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By D. Rutledge

Discrete (digital) signal processing techniques are proving to be very valuable tools for miners using the block cave method. Waveform analysis of different measured signals associated with active mining provides valuable information on production dynamics and safe operation of the mine. For example, correlation of the 3D surface displacement velocity waveform and the production output waveform reveals a remarkably predictable time-varying physical process. Studying the geometrical and temporal relationship between these two signals opens a broad window through which new management techniques become apparent. In this paper we discuss the signal processing techniques used to study these relationships, as well as the related implications for mining. This research was carried out in association with the Chevron Mining underground molybdenum mine in Questa, New Mexico. Some of these new techniques will be integrated into the decision management process at the mine and will provide insight on ore production, draw control, and safe reclamation. The science of signal processing involves the analysis and interpretation of physical processes that vary with time. Two general categories of signals1 are recognized. A continuous signal is a waveform of varying amplitude that is continuous in time (such as a sine wave). A discrete signal is a sequence of quantized values. The independent time variable and amplitude are sampled periodically such that we only know the value and shape of the waveform at the sampling frequency. Displacements measured by a Global Positioning System (GPS) receiver are an example of this. Discrete signals may be studied in the time, frequency, autocorrelation, or wavelet domains. In this paper the amount of ore extracted from the mine and the measured surface displacements are analyzed in the time domain.

Jan 1, 2008

By Sarma S. Kanchibotla

In overburden cast blasting the explosive energy is used to move a significant percentage of overburden from the high wall to the spoil pile thus reducing the amount of material to be handled by machinery. However, the obvious trade-off between the extra explosive energy in the cast blast versus reduced dragline effort is complicated by an increased risk of damage to the underlying coal. This damage may not be obvious but inevitably leads to reduced coal recovery and may negate much of the benefit sought from cast blasting.

Jan 1, 1999

By Nick D. Rose

Outline ?Background ?History of inverse-velocity for failure prediction ?Methodolog ?Case Histories ?Three case examples of predicted slopefailure to actual date of occurrence ?One case example of mitigated slope failure using inverse-velocity to forecast failure time and schedule remedial measures ?Conclusions

May 1, 2006

By Aaron S. Bradshaw, Ryan M. Coulson

The offshore wind industry in the United States is slowly emerging with the recent construction of the first offshore wind farm located off the coast of Rhode Island. The turbines at the Block Island wind farm are supported by piled jacket structures, which historically have been used for much heavier oil and gas platforms. Offshore wind turbines have unique design requirements and the axial behavior of the supporting piles under cyclic loading is important to design. Cyclic degradation along the pile shaft can affect the capacity, deformation, and stiffness performance of the foundation and of the structure as a whole. This paper proposes a strain-based approach to estimate the fatigue (or endurance) limit of a cyclically loaded pile that may be applicable to long-term service loading. The method is applied to an existing load test dataset and the analysis results appear consistent with the observed pile response. INTRODUCTION The demand for renewable energy has been increasing in recent decades and wind power has seen a dramatic increase in popularity. In Europe, as of 2017 there were 4,149 grid-connected offshore wind turbines across 11 countries (windeurope.org), many of which are supported on monopile foundations. It wasn’t until recently (2016) that the first offshore wind farm was constructed in the United States off the coast of Block Island, Rhode Island. The project included 5 piled jacket structures founded in terminal moraine deposits. Future offshore wind development along the U.S. eastern seaboard could possibly utilize jacket structures in granular foundation soils. Loads from wave, wind, and turbine rotation induce cyclic loads on the foundation that have on the order of 108 loading cycles over the service life on the structure (Schneider and Senders 2010). Turbines located along the U.S. east coast have the added risk of hurricanes. As shown in Figure 1a, the lateral loads on a jacket structure are transferred primarily as axial compressive and possibly tensile loads on the supporting piles depending on the weight of the structure. The friction along the shaft of the pile can be prone to cyclic degradation, leading to reduced pile capacity and stiffness, and increased deformations. An offshore wind turbine foundation must be designed for a variety of limit states including ultimate, serviceability, and fatigue limit states. For a jacket structure this would include an analysis of the ultimate axial pile capacity, axial stiffness, and axial deformations, all of which can be affected by cyclic loading both under extreme (i.e. storm) conditions as well as long-term service conditions. Axial pile stiffness is needed, for example, to estimate the natural frequencies of the structure as a whole and to assess dynamic and fatigue loads. The structure must be designed such that its natural frequency remains outside the loading frequencies of the waves and turbine blade passing frequencies to avoid resonance. Therefore, prediction of the axial response of the piles is important to the design of these structures.

Jan 1, 2018

By M. Karimi

Artificial neural networks (ANNs) have found their applications in the modelling of unit operations of mineral processing plants. In this research, laboratory-scale tests were conducted, using a three-inch diameter Mozley hydrocyclone. Main parameters included pressure drop at inlet, solid per cent, vortex and apex diameter were adjusted. The corrected cut size (d50c) and the flow rates of underflow and overflow were determined. Multi layers perceptron (MLP) feed forward network architectures were designed to predict the responses. The results showed a good correlation between experimental and network output, for corrected cut size and flow rates. Keywords: hydrocyclone, artificial neural network, corrected cut size, flow rates.

Jan 1, 2010

Remote sensing, in general, is the recording of light and heat from a planet's surface within a certain range of the electromagnetic spectrum. For the Earth, systems capable of this recording are the MultiSpectral Scanner (MSS) and SLAR. The former is the recording system used in satellite and will be discussed in the next section. SLAR stands for Side Looking Airborne Radar. This device sends invisible radar waves which illuminate the Earth's surface. The reflected waves are subsequently recorded as images. The system can operate through darkness and dense cloud cover, and is particularly suited for the study of geological structures at both large and small scale (Wayland 1976). Remote sensing techniques are now widely being made use of in mineral exploration, especially for those last remote 'sanctuaries' where geological data are meagre or non-existent. For places like Borneo, West Irian, the Amazon Basin etc. remote sensing, in the form of both satellite imagery and SLAR, is of considerable help, in fact more often than not the only help, to delineate geological provinces, geotectonic domains and meaningful lineaments. In the case of New Zealand, well made geological maps at scale 1:250 000 by the Geological Survey are available to the public and these provide useful preliminary grounds for the selection of target areas. However, even in this case LANDSAT imagery can be of aid as will be shown later.

Jan 1, 1977

By Murali M. Gadde

Perimeter mining is a special form of very productive partial extraction method practiced at some mines in the United States. In the Illinois Basin mines where all major coal seams have weak underclay in the immediate floor, experience shows that any long-term ground control issues will arise due to floor failures rather than instability of the coal pillar itself. While there is a significant amount of work done on floor stability associated with regular pillars, no work has been done so far on the stability of perimeter pillars. This paper reports the results of a comprehensive study that was conducted for the first time on floor stability during perimeter mining in the Illinois Basin mines. A special plate template, which mimicked a common perimeter pillar configuration was created to conduct in-situ bearing capacity tests at five mines in three states of the Basin. Additionally, because of the complex shape of pillars created in perimeter mining that defies any closed-form solution, floor bearing capacity was studied using three-dimensional nonlinear numerical modeling. Based on these in-situ and numerical studies, some guidelines are provided for perimeter pillar stability analysis.

Jan 1, 2009

By W T. Yen

Pyrrhotite crystallises as either a hexagonal or monoclinic structure, both of which can occur in ore deposits. In general, pyrrhotite is not considered as a valuable mineral unless it contains considerable amounts of other metals like nickel or copper. In fact it causes numerous problems in flotation including intensive oxygen consumption, which results in poor selectivity among sulphide minerals in the processing of complex sulphide ores. Also, because of its high sulphur content, pyrrhotite is a major contributor to environmentally detrimental sulphur dioxide (SO2) emissions from smelters. Pyrrhotite also interacts galvanically with grinding media via electrolyte species present in the flotation pulp, resulting in media corrosion. The most effective way to reject pyrrhotite is through a separation stage, which may be difficult when both types of pyrrhotite are present in the ore. In this regard depression of pyrrhotite through a flotation stage may be applied. Pyrrhotite depression by either intensive oxidation or by using sodium cyanide has been practiced. Results present in this work show that NaCN can depress pyrrhotite effectively when combined with an alkaline environment and low collector concentrations.

Jan 1, 2002

By Scott Ellenbecker

Soon New York City will have a new train station. A tunnel project is under construction to extend Line 7 to a new station that is located near the Jacob K. Javits Con-vention Center. This is also part of the Hudson Yards redevelopment project that is intended to aid redevelop-ment of the west side of Midtown Manhattan around the Long Island Railroad?s Caemmerer Railyard. The station, or ?cavern? as it?s called by those excavating it, will be the portal for that growth. In the city, public transportation means high-rise residential proper-ties will have better access to the business district, and those outside the area will have greater access to event facilities ? two factors that are critical for development investment.

Jan 3, 2010

By G S. Lane, G D. Richmond, J Dioses

This paper discusses the methods used in the design of flotation plants, including benchscale batch and locked cycle tests and pilot plant trials. Two case studies are presented, one for the Cadia Hill Gold Mine and the other for the Hellyer copper, zinc and lead plant. These case studies present different problems with widely different target grind sizes, liberation characteristics and HellyerÆs sequential flotation circuit versus CadiaÆs æsimpleÆ copper/gold flotation circuit. They have a common theme in that pyrite forms the principal floatable concentrate diluent. Hellyer ore contains finely disseminated chalcopyrite, sphalerite, galena, and tetrahedrite. The flotation plant design was based on extensive benchscale testwork (including locked cycle tests) on drill core and many months of operation of a 30 tonne per hour æpilot plantÆ, using the old Cleveland Tin Mine process plant suitably modified for the duty. The Cadia concentrator was designed on an extensive benchscale variability testwork program, approximately a dozen locked cycle tests conducted on drill core and two weeks of continuous pilot plant trials on three separate samples obtained from an adit into the orebody. The orebody is a monzonite porphyry with disseminated chalcopyrite/bornite/pyrite of very low grade (0.17 per cent Cu, 0.73 g/t Au). Methods used to establish the appropriate flotation circuits for the treatment of the Hellyer and Cadia ores, as well as the interpretation of the testwork data, are discussed in this paper. Plant performance is reviewed in the context of predicted versus operational performance.

Jan 1, 2002

By Vahid Tajdar

The behavior similarity between pile and cone penetration test, has guided the researchers to use the CPT results in prediction of piles bearing capacity. In this article, artificial neural networks have been used to study about relation between cone tip and sleeve friction strength obtained from cone penetration test and ultimate pile bearing capacity, obtained from static pile load test. Artificial neural networks "ANNS" is a form of artificial intelligence. ANN tries to dramatize the human nerves & brain system biology structure in self-structure. In this article, the results of relevant studies about the prediction of ultimate pile bearing capacity in especial area of soils are presented by use of back - propagation neural networks. The results of static pile load test up to failure on 63 piles with closed end and CPT test results in the place of construction these piles use in order to confirm and creation ANN model. Comparing predicted ultimate pile bearing capacity by utilizing ANN with the numbers which are predicted by 5 common traditional methods shows that using of artificial neural networks is a suitable method for predicted ultimate pile bearing capacity in identified area of texture of soil moreover it has a better operation in comparison with common traditional methods.

Jan 1, 2006

By F F. Pitard

The optimization of metallurgical processes requires knowledge of the heterogeneity carried by constituents of interest. The common scenario, almost an industry standard, is to rely on the engineering firm who in turn relies on favorite manufacturers of sampling equipment to provide the appropriate sampling systems in the plant to perform accurate metallurgical accounting. This sequence is flawed from the beginning to the end because everything should be based on a careful understanding of the Theory of Sampling (TOS) by the company project team and their expert who invariably would suggest various approaches and different sampling systems.The necessary progressive and iterative approach should be that the company’s project team (mining or other industries) would do its home work to have a good understanding of the geometallurgy, mineralogy and texture of the ore in each geological unit so consultants and engineers would have the best information to start with. Then a reputable sampling expert would recommend which sampling systems are needed, so the company would require engineering firms to follow pre-established, non-negotiable requirements, and finally select the sampling equipment existing on the market today that is most likely to lead to accurate and precise enough metallurgical accounting.It is the author’s experience that when this necessary progressive and iterative approach is bypassed, sampling systems installed in the plant are likely to transgress the most elementary rules of sampling correctness. Invariably the argument is that the company cannot afford correct sampling systems for metallurgical accounting as suggested in the Theory of Sampling. There is nothing that is farther from the truth when later problems will develop and inevitable reconciliation difficulties with miners and geologists become daily routine with impossible answers; as a last resource the sampling expert may be called to perform a post-mortem analysis.The progressive and iterative approach suggested in this paper should be a due diligence requirement for any bank providing a loan for an important new mining project; anything less is most likely to generate unpleasant financial losses; historical, well-known examples are referred to.CITATION:Pitard, F F, 2015. A progressive, iterative approach leading to reliable metallurgical accounting sampling systems, in Proceedings MetPlant 2015, pp 78–91 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

Airy kind of a power system is a complicated network of various electrical components, such as cables, transformers, electric machines, circuit breakers, etc. For a system to work continuously and efficiently, each of the components has to be in perfect operating condition. The failure of any of these components can cause serious interruption of the supply and may in several cases involve a lot of precious time and labor in removing and replacing the damaged equipment it may also give rise to dangerous overvoltages on the system, thereby causing a safety hazard. Any piece of electrical equipment can have two likely modes of failure. The first would be the degradation of solid insulation material due to overheating, mechanical damage or a combination of the two, In this mode of failure it is possible that If the insulation damage is not an instantaneous phenomenon (a cable damaged by severe mechanical, Stress) that a detectable leakage current will do lop prior to the faint. The fault would probably he a result of heating and deterioration of the insulation by the leakage current.

Jan 1, 1975

By James Anstey

BHP Billiton?s Cannington facility is a mining and minerals processing plant near Mt. Isa in Central Queensland, Australia, producing silver, lead and zinc. Mine ore is processed in a concentrator, which consists of grinding, flotation, thickening and filtration. Grinding is carried out in a fully autogenous (AG) mill. The mill operates in closed circuit with a pebble crusher. Throughput is approximately 380 tph. Cyclone overflow from the grinding circuit is fed into a flotation circuit for the recovery of lead, zinc and silver. Two concentrates are produced (lead and zinc), which are then thickened and filtered. The filtered concentrate is transported by road to a rail receiving station. From here the concentrate is railed to port in Townsville for shipment to the smelter. Matrikon and Engineers at BHP Billiton?s Cannington Mine have used ProcessACT to develop a flexible, nonlinear dynamic simulator for the grinding circuit to further enhance process understanding, as well to investigate various optimization strategies. An online charge volume estimator was also developed for the AG mill to aid in the understanding of overload conditions, which for the previous two months had been the primary contributor to downtime. The models were developed using a combination of first-principles modeling along with input-output dynamic responses. Examples of models used include: Morrell ?C? model for power and charge shoulder/toe angle prediction; Whiten?s mixing model for breakage and hold-up; Nageswararao cyclone model for predicting cut size; slurry recovery and water recovery. The composite model simulates system dynamics starting from the stockpile reclaim system and finishing at the feed for the flotation process. The objective was to provide a tool that assisted Cannington in understanding their Grinding Circuit and allowed them to develop and evaluate circuit optimization strategies. BHP Billiton Cannington Mine is now considering development of a Grinding Circuit Optimizer utilizing the models developed for the simulator.

Apr 1, 2005

By Ian Bruce

Tailings and water management facilities are essential and integral components of mine and mill operations. They must be managed for the long term in order to ensure that safe and environmentally responsible stewardship is achieved. Toward this end, in 1998, The Mining Association of Canada (MAC) published A Guide to the Management of Tailings Facilities, which recommended the implementation of a tailings management framework (Figure 1) to integrate environmental and safety considerations into each stage of the life cycle of a tailings facility, from initial site selection and design, through construction and operation, to eventual decommissioning and closure. By February 2000 it was becoming apparent that while mining companies were making significant progress toward implementing and documenting tailings management systems, and integrating them with overall environmental management systems, further effort was warranted in their application at the operational level. In particular, a need was identified for further guidance in preparing manuals that outline procedures for the safe operation, maintenance and surveillance (OMS) of tailings and water management facilities.

May 1, 2002

By Rudolph Emmel

THE mines operated by the South American Development Co. are located in the Zaruma mining district of southwestern Ecuador. They are near the old mining town of Zaruma, which is the only important city in the canton of the same name. The district is situated in the upper end of a valley lying between two spurs of the Cordillera, one of which may be considered the Coast Range and the other an intermediate range. The mining camp proper, known as Portovelo, and the plant are 2.4 km. south of Zaruma, on the north bank of the Amarillo River, a tributary of the Tumbes River, which flows southwestward through Peru to the Pacific. Portovelo is difficult of access; it is reached from Guayaquil by means of river steamers and muleback. Embarking at Guayaquil, the route is down the Guayas River, across the Jambeli Canal, and up the Santa Rosa River to Santa Rosa, a distance of 177 km. From Santa Rosa, the road or trail follows the Santa Rosa River, then across the summit of the Coast Range into Portovelo, a distance of 74 km.-a two-day trip on muleback. The mining property of the South American Development Co. comprises 297 lode claims and 142 placer claims. The combined lode claims cover an area, roughly rectangular in shape, 9000 m. long from north to south by 4000 m. wide; the northern edge of the rectangle is about 3000 m. north of the central plaza of Zaruma. Mineral lands in Ecuador are held by virtue of an annual tax per claim paid to the central government, no surface rights being included.

Jan 1, 1925

By H. S. Price

This report discusses the development of a mathematical model that describes the flow of methane only and methane and water in a coal bed during mining operations. Because of the complex geometry, boundary conditions and fluid properties, the model is based on a numerical solution to the equations describing flow. The goals for the development of this model and requirements to which it complies are for the most part expressly stated in Request for Proposal No. 50110752. In addition to the capabilities specified under the scope of work the model can handle an anisotropic porous medium and a source term has been added which will simulate, somewhat, the effects of desorption. This term will be pressure dependent. The effect of time on such a term is only taken care of in the change of pressure with time. This source term will have the dimensions of Mcf/day/Mcf pore volume. It will be a part of the input data to be supplied by the user and will be entered as a table of rates versus pressure. These models consider the fracture system as the main porosity. All computed results pertain to the fractures. The source term mentioned above represents the flow from the matrix porosity into the fracture. Such flow should be small compared with the flow between fractures since these models handle only one porosity structure system.

Jan 1, 2012

By P. Venter, N. Naude

"Coal mining is a thriving industry and 53% of the coal mined in South Africa is used for electricity generation. Mechanization has made coal mining more efficient, but fines generation has subsequently increased. Up to 6% of the run of mine material can report to the -200 µm fraction. Common problems associated with fines handling include dust formation, storage problems, and high moisture levels. A method to turn this material into a saleable product instead of stockpiling it can add value to a company.Briquetting is a pressure agglomeration method where loose material is compacted into a dense mass (FEECO International, 2014). The briquettes must be able to withstand rigorous handling and transport operations without disintegrating. This study aims to investigate the optimum binder and moisture conditions required to produce a mechanically strong briquette using two different binders - a PVA powder (binder A) and a starch powder (binder B).It was found that for binder A the optimum moisture level was 12% to 14%. At this moisture level the greatest compression strength gains were observed, and low amounts of fines produced in impact and abrasion tests. The minimum amount of binder added while still obtaining a strong briquette was 0.5% binder A. For binder B the optimum moisture level was also 12% and the minimum amount of Binder B to be added was found to be 1%. Briquettes that were dried outside reached their peak strength after about four days, whereas the briquettes that dried inside took about 20 days to reach their strength plateau. Hardly any degradation took place on the surface of the binder A film after exposure of 300 hours of artificial weathering. Thermogravimetric analysis confirmed that neither binder A nor binder B will add to the ash content of the coal fines, as both binders totally decompose above 530°C.Binder B yielded stronger briquettes after 15 days and also generated less fines. It is therefore superior to binder A and would be recommended for further use.Paper written on final year project work carried out in partial fulfilment of B.Eng degree in Coal Beneficiation"

Jan 1, 2015

By David C. Uhrin

Two improved methods have been developed to transfer microfilmed mine maps to suitable base maps showing surface features. The methods provide for (1) positioning and orienting maps; (2) merging adjacent maps; and (3) plotting maps at a common scale. One method produces an overlay mosaic of mine maps using an Integrated camera-processor. This photographic method shows the details of mine workings and is most useful for specific limited-area projects. In the second method, outlines of mine maps are digitized, manipulated, and plotted as overlays using a computer. This computer method can plot mine outlines and spatially index large numbers of microfilmed maps. Microfilmed mine maps used in this Bureau of Mines study are on file in the Mine Map Repository of the Eastern Field Operations Center. The base maps are U.S. Geological Survey 7.5-minute topographic maps. The demonstration area is located in the New Kensington East and West quadrangles, Pennsylvania.

Jan 1, 1977

By Michael S. Wieland

Charge malfunction problems result from rather universal damage mechanisms and are widespread throughout surface and underground delay blasting. Recent refinements in instrumentation technology reveal a range of charge performance difficulties, not just outright misfires. This report focuses on the U.S. Bureau of Mines research regarding desensitization and malfunction of delay detonators and cap-sensitive explosives, utilized in underground coal mining. Delay blasting generates tremendous shock waves and rifting forces that fracture and heave the surrounding stratum. The shock waves from charge explosions propagate outward in all directions through the coal, impacting neighboring charges with later delays. The impact phenomena have debilitating effects, causing degrees of reduced charge performance ranging from misfires or weak detonations to out-ofsequence detonations. Impaired charges react poorly. fracture less coal, and produce fumes with higher toxicity. Coal-mine, underwater, and simulator tests were conducted to m3re thoroughly understand the shock-wave and rift-compression damage mechanisms. Recently the U.S. Bureau of Mines partially resolved the malfunction problem by demonstrating the feasibility of formulating a rugged explosive, which could pass the requisite tests for certifying an underground coal-mine explosive. The charge formulation was not certified only because it lost initiation sensitivity too quickly from natural aging and had to be rebatched to finish the testing.

Jan 1, 1994