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By Martin Langenderfer, Catherine Johnson, Alexander Douglas

Mine haul roads degrade rapidly due to extreme loads on suboptimal construction materials. Unmanned aerial vehicles (UAV) are suited to quantify large-area road-network conditions, such as surface roughness, defects and grade to optimize remediation of poor conditions and reduce overall costs. Mine haul roads present unique challenges, such as material type and edge characteristics, to automatic road detection that often fails, requiring manual road input. This research work proposes a new method using the road center determined by the principal curve of a haul truck’s path. Analysis grids were created from this center line. A dense point cloud from UAV photogrammetry was generated and multiple linear regression analysis was conducted on each individual grid. The root-mean-square error in each grid indicates the surface roughness, and the change of slope between grids indicates the road grade inconsistencies. This method was applied to 26 road sections, and the results were validated by images taken from the truck operator’s vantage point. Critical defects were identified including excessive pothole formation, corrugation, depressions retaining water, and narrowing of travel lane. The results demonstrate this is a valid method of road identification and quantification of road defects at a mine site.

Apr 1, 2024

By R. M. Cox

The ground forces generated by a properly installed and tensioned mine roof truss assembly can provide permanent mine roof support, even in severe ground conditions, either by direct suspension of the rock loads within the potential failure zone above the mine opening or indirect reinforcement of the natural rock arch that tends to form within the immediate mine roof. Notable advancements in mine roof truss support systems hardware and design technology have occurred since the introduction of the in situ mine roof truss concept for permanent mine roof support in 1966. The systematic installation of mine roof truss support systems has proven to be a very effective method of mine roof control room and pillar mines under a wide variety of ground conditions, even in areas otherwise considered unmineable because of severe roof control problems. Properly designed mine roof truss systems have also been used for permanent support of mine slopes and haulage tunnels.

Jan 1, 2002

By M. Oliverio

The Cigar Lake uranium deposit was discovered in 1981 at the south western end of Waterbury Lake, approximately 660 km north of Saskatoon in the province of Saskatchewan (see Figure 1). It is the largest undeveloped high grade uranium deposit in the world. It contains proven and probable reserves of more than 226 million pounds U3O8 at an average grade of 20.7%. The world average grade is less than 1% U3O8. [ ] The ore body is located about 450 m below surface at the interface between sandstone above and basement rock below (see Figure 2). The sandstone is fractured rock and saturated with water. This makes water inflow a real hazard at the mine. In fact there have already been two significant mine inflow events. The first of these occurred in October 2006 and resulted in the flooding of the mine. The second occurred in August, 2008 during mine recovery activities.

Jan 1, 2011

By Jr. Raleigh

As part vi the development of the Coal Quality Expert (CQRN) --a computer program capable of predicting the impacts of coal quality on power plant performance, costs, and emissions control--several nationally important coals are being characterized to augment the coal quality database associated with the software. The project is sponsored by the U.S. Department of Energy and the Electric Power Research Institute (EPRI) under the Clean coal Technology Program. Since 1989, CQ Inc. (a subsidiary of EPRI) has characterized seven bituminous coals from Alabama, Illinois, Kentucky and Oklahoma and six sub-bituminous coals from the Powder River Basin (PRB) in Montana and Wyoming. Coals from the PRB region--being burned more frequently in Midwestern and southern power plants to reduce emissions of sulfur oxide compounds--can sometimes contain significant concentrations of potentially toxic elements. Although no limits were imposed on air toxics emissions from fossil-fuel fired utilities by the Clean Air Act Amendments of 1990, future regulations may be implemented at the conclusion of Federally-mandated emissions studies. One possible result is that any increased utilization of coals, including those from the PRB, may depend on the potential for removing toxic trace elements prior to combustion.

Jan 1, 1993

By S. A. Abdel Sabour

Conventional methods for selecting a production plan for an open pit mine is based on the assumption that ore grades throughout mine life as well as market variables are known with certainty. Another important issue that is also being ignored in the conventional procedure is the value of management flexibility to revise operating policy with time according to the arrival of new information. Based on this oversimplification of reality, an optimum mine plan that is thought to be maximizing net present value (NPV) of the project is selected. Given the multiple sources of risk affecting the estimated NPV, there is a high probability that the actual value will be different from that estimated. This could mislead decision making process regarding selecting an optimum mine plan. This paper proposes a multi-criteria ranking system for selection between alternative mine designs under both geological and market uncertainties. The system is based on integrating multiple market and geological uncertainties as well as the operating flexibility to revise the ultimate pit limits using a Monte Carlo-based real options valuation (ROV) model. To compare the methods, the article applies the proposed system, along with the conventional NPV-based method, to rank possible mine designs for a copper and a gold mine. It has been found that, considering multiple risk analysis measures while integrating uncertainty and operating flexibility results in selecting a mine design that is different from that selected by the conventional method.

Jan 1, 2009

By D. D. Runnells, G. A. Doyle

The quality of water in mine pit lakes depends in part on the physical limnology, including such factors as thermal and chemical stratification, turnover and the development of anoxic conditions with depth. Limnologic data collected from four existing pit lakes in Montana and Saskatchewan indicate that pit lakes develop a thermocline (temperature stratification) in the upper 10 to 30 m (33 to 100 ft) of the water column. Two of the pit lakes, 26- and 55-m (85and 180 ft) deep, undergo seasonal turnover of the entire water column, whereas two deeper pit lakes, 110- and 240-m (360- to 790 ft) deep, undergo seasonal turnover of only the upper portion of the water column. In the deeper lakes, seasonal mixing does not extend through the entire water column, and a distinct chemocline develops with depth.

Jan 1, 1998

By W. I. Enderlin, P. O. Jackson, J. A. Glissmeyer, K. B. Olsen

A reliable estimate of radon emissions to the environment from underground uranium mines was obtained through measurements of radon in ventilation air at 24 mines and from estimates of radon release from other mine sources. The total production of U308 from the mines sampled represents about 63% of the total U.S. production from underground mines (1978 statistics). Wide variation in the radon emission rate per unit of production was found from mine to mine. Using the total radon emitted and U308 produced by all mines sampled, an average of 26.7 Ci of radon was emitted per ton of U309 produced. The investigation includes a brief study of the sources of variation of the emission rates. A statistically significant relationship was found between the measured radon release rate and the cumulative ore production at several mines.

Jan 1, 1981

By J. Darlington, A. K. SenGupta

Water-swellable layered silicates, namely, the smectite clays can remove suspended materials (called herein as debris) and metal ions from aqueous streams. The present study shows that the flocculating and metal extracting abilities of smectite clay-based flocculants can be enhanced when these clays are used in conjunction with a specific anionic polymer. Such performance enhancement is attributed to the following: i) the clay-dispersing ability of the polymeric additive, that would translate into an increase in the clay-surface area available for the attachment of the debris particles onto the clay particles; ii) the possibility of dispersant-to-coagulant transition of the polymer during the later instants of the treatment process, as a result of reduction in solvency of the wastewater for the polymer due to the release of cationic species from the clay-based flocculant solids; iii) metal-complexing ability and adsorption properties of the polymer.

Jan 1, 2002

By Jeff Poe

When a takeup weight is offset to the side of a conveyor, a wire rope is commonly routed from the takeup weight through a series of sheaves to the takeup carriage. The friction developed from a series of wire rope sheaves can effect the actual belt tension at the make up carriage. Through real-mime testing the actual tension on a makeup carriage was recorded with data acquisition using an internally strain-gauged turnbuckle. The wire rope used to transfer the makeup weight to the makeup carriage was routed through a series of lubricated bronzed bushed sheaves. The tension on the makeup carriage was found to be as much as 26% higher than the weight of the makeup due to the friction in the sheaves. A detailed discussion of the testing and results will be made.

Jan 1, 2000

By Malte J. M. Gurgel, Axel Preusse

The planning, construction, and monitoring of underground storage facilities is a key factor in meeting upcoming challenges as part of the energy transition from fossil fuels to renewables. Therefore, the many years of knowledge and expertise in ground control gained from coal mining are highly valuable for new mining and storage operations. For such applications, our previous work examined cavity registration, combining structure from motion and LiDAR through a case study in a former lead ore mine. Building on this, the results of this recent case study are discussed regarding the possible application in sites for nuclear waste disposal in Germany including a view on the situation in the United States. Photogrammetric methods are particularly suitable as part of long-term monitoring, which relies on both precise survey results and a large variety of detailed visualization. In order to gain a better understanding of the resulting application potential for holistic monitoring, both existing repositories sites in Germany and ones yet to be found are examined. This search and selection process for high-level nuclear waste disposal is studied in detail together with rules resulting from the (German) mining law, regulations, and other guidelines. Hereby, key requirements of photogrammetric products like oriented images, point clouds, and three-dimensional (3- D) models are identified for different case studies. The findings on accuracy and integrity of the generated models are not only of interest for future repository sites or underground pumped storage power plants, but also offers various possibilities for underground mining of coal and other commodities.

Jul 1, 2023

The inquiry into the explosion at the Moura No. 2 Mine in August 1994 recommended -?Emergency procedures should be exercised at each mine on a systematic basis, the minimum requirement being on an annual basis for each mine.? (Windridge et al. 1996). In December 1996 the ?Approved Standard for the Conduct of Emergency Procedures Exercises? was published and has been subsequently revised (Queensland Department of Mines and Energy Safety and Health Division 1999). This document provided guidelines for conducting mine site emergency exercises as well as the requirement for a test of state-wide emergency response by holding a Level 1 Mine Emergency Exercise at one mine on an annual basis. From 1998 to date (January 2008) ten Level 1 Mine Emergency Exercises have been held in Queensland, Australia. This paper discusses each of the exercises conducted to date as well as the logistics, scenario preparation, planning and organising required to conduct emergency exercises at this level.

Jan 1, 2009

By D. Bogh

Wound rotor motors are used in difficult mining applications where there is a need to start high inertia, hard starting loads while limiting inrush current They are recognized as robust and simple to control. This paper will cover the performance, specification, and important issues to be considered when applying medium voltage wound rotor motors in mining applications. Medium voltage grinding, crusher, and conveyor applications will be discussed. Specifically covered are motor efficiency, speed range, and rotor control. Crane motors often have wound rotor construction, but their load cycle and ratings are outside the scope of this paper.

Jan 1, 2011

By K. Sasaki

Diffusion phenomena in mine airways are important to trace gas and dust introduced into mine ventilation flows. Authors have carried out tracer gas measurements to check mine ventilation using concentration-time curves measured in mine airways, however dispersion mechanism to enhance effective diffusion have not been cleared. A numerical model using discrete tracer points dosed into tube flow has been presented to simulate their movements in consideration of turbulent velocity profile and fluctuation. Numerical simulations have been carried out to predict distributions of dosed points in tube flows with turbulent velocity profile, turbulent intensity profile and Reynolds stress. The numerical simulation results show that a combination of turbulent velocity profile and fluctuation creates extremely large dispersion of points in longitudinal direction and concentration curve with long tail was observed. This dispersion by velocity profile and fluctuation contributes large effective diffusion coefficient compared with original diffusion coefficient dominating in uniform velocity fields. Furthermore, the effect of Reynolds stress on the concentration-time curves is discussed.

Jan 1, 2009

By K. G. Correia

The replacement of the dry mining method at Guajú Mine by the dredging method was a means of ensuring its feasibility by maintaining the production levels. Dry mining increased the cost of the deposit with the distance and presented a limited mined volume, while the decreasing grade of the deposit led to a production drop. With the new methodology, there was a considerable reduction in unit cost of the mine and an increase in the production level of a deposit with low heavy minerals content.

Jan 1, 2005

By H. Wagner

Recently a detailed study ?Minerals Planning Policies and Supply Practices in Europe? has been completed. The study, conducted on behalf of DG Enterprise, demonstrated that there are very few written down national minerals policies within European Union. Mineral policy elements are dispersed in many different documents and acts. The paper discusses the essential elements of minerals policies; particularly importance is placed in issues related to planning (land use planning, mineral development, etc.). A number of examples of successful and less successful mineral planning policy approaches are presented in other to support the idea of importance of comprehensive mineral policy. The main sources of information were the country reports of 26 European countries that are appendix of the study. We conclude that comprehensive written mineral policy that incorporates essential elements is crucial in order to achieve secure minerals supply.

Jan 1, 2007

By S. Ersayin, I. Iwasaki

Application of a magnetic field was shown to be effective in controlling iron losses in pilot-scale cationic silica flotation in the processing of magnetic taconite concentrates. The design of a magnetic field distribution device and batch flotation test results using a 1.42m3 (50 cu. ft.) WEMCO cell are reported. Major losses of iron units in froth products were in the -25µm (500 mesh) fraction, and the application of a magnetic field decreased the flotation of fine magnetite, thereby improving the selectivity of separation. The “as received” sample was sufficiently magnetized and no further benefit was gained by magnetizing treatment. Selectivity was somewhat adversely affected by demagnetizing the sample, though its effect was minimal due to the magnetic field. The device is simple in construction, low cost and may be installed readily in existing equipment.

Jan 1, 2002

By A. J. Getz

The paper reviews the status of the major precious metals projects in Australia, Papua New Guinea, Indonesia, the Philippines, and New Zealand. The projects may be at the stage of exploration, development, operation, or expansion. The paper covers project location, reserves, method of resource exploitation, anticipated production, and other unique conditions.

Jan 1, 1990

By Theophilus Mensah, Kwame Awuah-Offei

Engineers face significant challenges when determining what geometry provides the most profitable and safe stope for extraction. Several techniques and optimization algorithms have been developed in recent years, but most fail to find optimal solutions because they are heuristic or LP-based without efficient geometric constraints. This paper presents a two-dimensional binary linear programming (BLP) model for determining the optimal combination of blocks in a stope that maximizes the economic value of the layout of stopes for a sublevel deposit. The work draws from Queyranne and Wolsey’s (2017 & 2018) formulations of tight constraints for bounded up/down times in production planning problems to formulate novel and efficient geometric constraints along with geotechnical and grade constraints for the BLP stope layout optimization problem. Results from the model indicate that it is possible to formulate efficient shape constraints in LP-based approaches. The model used for the numerical example contained 144 valuable blocks out of 774 blocks, which translates into an economic value of $53.21M. The BLP model selected 60 valuable blocks and 13 waste blocks that met all constraints translating into a maximum economic value of $34.4M in 1.83 hours within a gap tolerance of 0.00%.

Jun 25, 2023

By E. Tulcanaza

M.S. Azun I do not at all agree with the basic points of the author's conclusion. The use of lognormal or normal model to respond to the attribute distribution function should be carefully questioned. If fitting a distribution function of regionalized variables is the main purpose, one may employ one of certain well-known families of distributions, such as Tukey's lambda functions. For instance, the distribution function of gold assay values studied by Krige (Krige, 1978) may fit the lognormal model well, but one should not exclude that the basic idea of using the distribution function of observed data is to have insight of the physical mechanism that gives rise to the regionalized variables. In Applied Geostatistics, there are many examples considering only lognormal or normal model for the distribution function of geostatistical data even if the observed distribution function has more than one mode. Of course, using lognormal or normal model always brings easy computation for the statistical properties of attribute under investigation. Still, I object to adopting any of those models without having any "statistical inference." As seen from the author's paper, lognormal and normal model produce the same average grade (0.746% copper) and almost the same sample variance. Therefore, which model explains the probabilistic behavior of ore deposit is always an important question that should be replied by the geostatistician using not the common sense but the statistical and probabilistic methods. For kriging procedures, such as linear kriging, one should describe either second order stationary properties or bivariate properties of regionalized variables. Second order properties, such as correlogram function or semivariogram function, are the inputs of the so-called kriging equations. Selecting one of any useable models for the observed second order properties, such as spherical model, is not easy since the models are not based on the correlations structure of the regionalized variables. How those models being used in Applied Geostatistics can be distinguished is another important problem. One may develop many fitting models to respond to the observed second order properties of regionalized variables. However, I suggest that the model should be based on the probabilistic behavior of geologic process. The author used spherical model for copper, wolfram, and silver grades from isotropic sector (Fig. 2, 4, 3b) and exponential model for silver grades obtained along raises in isotropic sector (Fig. 3a). It seems that those semivariograms given in Fig. 3b for isotropic sector and Fig. 4 may be described by the random model implying that regionalized variables do belong to renewal process (Azun, 1983). If I knew the total number of data points used in estimation, I may prove that my conclusion is correct. Recalling the test for the first order sample correlogram value, the test procedure is introduced such that the independence is rejected if [ ] where Za/2 is the a/2 percentile of standard normal random variable and N is the total number of samples used in estimation (Azun, 1983). For the other observed semivariogram functions I suggest the author might try to use the so-called "Markovian model" describing not only the correlation structure of regionalized variables, but also the physical mechanism that produces the regionalized variables. The Markovian model for correlogram function is, [ ] The Markovian model for the other second order properties of ReV are also derived. T ve B, in the above equation, show, for example, structural change and mineralizational variation in a considered deposit, respectively (Azun, 1983). In selecting any model, it is not easy to search for the "best" response to the observed second order properties of ReV's. The Markovian model, based on a theoretical understanding of underlying mechanism, gives more information about the occurrence of regionalized variables and respond to all properties. Random model and the so-called hole effect structure can be easily defined as a special form of the Markovian model (Azun, 1983). An estimation of any second order properties of regionalized variables may be computed through (N-1) lag. However, the dependency between the regionalized variables may be deemed to have "died out" after the so-called stationarity width (range). In practice, the estimation is carried out through 25% of the total number samples available. Therefore, the large fluctuations around the zero level and variance for correlogram or covariogram function and semi-variogram function, respectively, cannot be observed. Since the number of pairs involved in the estimation of higher second order properties is small, the estimation variance at those lags is large. There is no need to show higher order estimated second order properties. After using one of any kriging procedure for block estimation, the distribution function of average grades has the same mean as the drilling sample grades but

Jan 3, 1985

By Cory Dippold, Michael Mett, Jérôme Steinkühler, Kristi Latimer

For decades, tunnels of all types have been a significant part of our infrastructure. In particular, water tunnels carry millions of gallons of fresh water every day to major metropolitan areas and surrounding communities. As a critical piece of public health infrastructure, it is important to inspect the condition of these tunnels regularly to ensure reliable and continuous operation. A specific challenge with water infrastructure is that it’s often difficult or impossible to shut down the system for long periods of time to perform the needed inspections. The latest method of tunnel condition assessment is the use of hybrid reality 3-D scan data. Photogrammetric and LiDAR based 3-D data ensure a reliable and objective view of tunnel conditions. The data can be used to support a detailed digital inspection including the compilation of databases that consist of a wide variety of deficiencies such as cracks and spalls within the structure. Mott MacDonald, a design engineer company worked closely with Dibit, used a 360-degree scanning system to collect high-resolution photogrammetric and LiDAR data on a recent project involving a water tunnel. The allows for full 360-degree coverage of the tunnel surface including a water covered invert. It operates at walking speed and ensures a fast and reliable data acquisition which can reduce the time of tunnel shutdowns. Several allocated inspection weeks can reduce to few days, with the final work product being a higher quality and more complete deliverable than traditional inspection methods would have provided. The true-color 3D-model has a photo resolution of 1 × 1 mm (0.039 × 0.039 inches) which makes cracks visible with a width of down to 0.3 mm (0.011 inches). The assessment of water tunnels, its technical challenges and the results of the 3D-tunnel inspection case study are illustrated and described in this publication.

Dec 1, 2022