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The use of cemented paste backfill (CPB) is becoming increasingly more common at underground mines worldwide. Part of any CPB design includes the specification of the (typically) shotcrete barricades that retain the CPB within the stope during filling. Newmonts Tanami Operations (NTO) has started an in situ barricade stress monitoring program. The data from this program will provide a basis for comparison of several models that can be used to model the capacity of these barricades. These models vary in complexity from analytical solutions to 3D numerical models. Part of the comparison will include a discussion detailing the required material inputs and how these inputs were obtained. Analysis of this comparison will provide additional understanding on what parameters affect the ultimate capacity of a shotcrete barricade.
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Many publications are available that provide statements of best practice in terms of open pit slope risk management. However, to date none provide a risk model that demonstrates the risk reduction achieved for applying each of the risk management elements. This leaves the slope stability practitioner unable to analytically answer questions such as: ? How frequently should slopes be inspected? ? How frequently should prisms be read? ? Should a radar be acquired? If so, which one? ? How many monitoring systems to use? And many more. This paper applies the Venter and Hamman (2018a) temporal safety risk model to an open pit in West Africa. The paper demonstrates the use of the model to a small saprolite open pit and concludes with recommendations for slope instability registers to facilitate future back?analysis in terms of this model.
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Geoprofessional Business Associations (GBA) Tailings Engineer-of-Record (EOR) Task Force published a Business Brief to inform and educate Member-Firms of the ever-increasing levels of risk associated with tailings dams.
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An awareness of the rate at which water resource development took place in South Africa being supply driven, until relatively recent times, leads to an appreciation of the changing philosophy in respect of water conservation and pollution control, as well as essential amendment to principles and procedures. Reconciling water demand and supply in catchments requires concurrent consideration of available water quantity and quality. This stimulates the need for change in the way we view water uses and brings about business opportunities in the sector. The review of infrastructure designs in support of water use and mining applications for industrial and mining waste has developed and transformed along with improved technology and changes in legislation since 1994 in South Africa. A containment barrier system comprises of both filter protected drains and low permeability liners which are visible in the short term until covered. They are required to perform effectively after initial use and are often inaccessible for the operating period and subsequent service life of decades or even centuries. This paper presents a regulators perspective of commonly repeated deviation from accepted norms and standards in the engineering profession, as applied to pollution control facilities. Emphasis is placed on the standards of today with experience reflecting on the past five years of design reviews, leading to conclusions and recommendations for facility owners and practitioners. Examples of procedure, mechanisms, performance, specifications and socio-economic benefits are addressed. It is postulated that in the near future many mining and industrial developers will choose to improve containment standards of barrier systems as a component of reengineering water demands and for economic advantage while embracing contributions from ecosystem services.
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Report and appendices to the report available on the bottom of this web page. Appendices are relatively technical.
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ASDSO is a national non-profit organization serving state dam safety programs and the broader dam safety community to improve the condition and safety of dams through education and support for state dam safety programs. Largely focused on dams for flood protection, water supply, hydropower, irrigation.
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The filtering of sandy tailings from the reverse cationic flotation processes and the subsequent stacking of these tailings has shown to be a very strong trend in Brazilian iron ore mining, especially after accidents involving geotechnical structures known as tailings dams, but also due to concern of mining companies to develop a disposal technique that is more complacent with the environment and the surrounding society. In order to develop the sandy tailings filtration project, a fundamental requirement was the correct choice of filtration technology among the many existing ones. For the material object of this study, the filter with vertical discs presented itself as the most productive due to factors such as granulometry, specific surface of the material and the humidity required in the filtration product. Several exploratory and material characterization tests were carried out for this purpose. Disc filters have the principle of operation linked to the difference in atmospheric pressure and the vacuum pressure induced by pumps. The vacuum must act on the filtering screens next to the filter heads and, in order not to drop the yield, the system must be sealed hydraulically. As previously mentioned, there are basically two ways to hydraulic seal the system. The first and most common in Brazilian iron ore filtration is carried out through barometric columns and the other is using filtrate pumps installed directly in the vacuum receiver of the filtration facilities. The decision of which method to use has major implications for the design of the filtering installation and the comparison between the two conditions mentioned is the objective of the present work.
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The goal of the study considers operational approaches that would increase fines capture to reduce the amount of fines that cause formation of MFT. This study includes a review of case studies to understand fines capture rates in existing facilities, processes controlling beach fines capture, and the operational changes that may increase fines captures. A high level review of available modeling tools are used to asses if operational factors are appropriately addressed within the models.
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With the intention of trying to determine the causes of major tailings dam incidents, 221 case records have been collected. Examples are given of accidents and failures, together with some examples of effective remedial measures. This Bulletin is addressed to all those involved in the design, construction, operation and closure of tailings dams.
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The forecast of seismic hazard in mines depends on the planned mining sequence and therefore it is required to: 1. Model the changes in stresses and strains associated with future mining. 2. Transform these changes to the parameters of expected potentially damaging seismic events (location, time, size, mechanism). This modelling of expected seismicity has to be calibrated. It needs to be shown that the recorded seismic response to the mining in the past can be replicated using a numerical model. The seismic hazard calculated for future mining steps also needs to be tested against the observed seismicity after the planned mining is completed. The same mathematical framework can be used for both the calibration and the testing of seismic hazard forecasts. The area skill score (Zechar & Jordan 2008) is adopted to assess the match between the location of significant seismic events and calculated hazard maps for the past mining steps (calibration) and forecast maps for the future mining steps (testing). The 3D rotation angle (Kagan 2007) is used to compare the source mechanisms of recorded significant seismic events with the expected mechanisms for the past and future mining steps. The seismic events affecting the poor performance of the forecast both in terms of location and source mechanisms can guide possible adjustment to the input parameters of the model (e.g. orientation of in situ stress, failure criteria) and help to improve the forecasts. The suggested approach of calibrating and testing of seismic hazard forecasts is illustrated using data from Renison mine, Australia.
