pier as caused by the flow concentrations around the barge structure. Due to the time of year, with the approaching Fall and associated worsening weather conditions, it was imperative that the barge be removed as soon as possible. Donjon Marine of New Jersey, the United States Navy's Atlantic Zone Contractor, was called on to retrieve the barge. By this time the original owner had abandoned the wreck.

Jan 1, 1987

By Sam X. Yao

The underwater concrete technology has historically evolved largely through a trial-and-error process of constructing marine works. Many outstanding examples exist of high quality concrete placed underwater. However, failures also occurred and led to excessive cost and/or schedule overruns. These failures were largely due to improper concrete mix design or improper placement. The problems may have occurred because proper underwater concrete construction techniques and experience have not been widely disseminated. This section focuses on technical issues of underwater concrete mix design, concrete production and placement, and quality control.

Jan 1, 2013

By Sam X. Yao

In construction of drilled shafts under water, placing concrete in the shafts is technically demanding and involves complex construction logistics. Past construction experience has demonstrated that high quality concrete can be placed in drilled shafts under water with a proper concrete mix and proper placement techniques. However, a significant number of failures have occurred which have resulted in excessive cost overruns and delays. These problems may have occurred because proper underwater concrete construction techniques have not been widely disseminated within the industry. This is a technical area where competent design and sound construction planning can achieve a significant reduction in both risk and cost. This paper will discuss some key technical issues in the concrete mix design, concrete production and placement for the drilled shaft construction. The paper also describes two lesson-learned case histories from drilled shaft construction projects.

Jan 1, 2013

By N. K. Davé

Water quality impacts of shallow water submersion of partially weathered and oxidized waste rock containing reactive sulphide minerals were investigated in laboratory column lysimeter studies. The waste rock investigated was highly reactive, contained oxidation reaction products from previous exposure and weathering, and had a low sulphur content of approximately 2 % S, mostly as pyrite. The submerged waste rock, though previously weathered, had high oxygen consumption, resulting in rapid depletion of dissolved oxygen in its pore water, within a shallow depth of ~2?5 cm from the surface. The surface and pore water qualities of the submerged waste rock were significantly impacted by the dissolution and release of previous-oxidation-reaction products, which contributed to their rapid acidification and having increased concentrations of dissolved SO4, Fe total and other metals: Al, Mn, Ca, Cu, Ni, Zn and Pb. Despite the high porosity and permeability of the waste rock, the diffusion controlled mass transfer from the submerged waste rock to the overlying water cover was relatively low for most ionic species. Additional surface oxidation of the sub-merged, partially weathered waste rock was on-going, but its impact on the overall surface water quality was low and masked by the dissolution and release of previous oxidation reaction products to both surface and pore water regimes.

Jan 1, 2006

By Martti Hagfors

Underwater explosions have been used as a test method for the determination of energy content of explosives for several decades. This is the only test method by which shock, gas heave and total energy values can be measured separately. The experimental data can be measured from the pressure-time curves measured by the pressure-recording unit. The shock energy is integrated from the shock peak area and the gas heave energy is calculated from the time interval between the primary shock wave front and the shock wave caused by the first bubble implosion. tb. Bubble period, tb, is the time of first bubble oscillation, the time which passes after the shock peak front to the first bubble peak. The total energy value is the sum of these two partial energies.

Jan 1, 2009

The underwater test method for the determination of energy content of explosives is a very useful method. It’s also the only one which can separate shock and gas heave energies from each other. The total energy can be determined as a sum of these partial energies. Because of this special feature, the test method can be used to develop the energy content of explosives for different purposes; the military high explosives should contain more shock energy whereas the gas heave energy is a very important feature for the blasting explosives. The goal of this study was to find out the effects of aluminium and sodium perchlorate increments to the shock, gas heave and total energy values of an emulsion explosive and detect the particle size effects of two different aluminium powders to the total and partial energies as well. Both partial energies as well as the total energy were observed to increase linearly as a function of aluminium (A-80) concentration. The fine aluminium powder (A-100) (6%) also seemed to increase the shock energy of the explosive slightly whereas the gas heave energy was observed to remain unchanged to compared to the normally aluminazed (A-80) (6%) emulsion explosive. Therefore the fine aluminium powder also increased the total energy, but only very silightly. The fine aluminium powder can probably take apart to the chemical reactions more easily during the detonation. (3%) of sodium perchlorate (NaClO4) mixed with (6%) of (A-80) aluminium powdered emulsion explosive was observed to effect to the gas heave energy content of the explosive, but only very slightly. The shock energy was observed to remain unchanged.

Jan 1, 2005