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.
Image classification is a process whereby the spectral information of an image, based on its digital numbers, attempts to classify individual pixels to a theme or specific object (e.g. vegetation, water, vehicles, people, etc.). The output is generally an image map or mosaic of pixels, each of which belong to a particular theme or identification to produce an independent overlay of the original image. This overlay can be used to provide a post analysis regarding changes that are occurring in a sequence of images or, for example, identify a potential hazard that can trigger an action for human intervention. The accuracy of image classification is based on having enough information to train a model to identify the theme or object of interest. This paper presents the results of a supervised machine learning technique whereby target objects were identified and models run to train the classification algorithm to identify changes in supernatant pond size, rates of rise, detection of inflows of water to an area and presence of mobile equipment. Training images were acquired from site-based static time-lapse cameras that have been taking images since early 2017 of different areas of a tailings storage facility in the north of Chile.
The British Columbia Technical and Research Committee on Reclamation originated in the early 1970's, in response to a demonstrated need in BC for greater government-industry communications in the area of environmental protection and reclamation associated with mining. All BC Reclamation Symposia papers from 1977 to current are available for free at the University of British Columbia library. The UBC library collections have been revised making it much easier to search key subject areas such as native species, revegetation techniques, tailings, mining best practices, environmental monitoring etc., the author, paper title, and/or year presented (all the way back to 1977).
This bulletin concentrates on the difference of approach (relative to water retention dams) necessary when considering the instrumentation for tailing dams. Sound advice is given about the importance of seepage measurements and the need for automation to provide continuous records, methods for measuring the position of the phreatic surface. The difference of approach between embankment dams and tailings dams is shown.
This bulletin provides references to publications written up until 1989 on tailings dams. It divides the references into the following categories: Tailings Sources; Deposition and Disposal Techniques; Safety and Failures; Stability of Tailings Embankments including Seismic Aspects; Material Properties and Evaluation; Legal Aspects; Site Selection and Investigation; Tailings Transportation; Drainage, Seepage and Groundwater; Decants, Water Management; Pollution Control and Environmental Aspects; Closure and Rehabilitation:Monitoring; Instrumentation; Vegetation; Reworking Existing Deposits; General.
This manual presents guidance on procedures for use in the engineering design, construction monitoring, operation, and inspection of coal refuse impoundments and embankments in the United States.
Ground motion over mine sites, while an everyday occurrence, may represent hazards that need to be identified and monitored over time. An accurate and regularly updated overview of surface movement over mining operations is therefore critical as part of an ongoing risk assessment program. By having a complete picture of ground stability, movement patterns which represent potential geotechnical hazards to safety and mine operations can be identified and tracked over time. From routine monitoring to highfrequency updates, interferometric synthetic aperture radar (InSAR) technology is increasingly being used to identify a wide range of movement patterns which may be of concern to mine operators and geotechnical engineers. Recent advances in radar image processing algorithms, combined with an increase in the number of satellite systems launched into orbit, have resulted in improvements in the ability of this technology to capture complex and rapid displacement. In particular, the ability to characterise rapid and sudden motion (metres of movement) has increased the utility of InSAR from a practical standpoint in characterising geotechnical hazards. Further exploitation of 2D monitoring approaches in capturing vertical and horizontal movement, particularly for producing displacement vectors along cross sections, can also provide additional insights into hazard characterisation. Key differences between the ability of highresolution imagery to capture complex and rapid deformation in comparison to low-resolution (but freely available) Sentinel imagery are also touched upon. This paper will focus on the practical application of InSAR technology to monitor mine sites around the world, illustrating how new processing approaches and data sources are used in the identification of geomechanical risks that are typically of greatest concern from both an operational and safety standpoint. Examples of results over an active mine site will be shared and a particular emphasis will be placed on selecting the right InSAR tool for helping geotechnical engineers best manage risk due to movement.
?Chile produces large amounts of tailings daily which must be safely disposed on the earths surface. There are a series of strategies that have been successfully used in our country to store tailings, among them are thickened and paste tailings. Paste tailings are an advantageous technique that allows for greater recovery of water while improving physical stability of the structure. Although challenges are faced worldwide when large production rates are tried to be thickened, the technique seems promising for countries like Chile where there is an ongoing water crisis. The stability of paste tailings facilities is highly influenced by water content or saturation. As consolidation occurs the tailings loses water. However, as the evaporation front takes place, the material goes from a saturated to a non-saturated state. Unsaturated paste has shown improved resistance, e.g. liquefaction resistance almost double when saturation drops below 90%. A well planned facility operation should consider the monitoring of the water content of the paste. However, this is sometimes difficult, due to the large areas that must be controlled and the danger associated with manual moisture measurements in the field. In this context, we proposed the use of hyperspectral cameras to obtain a relationship between the paste moisture content and light reflectance. This would allow to generate moisture surface map and to the use of this data to monitor for instance evaporation rates or water balance in tailings storage facilities. This article summarizes laboratory main findings and proposes a series of procedures to implement the technique in the field.
The perceived need for accurate and reliable methods of measuring suspension rheology in real time arises from the greater demands being placed on mineral processing operations. To extend mine life and reduce TSF footprint the adoption of finer grinds, higher solids concentration and high clay ores result in complex multiphase suspensions that need close monitoring to optimise thickener performance, pipeline transport and tailings deposition. Often the control of the processing or transport of these suspensions can be related to its rheology. However, due to the involved nature of rheological measurement for suspensions and the nuanced interpretation of data necessary to produce useful decisions, rheometry has only seen limited application in process monitoring. A robust unit that can measure, analyse and interpret the rheology of a process stream continuously and unattended is needed. The CSIRO has developed an online rheometer to address this problem. This paper describes the process prior to the deployment of the online rheometer to an Australian goldfield site, comparing online rheological measurement to benchmark laboratory values.
Mining facilities store process water or paste slurry. Lateral and vertical water percolation may create major problems concerning dam safety and environmental impact. Means for monitoring the saturated zone is widely used, but none concerning the unsaturated zone (vadose zone). A novel Vadose Zone Monitoring System (VMS) was developed at Ben Gurion University in Israel. VMS units include a set of advanced water and pressure sensors along with sampling ports. The units are mounted on a flexible sleeve which is installed through dedicated uncased small diameter boreholes. Through a control panel on the surface, data is transmitted via a cloud-based server directly to the clients dedicated application. Over the past decade, the VMS was successfully installed in a variety of scientific and commercial projects on water infiltration and contaminant transport from land surface to the groundwater in a variety of geological and hydrological setups. Recently, fertilizers producer in Israel (ICL), installed several VMS stations under phosphogypsum waste lagoons for monitoring the potential leaks from the bottom of lagoons to the subsurface, and one system in in an earthen dam for monitoring its safety status. The case study deals with contamination that was discovered in the aquifer. Continuous monitoring of water percolation beneath the ponds indicated that the levels of water percolation and pollution potential from these ponds are relatively low and therefore environmentally safe. These findings were accepted by the environmental authorities and the client wrote: "The VMS already had an important use, in proving the authorities that the contamination is from another source and not from our cell. We couldn't have done it any other way". Implementing of the VMS systems at the above case and other cases produced real time information which has proved to be critical for maintaining long term safe operation of tailing sites.