scholarly journals Geotechnical Risk Classification for Underground Mines / Klasyfikacja Poziomu Zagrożenia Geotechnicznego W Kopalniach Podziemnych

2015 ◽  
Vol 60 (1) ◽  
pp. 51-61
Author(s):  
Ritesh Kumar Mishra ◽  
Mikael Rinne

Abstract Underground mining activities are prone to major hazards largely owing to geotechnical reasons. Mining combined with the confined working space and uncertain geotechnical data leads to hazards having the potential of catastrophic consequences. These incidents have the potential of causing multiple fatalities and large financial damages. Use of formal risk assessment in the past has demonstrated an important role in the prediction and prevention of accidents in risk prone industries such as petroleum, nuclear and aviation. This paper proposes a classification system for underground mining operations based on their geotechnical risk levels. The classification is done based on the type of mining method employed and the rock mass in which it is carried out. Mining methods have been classified in groups which offer similar geotechnical risk. The rock mass classification has been proposed based on bulk rock mass properties which are collected as part of the routine mine planning. This classification has been subdivided for various stages of mine planning to suit the extent of available data. Alpha-numeric coding has been proposed to identify a mining operation based on the competency of rock and risk of geotechnical failures. This alpha numeric coding has been further extended to identify mining activity under ‘Geotechnical Hazard Potential (GHP)’. GHP has been proposed to be used as a preliminary tool of risk assessment and risk ranking for a mining activity. The aim of such classification is to be used as a guideline for the justification of a formal geotechnical risk assessment.

Author(s):  
R. Mishra ◽  
L. Uotinen ◽  
M. Rinne

SYNOPSIS Underground mining gives rise to geotechnical hazards. A formal geotechnical risk assessment can help to forecast and mitigate these hazards. Frequentist probability methods can be used when the hazard does not have many variables and a lot of data is available. However, often there is not enough data for probability distributions, such as in the case of new projects. The risk assessment is often subjective and qualitative, based on expert judgement. The purpose of this research is to present the use of Bayesian networks (BNs) as an alternative to existing risk assessment methods in underground mines by combining expert knowledge with data as it becomes available. Roof fall frequency forecasting using parameter learning is demonstrated with 1141 sets of roof fall data across 12 coal mines in the USA. The prediction is nearly identical for individual mines, but when multiple mines are evaluated it is difficult to find a single best fit distribution for annual roof fall frequency. The BN approach with TNormal distribution was twice as likely to fit the observed data compared to the Poisson distribution assumed in the past. A hybrid approach using BN combining multiple probability distribution curves from historical data to predict annual roof fall is proposed. The BN models can account for variability for multiple parameters without increasing the complexity of the calculation. BNs can work with varying amounts of data, which makes them a good tool for real-time risk assessment in mines. Keywords: Bayesian network; expert opinion models; geotechnical risk; incident forecasting; parameter learning; roof fall risk.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Alexander H. Frank ◽  
Robert van Geldern ◽  
Anssi Myrttinen ◽  
Martin Zimmer ◽  
Johannes A. C. Barth ◽  
...  

AbstractThe relevance of CO2 emissions from geological sources to the atmospheric carbon budget is becoming increasingly recognized. Although geogenic gas migration along faults and in volcanic zones is generally well studied, short-term dynamics of diffusive geogenic CO2 emissions are mostly unknown. While geogenic CO2 is considered a challenging threat for underground mining operations, mines provide an extraordinary opportunity to observe geogenic degassing and dynamics close to its source. Stable carbon isotope monitoring of CO2 allows partitioning geogenic from anthropogenic contributions. High temporal-resolution enables the recognition of temporal and interdependent dynamics, easily missed by discrete sampling. Here, data is presented from an active underground salt mine in central Germany, collected on-site utilizing a field-deployed laser isotope spectrometer. Throughout the 34-day measurement period, total CO2 concentrations varied between 805 ppmV (5th percentile) and 1370 ppmV (95th percentile). With a 400-ppm atmospheric background concentration, an isotope mixing model allows the separation of geogenic (16–27%) from highly dynamic anthropogenic combustion-related contributions (21–54%). The geogenic fraction is inversely correlated to established CO2 concentrations that were driven by anthropogenic CO2 emissions within the mine. The described approach is applicable to other environments, including different types of underground mines, natural caves, and soils.


2020 ◽  
Vol 150 ◽  
pp. 03024
Author(s):  
Y. Zerradi ◽  
A. Lahmili ◽  
M. Souissi

In underground mines, excavating disturb the initial equilibrium state of the rock mass, and therefore require selection of a support in order to control the movement of rocks, avoid landslide and work safely. Thus, the progress of mining operations in the ST2 mineralization, in the eastern zone of the Bouazzer mine, is disrupted because of stability problems. On the basis of field observations and analyzes of core drill, the geological and structural study, carried out in this area, has shown the existence of three types of facies: altered and cracked diorite, cobaltiferous mineralization which is in contact with serpentinites. In fact, the empirical methods such as Barton, Bieniawski and the recommendations of the AFTES have qualified the rock mass as poor, furthermore they proposed as kind of supports: steel arches, shotcrete and rock-bolts. Numerical simulation by the finite element method proved to be very complex due to existence of several types of discontinuities (faults, shistosities and joints).These discontinuities are natural fractures that delimit various shapes and sizes of wedges, which can become detached from the roof or siding of the excavation and collapse under their own weight. Although the empirical methods cited above provide supports for each facies, however, this support is expensive and difficult to implement in practice because it must cover the entire surface of the excavation and thus not allowing to detect stable blocks that do not require a support. For this it was essential to carry out an analysis of wedges to better locate unstable blocks. The treatment of fracturing data has highlighted the presence of five sets of discontinuities of which three sets are principals and the other two are minor joints. Then, while taking into account the geometrical, mechanical data of the discontinuities as well as the geometrical data of the excavation, we were able to detect the shape and the size of the unstable blocks and the sets of discontinuities delimiting them and which favor their sliding and tilting. Thus, we calculated the number of anchor bolts needed to stabilize these blocks in order to ensure an acceptable safety factor. This study shows clearly how a wedge analysis of the rock mass can guide and optimize the support work.


Author(s):  
Y.A. Sari ◽  
M. Kumral

SYNOPSIS Underground mining operations tend to have higher operating costs than surface mines. When metal prices decrease, profitability is jeopardized due to the high costs. Therefore, mining management harnesses new practices that increase operational efficiency. One way to manage this challenge is to invest in new mine planning practices. Stope layout optimization as a part of underground mine planning aims to identify a portion of the orebody in the form of production volumes (stopes) to maximize profit under roadway and stope dimension constraints. In this paper we propose a novel approach based on identifying ore-rich areas of the deposit and prioritizing their extraction through an iterative heuristic clustering approach. The proposed approach is compared with and validated by an exact method through a small mining example. The heuristics produced nearly identical results in a very short time. Finally, a case study was carried out using a larger data-set. The cluster-based iterative approach generated near-optimal stope layouts in a computationally effective manner. Keywords: underground mining, iterative optimization, stope layout planning, sublevel stoping.


SEG Discovery ◽  
2019 ◽  
pp. 16-27
Author(s):  
Ed Holloway ◽  
Scott Cowie

Editor’s note: The Geology and Mining series, edited by Dan Wood and Jeffrey Hedenquist, is designed to introduce early-career professionals and students to a variety of topics in mineral exploration, development, and mining, in order to provide insight into the many ways in which geoscientists contribute to the mineral industry. Abstract Mine planning is the process that determines the way in which an ore deposit will be mined over the life of a mining operation. It necessarily draws on everything that planning engineers believe will determine the ultimate success of the proposed mine and uses as its foundation all of the geology-related data on the deposit. It is both a strategic and a tactical process that first considers a longer-term horizon based on strategic considerations, followed by more detailed shorter-term planning processes, in this order; the latter are the result of tactical considerations. This structured process may also be referred to as integrated mine planning, and it is driven by a broader corporate strategy or set of objectives. As such, it is much more than the mining engineering section of the mine development process. It has to include inputs from all related disciplines, by combining all of the measured properties of the deposit with mining-associated parameters. This results in the planning process incorporating a significant number of interrelated parameters. If these parameters are not used diligently and accurately or are not well aligned, or if the underlying data are deficient in either quantity or quality, the project or operation is unlikely to achieve its potential, by virtue of failures in the planning process. Best-practice integrated planning incorporates relevant inputs from all mining-related fields: geology, geotechnical, geochemical, hydrogeological, hydrology, mining operations, minerals processing, marketing of product, waste management, tailings, environmental, social science, mine closure, etc. It includes all interfaces in the business-value driver model, from exploration drill holes to the mine closure plan. The planning process cannot be completed successfully by mining engineers working in isolation from professionals in other key disciplines. Because geology provides the foundation on which the mine plan is built, the quality and accuracy of the geologic data provided to planning teams by exploration geoscientists is crucial.


2014 ◽  
Vol 2014 ◽  
pp. 1-20 ◽  
Author(s):  
Chika Yinka-Banjo ◽  
Isaac O. Osunmakinde ◽  
Antoine Bagula

Underground mining operations are carried out in hazardous environments. To prevent disasters from occurring, as often as they do in underground mines, and to prevent safety routine checkers from disasters during safety inspection checks, multirobots are suggested to do the job of safety inspection rather than human beings and single robots. Multirobots are preferred because the inspection task will be done in the minimum amount of time. This paper proposes a cooperative behaviour for a multirobot system (MRS) to achieve a preentry safety inspection in underground terrains. A hybrid QLACS swarm intelligent model based on Q-Learning (QL) and the Ant Colony System (ACS) was proposed to achieve this cooperative behaviour in MRS. The intelligent model was developed by harnessing the strengths of both QL and ACS algorithms. The ACS optimizes the routes used for each robot while the QL algorithm enhances the cooperation between the autonomous robots. A description of a communicating variation within the QLACS model for cooperative behavioural purposes is presented. The performance of the algorithms in terms of without communication, with communication, computation time, path costs, and the number of robots used was evaluated by using a simulation approach. Simulation results show achieved cooperative behaviour between robots.


Author(s):  
S. B. Ozhigina ◽  
D. V. Mozer ◽  
D. S Ozhigin ◽  
S. G. Ozhigin ◽  
O. G. Bessimbayeva ◽  
...  

In the Karaganda coal basin, mines are located in close proximity to each other and to the city of Karaganda and ongoing mining operations are accompanied by a dangerous process of settling the earth's surface and monitoring are essential for the region's econ-omy. Underground mining leads to the formation of voids in the rock mass, which cause displacement of the earth surface. This paper demonstrates an innovative use of the integrated approach for monitoring on the example of Karaganda coal basin, which includes estimation of the rock mass displacement using leveling profile lines and satellite radar interferometry. It is proved that satellite radar interferometry provides reliable results of surface subsidence measurements in mining areas and can be used for con-sidered sort of monitoring.


2019 ◽  
Vol 1 (1) ◽  
pp. 35-46
Author(s):  
Jimmy Bob Suroto ◽  
Ramdhan Rabbani ◽  
Anas Abdul Latif ◽  
Presentia Biserva Aesh

The development of the Toguraci Underground Mine was begun in 2011 with the ore production started in 2012. The amount of water continued to increase in the Underground Mine at the beginning of 2014 which became problem that effected the activities of mining. The increase of hot water Toguraci underground mining effected to the safety for workers who are exposed to hot water, ventilation problems and equipment that are submerged in hot water. Tuguraci mine has two dewatering systems, namely dewatering systems on the surface and dewatering systems in underground mines. The handling of surface water comes from pumping underground to surface where water discharge is around 400 L / s with the temperatures ranging from 70°C while water treatment in underground mines includes decreasing water heading levels and pumping water from underground mines to the surface. The increase water entering heading development and stoping can be overcome by changing the surface dewatering system by using water cooling, while underground mining is done by changing the pipeline from the polypipe to the steel pipe and to reduce water entering the mining front is doned by drill holes for installing submersible pumps and replacing Oddesse pump to the Schlumberger pump which is more resistant to high temperature hot water, as long as mining operations take place 48 borehole drilling has been done with 11 borehole flowrate below 5 l / s and 37 borehole with flow rate above 5 l / s, and a water drop of around 77 meters


2021 ◽  
Vol 250 ◽  
pp. 542-552
Author(s):  
Boris Zuev

The research purpose is to develop a methodology that increases the reliability of reproduction and research on models made of equivalent materials of complex nonlinear processes of deformation and destruction of structured rock masses under the influence of underground mining operations to provide a more accurate prediction of the occurrence of dangerous phenomena and assessment of their consequences. New approaches to similarity criterion based on the fundamental laws of thermodynamics; new types of equivalent materials that meet these criteria; systems for the formation of various initial and boundary conditions regulated by specially developed computer programs; new technical means for more reliable determination of stresses in models; new methods for solving inverse geomechanical problems in the absence of the necessary initial field data have been developed. Using the developed methodology, a number of complex nonlinear problems have been solved related to estimates of the oscillatory nature of changes in the bearing pressure during dynamic roof collapse processes; ranges of changes in the frequency of processes during deformation and destruction of rock mass elements, ranges of changes in their accelerations; parameters of shifts with a violation of the continuity of the rock mass under the influence of mining: secant cracks, delaminations, gaping voids, accounting for which is necessary to assess the danger of the formation of continuous water supply canals in the water-protection layer.


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