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Ground control and mining in permafrost (including a bibliography)
Published in Hans Kristian Olsen, Lida Lorentzen, Ole Rendal, Mining in the Arctic, 2020
One of the most critical steps in the design of any underground mine is the choice of the mining method(s). In this choice a variety of factors come into play, including: the size, shape, attitude, and grade of the mineral deposit; the provision of support that will be necessary; and the costs for personnel, equipment, supplies, energy, and transportation that will be required in order to sustain the operation. In the past, it was not uncommon to find examples of labour-intensive, highly-selective, methods being used for the exploitation of rich deposits. Today, however, because of increasing costs of production, such methods have been largely replaced by lower-cost, bulk methods of mining. Throughout the world there has been a drive towards the implementation of advanced mechanization, automation, and teleoperation, in underground mining methods. The economic “drivers” behind this have been drastically-reduced prices for mineral commodities together with the availability and costs of highly-skilled labour.
Incorporating grade uncertainty into sublevel stope sequencing
Published in Christoph Mueller, Winfred Assibey-Bonsu, Ernest Baafi, Christoph Dauber, Chris Doran, Marek Jerzy Jaszczuk, Oleg Nagovitsyn, Mining Goes Digital, 2019
Sublevel stope sequencing problem is the long-term planning for sublevel stoping underground mining technique. Conventional stope sequencing approach focuses on ordering of the stope extraction sequence such that mine stability and production requirement constraints will be respected and the profit will be maximized. The expected revenue from a block is calculated from the block tonnage and grade. This approach assumes the ideal condition where the stope average grades are accurately known. In reality, grade information is obtained through estimation or simulation of sparse drill hole samples. Therefore, the estimated/simulated grades deviate from the actual grades. Underground mining has high development and operational costs. Thus, when the plan is made based on the estimated/simulated grades, important loss may occur if the deviation is high. Grade uncertainty can be incorporated into stope sequence planning to minimize this kind of loss. In this paper, a strategy for sublevel stope sequencing that accounts for grade uncertainty is proposed.
Uranium Enrichment, Nuclear Fuels, and Fuel Cycles
Published in Robert E. Masterson, Nuclear Engineering Fundamentals, 2017
When the ore deposits are deeper, underground mining is generally used, and this involves the construction of access shafts and mining tunnels. In any event, the uranium content of the ore is measured by measuring the radioactivity that it releases (see Chapter 6). Sometimes, the radiation detectors that are used to determine the uranium content are calibrated to detect the radiation emitted from the by-products of the uranium ore rather than the uranium itself. Large bodies of uranium are extracted with open cut mining, which is similar to the strip mining techniques that are used to mine large deposits of coal in the United States and Australia. In this case, the uranium mine is essentially a large open pit. An example of one of these mines is shown in the lower right-hand corner of Figures 10.26 and 10.27b.
Optimal junction localization minimizing maximum miners’ evacuation distance in underground mining network
Published in Mining Technology, 2023
Zhixuan Shao, Maximilien Meyrieux, Mustafa Kumral
Underground mining is challenging due to the stability issues, ground control, seismicity, safety concerns, and the complexity of the mining processes (e.g. development, blasting, mucking, crushing, hauling, and ventilation). During underground mining operations, it is possible to expose to a range of hazards that may lead to injury, fatality, or illness. These hazards may comprise but are not limited to: (1) explosions; (2) fires; (3) slips and falls; (4) unguarded machinery; (5) rock and harmful gas outbursts from earth. Each year, underground mining accidents result in fatal death and injuries of labourers (Lotfian and Najafi 2019). Furthermore, an accident, a consequence of the poor risk management of the company, causes heavy financial losses and the deterioration of the organization's reputation. According to Bugnosen (2006), mine employers are obliged to take necessary steps to eliminate or minimize the potential risk and prepare preventative emergency response strategies for reasonably foreseeable disasters. In underground mine design, one of the key aspects could be a satisfactory localization plan for the emergency junction point to which an evacuation shaft, escapeway, or a decline ramp will attach in the context of the workspace evacuation, through which the labourers with severe injuries are able to reach the outside of the mine to receive the advanced medical care. This junction point could be a shaft station used for multiple objectives.
Integrated optimisation of stope boundary and access layout for underground mining operations
Published in Mining Technology, 2019
Jie Hou, Chaoshui Xu, Peter Alan Dowd, Guoqing Li
The orebody block model is the fundamental input for optimisation. The mineralisation is delineated by geological interpretation and data from drill holes; the total volume is sub-divided into equal-sized blocks. The block size is a function of the scale on which the data are measured (drilling grid, other sampling configurations) and blocks are populated by estimated values of grades and other characteristics (e.g. geometallurgical and geotechnical variables). When economic and financial factors are incorporated, the block model is converted to an economic block model and the deposit can then be divided into valuable ore blocks and valueless waste blocks. Compared with open-pit operations, underground mining is more selective as mining can target ore blocks by access development while waste blocks may be left unmined. Ore dilution in this case only occurs largely when there is a mismatch between orebody and stope geometries.
Time-dependent rheological behaviour of cemented backfill mixture
Published in International Journal of Mining, Reclamation and Environment, 2018
X. J. Deng, B. Klein, J. X. Zhang, D. Hallbom, B. de Wit
The process of mining involves selectively recovering economically valuable minerals from material in the earth’s crust known as ore [1]. Underground mining methods allow deposits located relatively deep in the earth’s crust to be extracted and these methods result in the creation of underground voids. These voids can create serious environmental challenges, and to remedy potential problems, they are expected to be filled with waste materials by a process known as backfilling technology [2,3]. A growing number of underground mines now use cemented backfill technology for filling excavated stopes, and they are located in mining regions all over the world, such as Australia, Canada and China [4–7]. Cemented backfill mixture (CBM) consists of a mixture of waste materials such as tailings, binders such as cement and water [8,9]. Typically the solids percentage of CBM is approximately 60–80% by weight (wt.%), and the binder content ranges from 3 to 7% by weight of total solids depending on the required strength and the costs of CBM production [10,11]. This technology takes CBM to mined out areas to fill the void and support surrounding rocks which reduces the likelihood of damage caused by the movement of overburden. In addition, the resource recovery rate can be improved by implementing cemented backfill mining technology. Furthermore, the process significantly reduces the amount of waste material disposed on surface and subsequently reduces environmental impact [12–16].