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By John J. Sammarco

The mining industry has the highest average annual fatality rate among major U.S. industries. To address this, the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory (PRL), is conducting major research programs to reduce the hazard exposure of miners. One of the recently concluded programs at PRL developed the enabling technology for remote-controlled mining. An application involves the manual process of extracting and hauling coal where operators, in the tight confines of a mine, can be struck or caught by mobile machinery. The approach to remedy this problem uses a guidance system on the continuous haulage equipment so that it follows the continuous mining machine that extracts coal. This, in essence, involves sensor-based docking of the machines. Sensors functioning in the hostile mine environment of dust, methane gas, and water play the key role. Computer analysis of the mining machine's movements and empirical machine characterizations established operating requirements and spatial limitations to ensure proper loading of coal into the haulage equipment. These data served in the selection of a guidance sensor. Technologies such as scanning laser systems and ultrasonic sensors have frequently been used in other applications, but were found unacceptable. However, a near-infrared sensor employing active targets met the requirements. The sensor has a nominal 75b conical field of view and a range from 0.1 to 18.0 m. For the single-target mode, nominal range accuracy was 4.3% at a distance of 3.65 m. Correction algorithms were generated, which reduced the error to 0.6%. Airborne dust testing showed less than an additional0.8% accuracy (worst case) degradation at dust levels up to 15 mg/m3. Using four targets, the nominal range accuracy was 0.4% without correction algorithms. Analysis of dynamic testing of a continuous miner and haulage showed that accuracy was maintained and total target loss did not occur. A guidance system for the haulage system to follow the mining machine does not exist commercially. Such a system can reduce fatalities, injuries, and exposure to dust and noise.

Jan 11, 1998

By William Hissem

The topics in the title line of this article are desirable and applicable to entire industries that exist outside the realm of the ISEE’s readership. But the issues I will discuss herein are specific to those who drill, blast, and excavate rock as part of their business. Civil and site construction projects, mines, and quarries specifically comprise the group who will benefit from this discussion.

Jan 1, 2014

By S. J. Lötter, J. T. Nel, W. Purcell

"SynopsisGlow discharge optical emission spectroscopy (GD-OES) is an analytical technique used in the analysis of solid, conducting materials. Though primarily of interest as a depth profiling technique on samples with varying layers of both conducting and non-conducting materials, it is also capable of rapid bulk analysis of homogenous, solid samples. GD-OES combines the advantages of ICP-OES (wide detection range, speed, and lack of interferences) with the solid sampling of XRF techniques. This allows the analyst to not only quantify the elemental composition of a sample, but to evaluate it in terms of homogeneity with depth, a field in which auger electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS) have traditionally been the primary techniques. Although GD-OES does not replace these useful techniques, it does offer various advantages over them, making it an excellent complementary analytical tool.In GD-OES analysis, a low-pressure glow discharge plasma is generated with the sample material acting as a cathode, accelerating the cations in the plasma towards the sample surface. This bombardment causes the sample material to ‘sputter’, essentially knocking free atoms or molecules of analyte material, which are then drawn into the plasma where they are excited. The light emitted by this excitation is then diffracted to separate the wavelengths emitted by the specific elements and detected by a spectrophotometer. The intensity of the signal is directly proportional to the quantity of analyte element present in the sample, allowing simple calibration and quantitative determination of the elements. Technological improvements made in the past twenty years or so have significantly increased the usefulness of GD-OES for surface analysis. Faster plasma stabilization and start-up allow for the quantification of surface layers as thin as 1 nm. Sputter rates have been accurately measured for many common materials, allowing them to be built into software libraries in the instrument’s control software. This dramatically expands the usefulness of this software and the ease of performing analyses.GD-OES analysis of nuclear materials allows for the rapid determination of the elemental composition without the requirement of initial dissolution. The thickness of any corrosion layers on nuclear materials can also be determined."

Jan 1, 2015

There is a lack of information concerning the movements of water on the continental shelf, particularly with regard to data obtained regularly over significant periods of time. The Horace Lamb Centre for Oceanographic Research has recently deployed data acquisition systems on the sea bed off the coast of South Australia to record tides, swell, and ocean temperatures. Some of these early records are described. The swell data are pertinent to future offshore operations with drilling rigs, barges, and other equipment, while the temperature variations give evidence of significant bottom currents, apart from those due to swell.

Jan 1, 1971

By Stuart McTavish

"Noranda's Goldstream mine is a 1,500 ton per day copper-zinc mine located 60 miles north of Revelstoke, B.C.The orebody which contains 3.69% Cu and 2.69% Zn was discovered in 1972. Construction of the mine and mill was completed in 1982 and start up was achieved in May 1983.This paper will describe the flowsheet and related equipment 1n the crusher and mill, in particular the dewatering section where two Larox pressure filters are used to dry the concentrates.INTRODUCTIONThe Goldstrean property is located 60 miles north of Revelstoke, B.C. in the Goldstream River Valley (Figure #1). It was discovered during the construction of a logging road in 1972. Exploratory drilling was initiated in 1975, and in 1976 a portal was collared to obtain underground data. Samples were taken from the underground workings for metallurgical bench tests and a pilot plant run.Due to economic conditions, the decision to go into production was delayed until 1980. Concentrator construction and underground development progressed simultaneously during 1981 and 1982, and were completed by the end of 1982. Start up of the concentrator was achieved on May 2, 1983.The ore typically contains about 40% sulphides, which are chalcopyrite 10%, sphaletite 6%, pyrrhotite 20%, and pyrite less than 5%. The sulphide minerals have a high degree of intergrowth. Most of the sphalerite occurs in micron sized grains which are embedded in the pyrrhotite and, to a lesser degree in the chalcopyrite. There is also some fine dissemination of the chalcopyrite in the pyrrhotite. The waste rock is made up of about 30% quartz, 20% guange silicates, and 10% carbonates. The ore has a specific gravity of 3.2 and a natural pH of 8.2."

Jan 1, 1985

By I. W. Farmer

Weightings and water inflows into longwall workings often occur together, giving rise to discussions on their relative genesis. Case histories are introduced which indicate that most water inflows are associated with heavy weightings. Resultant large releases of energy can lead to extensive vertical fractures, which can drain water from aquifers or other sources, such as separation accumulations, onto the face. Effectively control of water inflows in these cases depends on face support and weighting control.

Jan 1, 1996

By G. M. Bond

Reduction of the emissions of greenhouse gases, such as CO,, is currently the subject of extensive research. A novel strategy is put forward here, based on a biomimetic approach providing accelerated deposition into carbonate form for long-term sequestration. It offers the advantages of a process that: does not require concentration of CO, from flue gases; could potentially be used in an on-site scrubber to provide a plant-by-plant solution to reducing CO, emissions; is an environmentally benign procss with an environmentally benign product; and is based on readily available, low-cost reagents (except perhaps the catalyst).

Jan 1, 1999

The mineralogy of the rocks now observed in the Nairne pyrite deposit developed under conditions of internally-controlled sulphur activity during amphibolite facies metamorphism. In the sulphide-deficient metasediments the activity of sulphur was low, and pyrrhotite developed with iron-bearing silicate minerals. At higher sulphur activity, in the sulphide-rich meta-sediments, pyrite formed in addition to pyrrhotite, and the associated silicate minerals are iron-deficient.

Jan 1, 1969

By A J. H Newell

The background and the basis for conducting a Technical Due Diligence are discussed as well as the source information, typical studies and potential limitations. Typical short comings including ‘show-stoppers’ are presented for the metallurgical area, with examples. Issues found in other areas such as geology, mining, infrastructure and financial evaluations are briefly reviewed, highlighting the input and interaction required by metallurgists with these disciplines. A checklist is provided as a guide to maximise the success of a Due Diligence as well as a check on the quality of a Feasibility Study.CITATION:Newell, A J H, 2015. Fatal flaws in technical due diligences, in Proceedings MetPlant 2015, pp 61–77 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Eric S. White, Thomas J. Sabourin, Khuram R. Mohib

"This paper presents the challenges associated with the design and construction of a steel sheet pile cofferdam supported with one level of grouted anchors in clean to silty sand with gravel. The initial assessment of the subsurface conditions indicated loose to medium dense soil with intermittent dense to very dense layers with no occurrence of cobbles and boulders. Sheet piles were proposed to be installed to a depth of 24 m below the ground surface to limit dewatering requirements for the cofferdam. During sheet pile installation, refusal of piles occurred at multiple locations forming passages for increased flow into the cofferdam. Modifications were made in the design of the dewatering system as a result of the increased flow. Finite element modeling was used to select the necessary modifications to the dewatering system within the cofferdam. Wells were installed based on the findings of the numerical model. Model simulations showed good comparison with monitoring of the field installed dewatering system.INTRODUCTIONIt is necessary to consider the impact of the ground water, subsurface stratigraphy, strength, and drainage behavior of the soil for the design and construction of cofferdams. This paper presents a case history of the construction of a cofferdam in Northern Ontario, Canada. The project consists of the construction of a powerhouse, intake, and tailrace which will generate around 28 MW of renewable clean energy by diverting water from New Post Creek through a power house and discharge into the Abitibi River. The focus of this paper is the dewatering and excavation support required to permit construction of the powerhouse. The layout of the cofferdam is shown in Fig. 1. The cofferdam for the powerhouse is rectangular in shape with sheet piles on all four sides intended to be driven to the design toe El. 101 m. The east and west walls have a length of 46.3 m. North and south sides are 47.6 m long; and in addition, two cantilever sheet pile walls bound the tailrace on the west side and two cantilever walls were installed on the east for construction of the penstock inlet. The ground surface in the powerhouse cofferdam area, before commencement of sheet pile driving, was brought to El. 125; the ground then slopes up to the East, toward New Post Creek, and the site is bounded on the West by the Abitibi River. 186 pairs of sheet piles were used to create the cofferdam and cantilever walls. The deepest excavation is to elevation 114.4 m. Within the west half of the cofferdam footprint, the base of excavation slopes upward at 3H: 1V to facilitate the tailrace discharge into Abitibi River.SOIL STRATIGRAPHYThe cofferdam design was based on the geotechnical investigation conducted by AECOM (2014) which included two relevant boreholes near the powerhouse footprint. The ground elevation at the time of investigation varied between 131 to 129 m. The material observed to the full depth of investigation was comprised generally of coarse to fine sand and gravelly sand or a sand matrix with gravelly inclusions. Some intermittent layers of clay and silt intrusions were also observed. Generally the soils grade finer away from the river. SPT N60 values were recorded in two borings during the field investigation with values reported from 3 to 92. The in-situ conditions ranged from compact to dense with some loose and some very dense zones. Figure 2 shows the variation in SPT N60 values with elevation."

Jan 1, 2017

By Andreas Hucke

For the roadway design in the German hard coal mining industry, an advanced combined planning system has been applied during the past 20 years. The German mining industry is working with single entry roadways system. After first longwall passage the roadways will be stabilised with side wall building material packages. Later this roadway will be used again for the second retreating longwall. The intention of the implementation of several different design methods for the planning of the roadways is to enhance the reliability of the results. On one hand the planning system uses numerical simulation and physical modelling in addition to analytical and empirical methods. On the other hand in-situ monitoring and analysis during the roadway development will be used to verify and calibrate the numerical and physical models. Especially before the implementation of new support elements in underground, this system is suitable and reasonable because the new support elements will be tested in the physical and numerical simulation prior to cost intensive underground tests. The interaction between the numerical and physical modelling in comparison with underground monitoring and analysis during development and the later use of roadways will be shown with some examples. The first example shows a rock bolted rectangular roadway which will be mined at both sides of the roadway. Different support and roadway building material package systems are investigated under various stress conditions. The results are utilised to optimise the roadway support and the roadway side package systems. The influence of different points in time of the installation of several support elements in a combined arch and bolted roadway is shown as another example. Two different types of support systems are compared within the physical models. These models are used as a base for ongoing numerical analysis and simulation to find out the ideal point of time to assemble the different support elements. The last example handles the influence of slickensides in the roof of arch shaped roadway on their stability. Different slickenside positions and densities are investigated and classified.

Jan 1, 2006

By L. Bryson, J. H. W. M. Brits, K. Voogt

"The Anglo American Platinum’s Rustenburg Base Metals Refinery (RBMR) has the world’s first full deposit nickel plating tankhouse. Impurities in the nickel electrolyte can induce stresses in the electrowon nickel deposits that could lead to delamination of the deposit. Identifying the impurities that contribute to increasing internal stresses in the nickel deposit is key to successful operation and automation of the tankhouse. Impurities were introduced in the plant electrolyte and the effects on the full-scale nickel deposits evaluated. The impurity-adjusted electrolyte solutions were also analyzed using commercially available bench-scale methods to determine the induced stress. A correlation between impurity-induced deposit stress and full-scale delamination was developed. A direct correlation can now be made between feed quality, i.e. impurity concentrations, and degree of delamination in the plant. This methodology has the potential to rapidly predict the effect of new reagents, upstream process upset conditions and synergistic interactions between impurities on deposit stress and delamination of nickel deposits.INTRODUCTION Nickel electrowinning in sulphate media was first pioneered by Outokumpu in its Harjavalta refinery in 1960 (Saarinen and Seilo, 1985). The original process was very manual with starter sheets plated onto “acid resistant” steel for 36 hours and then manually stripped and cut into sheets which could be inserted into the main production cells for a further 4–5 days. The starter sheet stripping and manufacture process was later automated. The same technology was subsequently implemented on a number of plants around the world. Anglo American Platinum’s Base Metal Refinery (BMR) began nickel electrowinning in the early 1980’s. The recent expansion of Anglo American Platinum’s Base Metals Refinery necessitated the construction of a new nickel tankhouse to achieve two primary objectives. The first to increase the capacity to 32 400 tpa nickel and the second to reduce employee occupational exposure to nickel aerosols. The new tankhouse has been commissioned and is in the process of ramp-up; more details are given by Hagemann et al. (2016). Fundamental to lowering employee exposure to aerosols was automating both harvesting and final handling of cathode. In order to accomplish this a bold move was taken to plate up to 10 days on permanent titanium blanks which are harvested by automatic crane and automatically stripped. The original development work for the plating nickel on titanium blanks over a ten day cycle is given by Bryson et al. (2006)."

Jan 1, 2017

The sequences in alteration and mineralisation from five copper-gold porphyry systems (Taysan and Didipio, Philippines; Horse-Ivaal and Wafi River, PNG; and Goonumbla, Australia) and one gold-copper skarn system (Browns Creek, Australia) are documented in this paper. Alteration and mineralisation in all these systems reflect a common evolution from crystallisation of melts emplaced at shallow crustal levels (zoned potassic -> propylitic alteration), followed by exsolution of volatile-rich fluids from these melts (porphyry quartz ¦K-feldspar/biotite veins and local high temperature advanced argillic alteration), to a progressive cooling of the intrusion which results in associated retrograde alteration. Copper-gold mineralisation in all cases is almost exclusively restricted to the cooler retrograde events. The recognition of the temporal and spatial zonations in alteration and mineralisation in gold-copper porphyry systems has significant relevance in the interpretation of geophysical signatures, overprinting alteration, vein sequences and structural controls, and can lead to more focused and potentially more cost-effective exploration.

Jan 1, 1999

By Zuhair A. Nawab, Muhammad A. Al-Marhqun, Mehmet Guney

"The Atlantis-Il-Deep is a stratified metalliferous deposit located along the median valley of the Red Sea at a water depth of about 2200 m. The metal-bearing mud contains sulphides of zinc, copper and iron with significant amounts of silver, gold and cobalt. A variety of oxide, siliceous and carbonaceous gangue material is also present. Long sediment cores indicate that the thickness of the deposit may reach 25 m, but the average kriged thickness of metal-rich sediments is about 11 m.Mining geostatistics was applied to estimate the Red Sea offshore mineral resources. Experimental semi-variograms were computed along 0 ± 180 degrees and then models were fitted to analyze the mineralization phenomenon. Kriging estimates indicate that 696.330 million t of bulk sediments contain 1.891 million t of zinc, 0.425 million t of copper and 3. 75 thousand t of silver. Gold and cobalt contents were calculated from the analysis of solids in flotation concentrates as 47 t and 5368 t respectively. The significant outcome of implementing geostatistics to the Red Sea brine precipitates is not only for the evaluation of metal resources, but it also provides a useful tool in the optimization of selective dredging of appropriate areas to be mined. IntroductionThe discovery and extensive exploration of hot brines and hydrothermal sediments in the Red Sea median valley revealed the fact that the Atlantis-II-Deep is a potentially exploitable metalliferous mud in the economic sense. Sediments in the mineralized deep are composed mainly of oxides, various types of silicates and sulphides with considerable concentrations of zinc, copper, cadmium, silver and gold. The mineral-rich deposit, located at a mean water depth of about 2000 m, has an average thickness of 11 m, and is covered by a brine layer having a temperature of 60°C."

Jan 1, 1988

By T. Bajpayee, J. Ellenberger

Microseismic monitoring and evaluation is one aspect of the National Institute for Occupational Safety and Health (NIOSH) research program. Roof falls are often preceded by a period of elevated microseismic activity, but not all periods of elevated activity result in a roof fall, nor do all roof falls occur after some amount of elevated activity. The objective of this study is to review periods of elevated microseismic activity and determine whether fracture activity rate can be used to anticipate the initiation of roof falls. The study was carried out at an underground limestone mine where major roof falls are associated with excessive horizontal stress. The progression of roof falls was detected by the microseismic signature produced by the rock falling from the mine roof onto the mine floor, which is termed a roof fall impact event. A total of nine elevated fracture activity periods that resulted in seven major roof falls were examined. It was observed that elevated fracture activity preceded the initial roof fall impact event in three out of four major roof falls. The initial impact event was not identified for the remaining three roof falls. Fracture event rates were analyzed and a roof fall alarm trigger of five fracture events in a ten minute time period was established for this test case. The fall alarm trigger was tested against six of the elevated activity periods. Four roof falls occurred in the six periods of elevated activity, and two would have triggered the alarm before the roof fall occurred, while two false alarms were generated. The results show that limited success would have been achieved by the microseismic system as a roof fall alarm trigger. However, the trigger would have been successful at warning of the onset of elevated activity, allowing mine employees to respond appropriately. The study highlighted some issues with implementing such a system in an operating mine, including the need for real time identification of fracture related microseismic signals among mining induced signals, and accurate location and identification of fracture clustering.

Jan 1, 2007

By Douglas F. Scott

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied an 11,980-acre part of the 33,300-acre High Rock Canyon Wilderness Study Area, CA-020-913B, in order to evaluate its identified mineral resources. No mineral resources were identified during this study, and no significant amounts of gold, silver, mercury, gem-grade opal, or placer gold are present. The study area is located in Washoe County, NV, about 53 miles southeast of Cedarville, CA. No mining districts or mineral production are known, and no oil and gas leases are in the area. No current claims are in the area; however, six placer claims were located in 1911 in High Rock Canyon near its confluence with Mahogany Creek.

Jan 1, 1987

By Meagan S. Boltz

From October 2000 to April 2001 a local array of fourteen seismograph stations was deployed at the Trail Mountain Mine (TMM), an underground coal mine in Emery County, Utah, to locate mining-induced seismicity (MIS). Original analysis of the data provided epicentral locations that coincided closely with the active longwall panel. The original analysis yielded poor quality hypocenters, however, preventing a useful relation from being made between mining activity and the event depths. For the original analysis, only stations at elevations above mine level were used for locating MIS. As a result, P- and S-arrival times from four of the stations in the local array were not used: an inmine station and three stations at elevations below mine level. This study compares mine workings and active mining to a revised TMM dataset that included P- and S-arrival times from the lower elevation stations that were not used in the previous study. In the revised locations, a modified master event methodology was used to calculate station delays. These station delays correct for errors in the shallow layers of the velocity model. The resulting hypocentral locations have improved depth resolution, determined by a lower root mean square (RMS) for the locations, compared to the original study. Most of the events occur in the roof of the mine and follow the longwall panel. When located using the velocity model determined in the original study, the elevations of the events increase as the longwall panel progresses. One possible explanation for the elevation increase is that it may be related to geology or the caving process. As presented here, a 10% decrease in the shallow velocity structure results in a more plausible location for the hypocenters. Consequently, it is hypothesized that progressive development of the TMM longwall panel(s) may have resulted in a progressive change in the velocity model.

Jan 1, 2012

By S D. C Rabone

An elongate belt containing granodiorite stocks with associated stockwork molybdenum mineralisation in west Nelson is correlated with the I-type Separation Point Suite of mid Cretaceous age. Trace element characteristics of the 'Mo-granites', and the Separation Point Batholith strongly suggest a primitive, subcrustal origin for these granitoids, by partial melting of oceanic basaltic crust or upper mantle material in a subduction zone. They were emplaced in the upper crust without undergoing significant differentiation or contamination by sialic crust. Molybdenum, which is at levels of approximately 5 ppm in unaltered granite, is not significantly reduced in altered (but unmineralised) granite. This suggests the metallisation has a magmatic, subcrustal source and is not derived by hydrothermal leaching of upper crustal rocks or the granitic host rocks. Geochemistry of the 'Mo-granite' belt, in particular low K2O, calc-alkali to calcic Peacock Index, high Sr and TiO2, and low Rb, Nb and F, suggest classification as calcic granitoids similar to those which host porphyry copper deposits, indicating grades of mineralisation are likely to be low.

Jan 1, 1987

By A. M. Neale

Kriel Colliery has experienced some sub-standard blast results on the overburden. Blast results are considered poor when the fragmentation is too big, back break into the new highwall, capping is experienced and/or excess overburden material is thrown into the void. Poor blasting leads to lower productivity, equipment breakdowns, and poor drilling and blasting results on the adjacent blast, contamination of coal or loss of coal. A simulation was developed in Microsoft Excel to model blasting results while changing various parameters. From the simulation results, it could be seen that a change of blast design could be beneficial. As an example, smaller drilling patterns were simulated (10 m x10 m to 8 m x8 m, and 8 m x8 m to 7 m x7 m in Pit 5 and Pit 6 respectively) in combination with changes in explosives (P700 emulsion vs. ANFO) and drill bit diameter (311 mm vs. 251 mm). The results show that each of the options has a specific scenario that will be most beneficial to the mine. These results are quite specific and subject to variable inputs. The purpose of the example is to demonstrate how the simulation can be used as a tool to asses blast design variations.

Jan 1, 2010

A series of electron beam, cold hearth, single melt Ti-6Al-4V plates (nominally 2.5 cm thick) impacted by 2cm diameter, 4340 steel projectiles (with 54g nominal mass) at velocities ranging from 0.633 to 1.027 km/s were sectioned along the impact axis and examined by optical metallography to characterize the formation, growth, and microstructure of adiabatic shear bands. Near ballistic limit velocities, the shear bands propagate towards the rear of the target where they coalesce and grow to provide a cylindrical solid state flow regime for the plug volume.

Jan 1, 2006