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At Bulong, the mineralised (>0.8 per cent nickel) ore exists within numerous lithologies, which can and do occur coincidently. It is very important to discriminate between the different host units for estimation purposes, stockpiling and scheduling. This allocation of host unit has relied upon visual interpretation by the geologist recording the information, which can be very subjective by its nature. By using quantified constraints, such as assayed magnesium oxide and iron, the subjectivity of describing the host material of nickel laterite ore is reduced. The constraints permit consistent identification of the various host units, which improves the confidence in the overall estimation and scheduling of the ore.

Jan 1, 2000

By E. L. Montgomery

Salar basins in the Andean Highlands of Northern Chile contain ground-water resources which could be used to satisfy requirements for the mineral industry in the region. Salars occur in arid zones; average precipitation is about 200 millimeters per year at altitudes of about 4,000 meters, and average annual evaporation is two meters or more. The salar basins are hydrogeologic sinks where water flows from recharge areas at the margins of the basins to discharge areas at the salt encrusted salar at the lowest point of the basin floor. Groundwater circulation occurs principally in the alluvial and fractured bedrock aquifers. Results of pumping tests for exploration and production water wells indicate a range in maximum sustained pumping yield of 62 to 126 liters per second, and where abundantly fractured, ignimbrite comprises the most prolific aquifer. Chemical quality of groundwater is good. Long-term pumping from properly located production wells in the salar basins would result in lowering of groundwater levels and salvage of water in areas where groundwater is lost via evaporation.

Jan 1, 1986

By S. I. Anufrieva, N. A. Permyakova, E. G. Likhnikeevich

"Russia’s rare metal reserves are composed of compositionally and structurally complex ores and are characterized by an increased content of natural radionuclides due to their geochemical similarity with rare metals. For instance, concentrates of Zashikhinsky daeposit are characterized by an increased content of uranium (0,06%) and thorium (0,59%); Beloziminsky deposit holds pyrochlore-apatite-magnetite-carbonate ores characterized by increased radioactivity (130 mkR/h) and containing 0,0016-0,0025% of uranium; Etykinsky deposit is characterized by columbite-pyrochlore-microlith mineralization with an average ore grade of 0,013% of uranium and 0,0020% of thorium; eudialyte concentrate of Lovozero deposit (Alluaiv area) belongs to Class II of mineral reserves. Industrial development of these mineral reserves involves the need to comply with environmental standards, public health requirements applicable to finished core and by-products, to take into account the amount and class of the generated radioactive waste, the possibility of disposal or recycling of the radioactive production waste. Concentration processes of radioactive rare metal feeds most often lead to a concentration of natural radionuclides and their accumulation in concentrates. Comprehensive hydrometallurgical processes are currently under development for such concentrates, aimed at producing salable products compliant with the radiation safety standards. The choice of the hydrometallurgical processing method for radioactive rare metal concentrates is based on the mineralogical component of the concentrate, textural and structural features, the distribution of valuable components and impurities, and the content of radionuclides. A systemic approach to the selection of processing methods, in particular integrating several methods, is an effective solution. Methods may not only be combined, but also inextricably linked with each other. Hydrometallurgical processing methods include leaching by acidic and alkaline agents; sulfatization for selectively decomposing the minerals and moving the bulk of U and Th into solution; fluorine extraction process. Methods of precipitation and co-precipitation, extraction (by liquid and solid extractants), sorption, and ion exchange are used to decontaminate the solutions by removing thorium, mezathorium, uranium, and their radioactive decay products. Agents used in hydrometallurgical processing of radioactive rare metal ores include sulfuric, nitric, hydrochloric, hydrofluoric acid, alkali (NaOH, KOH), sorbents (for example, AB-17) for sorption of uranium and extractants (mono- and bidentate organophosphorus compounds, diamides, etc.) for the extraction separation of rare, rare-earth, and radioactive elements."

Jan 1, 2018

By V. Nasri, S. Rashidi

The Baltimore Red Line Project is a proposed 22.7-km (14.1-mile) long east-west light rail transit (LRT) line envisioned to connect the areas of Woodlawn, Edmondson Village, West Baltimore, downtown Baltimore, Inner Harbor East, Fells Point, Canton and the Johns Hopkins Bayview Medical Center Campus. The Red Line LRT System has two tunnel segments - the Cooks Lane Tunnel (CLT) and the Downtown Tunnel (DTT). The CLT segment is roughly 1,920-m (6,300-ft) long. It commences at the west portal located at the highway ramp for I 70 (to be removed) and terminates at the east portal that is at the intersection of Edmondson Avenue (U.S. Route 40) and Glen Allen Drive. This segment of the project consists of the following construction components: approximately 1,458 m (4,786 ft) of tunnels, 143 m (469 ft) of cut-and-cover tunnel, and 318 m (1,045 ft) of retained cut (U) section. The approximate horizontal alignment for the Red Line LRT Project is shown in Fig. 1.

Jan 1, 2014

By R. F. Korcak

There exists a wide array of industrial by-products that can be shown to produce beneficial responses in the soil/plant environment. These materials range from clean coal technology residues produced in the generation of electric power, particularly those high in gypsum, to mineral 'fines' produced by the aggregates and crushed stone industries. A number of these materials will be examined in relation to potential nutritional interactions in soils and crops with emphasis on trace elements. The significance of utilizing these materials in agriculture as a component of sustainable agricultural systems will be discussed.

Jan 1, 1995

By W. R. McDonald

The U.S. Bureau of Mines investigated treatment of gold and silver refractory ores and concentrates that respond poorly to conventional cyanidation techniques due to the complex mineralogy of the ore. Three types of ores were investigated: gold locked placer sands, gold locked in sulfides, and gold that is robbed from the pregnant cyanide solutions by minerals in the ore. Ore treatment included grinding, flotation, cyanidation, air oxidation, pressure oxidation, hypochlorite oxidation, roasting, and carbon in leach.

Jan 1, 1991

By A Noack

Today underground infrastructures, like tunnels and especially wide spread underground mines, are often equipped with ethernet based communication systems. These networks are used for the unified communication of data, voice and video. As these networks stretch along the major tunnels and in increasing scale also into the production areas, a high degree of coverage can be reached. For wireless coverage, standard IEEE 802.11 WLAN access points are being used. In order to provide a maximum availability and reliability, the active components are equipped with battery backup power supplies and the network infrastructure is set up in a redundant way using ring or meshed topologies. This provides a much higher availability compared to traditional phone systems or dedicated data links using a conventional star topology.Distributed computing intelligence that is installed on active network nodes throughout the whole network, additionally supported by a central server system, creates the basis for new mine safety functions introduced in this paper for both coal and non-coal mining. These new safety functions cover the detection of potential emergencies, using the status of the network as a æsensorÆ, as well as dynamically guiding people to safe exits or rescue shelters in case of an emergency. Furthermore, these functions are of important benefit for improving the efficiency of search and rescue operations following a major incident or accident underground.

Sep 26, 2011

By C. Peter Hayes

The world continues to change and with it the supply of minerals and metals, the location of centres of production of primary metal and the increasing levels of metals and materials recycling. New technologies are being developed to meet the ongoing search by industry for lower costs, cleaner production and new markets. To keep abreast with these changes, and to utilise fully, the potential benefits of these technical advances, the industry will need a professional workforce having different knowledge, skills and professional attributes than in the previous millennium. What are these skills and attributes? How to best attract and develop the metallurgists of the future, and provide for the ongoing educational and research needs of the industry?

By T. H. Jeffers

The U.S. Bureau of Mines' Salt Lake City Research Center. has developed porous polymeric beads containing immobilized non-living biological materials for extracting metal contaminants? from wastewater&. Immobilized biological materials include peat moss, algae, biological polymers, and other materials that demonstrate high .affinities for heavy metals. The beads, designated as BIO-FIX beads, have distinct advantages over traditional methods of utilizing biological materials in that they have excellent handling characteristics . and can be used in conventional processing equipment or low-maintenance systems.. Toxic metals such as copper, cadmium, zinc, lead, and mercury are several of the many heavy metals effectively removed from mine wastewater& using B'IO"FIX beads. Continuous cyclic testing indicated that the beads continued to produce treated effluents which met National Drinking Water Standards (NDIJS) after 175 loading-elution cycles, Adsorbed metals were removed from the beads using dilute ?mineral .acids. In many cases" the extracted metals were further concentrated to enable processors to reclaim the metals, thus minimizing the generation of a hazardous sludge. Tests indicated that use of the beads in a low-maintenance system was particularly effective for treating remote acid mine drainage waters? and small toxic seeps from hardrock mining districts ..

Jan 1, 1991

By B. Y. Wong

In April 1989, Southern Company Services signed a 3.5 year contract with DOE-PETC for generic engineering development of an advanced physical fine coal cleaning technology known as selective agglomeration. This technology offers the potential for significantly higher pyritic sulfur removal (90% +) than conventional coal cleaning (30 to 50%) while maintaining high Btu recovery (90% +). Engineering development will include bench-scale process development; component development; adaption or modification of existing unit operations; proof-of-concept (POC) module design, fabrication, testing and evaluation; and small commercial facility conceptual design. The information obtained during POC operation will be sufficient to result in a technical and economic design base that can support construction and operation of a small commercial plant. The major goal of the research is to develop selective agglomeration technology to achieve 90% pyritic sulfur removal while operating at Btu recoveries above 90% based on run-of-mine quality coal. This objective will be accomplished in two phases: Phase 1 -bench-scale and component development, and Phase 2 -POC module operation and conceptual design of a small commercial plant. Currently, work is proceeding under Phase 1 (Tasks 1-7) of the project. A review of the status of Tasks 1-7 is presented in this paper.

Jan 1, 1991

By R Moreby, J Kok, L van den Berg

The high production rates achieved from mass mining methods such as block caving, sublevel caving and longwall mining require large conveyor belts, trucking loops (diesel/electrical) and rail systems for ore handling. However, the ore handling systems used in mass mines introduce a significant amount of heat into the overall ventilation system, which may be problematic at depth or in mines located in hot climates.In particular, the heat load from a conveyor system is not always well understood and consists of various components, including frictional heat from idlers, heat from electrical motors, heat from the drive train and heat from broken rock transported on the conveyor system. This paper presents results from a study that investigated the heat introduced to the ventilation air from a large conveyor system. The conveyor system transports ore with a maximum virgin rock temperature of 41°C from a depth of over 1 km. Air, belt and rock temperatures were measured in the conveyor system to evaluate the distribution of heat loads.CITATION:van den Berg, L, Moreby, R and Kok, J, 2015. Heat load estimation from conveyor systems in mass mines, in Proceedings The Australian Mine Ventilation Conference, pp 63–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By M. Yekich, W. R. Reed, G. Ross, M. Shahan

"Canopy air curtains on roof bolting machines have been proven to protect miners from respirable dust, preventing their overexposure to dust. Another desired application for canopy air curtains is in the compartments of shuttle cars. The challenges faced in developing the design of canopy air curtains for shuttle cars include mine ventilation rates in tandem with the shuttle car tram speeds. The resulting cab airspeeds may exceed 182 m/min (600 fpm), as found in the present study conducted in a central Appalachian underground coal mine by U.S. National Institute for Occupational Safety and Health (NIOSH) researchers. Prior research and laboratory testing had indicated that successfully protecting a miner in high air velocities is difficult, because the clean air from the canopy air curtain is unable to penetrate through the high-velocity mine air. In this study, the dust concentrations to which a shuttle car operator was exposed were measured, and air velocities experienced by the operator were measured as well using a recording vane anemometer. The results indicate that the highest exposure to respirable dust, 2.22 mg/m3, occurred when the shuttle car was loading at the continuous miner, where the average airspeed was 48 m/min (157 fpm). While tramming, the operator was exposed to 0.77 mg/m3 of respirable dust with an average airspeed of 62 m/min (203 fpm). This study indicates that a canopy air curtain system can be designed to greatly reduce an operator’s exposure to respirable dust by providing clean air to the operator, as the majority of the operator’s dust exposure occurs in air velocities slower than 61 m/min (200 fpm). IntroductionThe U.S. National Institute for Occupational Safety and Health (NIOSH) issued contract #200-2015-63485 to develop a canopy air curtain for coal mine shuttle cars with Marshall University and J.H. Fletcher & Co. (Salem, Begley and Ross, 2016). The proposed design maintains a design similar to that of a roof bolter canopy air curtain by providing filtered air through a blower over the operator. The plenum, which will provide uniform airflow over the operator, is anticipated to be built into the shuttle car canopy. One of the main interferences with a canopy air curtain is ventilation airflow perpendicular to the plenum airflow (Engel, Johnson and Raether, 1987). This ventilation airflow can shear the downward flow from the plenum, and this shear can reduce the effectiveness of the canopy air curtain by either disrupting the downward flow or allowing contaminated mine air into the canopy air curtain zone of protection."

Jan 11, 2018

By Peter J. Nicholson

During my more than 40 years in the practice of underground construction and engineering, the industry has seen progress from the dig down to rock or hardpan or alternatively drive concrete or steel into the ground and count the blows; then you can be sure of you have a solid foundation; to the modern day, I?m willing to try anything to save money. Of course these are both exaggerations, but not gross ones. After getting bored being supervision on jobs counting blows, I struck out into the new field of ?tie-backs? as they were called in the United States, or ?ground anchors? as they were then termed in the United Kingdom. After installing some of the first permanent ground anchors for the Corps of Engineers on Lake Michigan as well as the highest loaded rock anchors of the time at two dams on the Ohio River, we were at the top of our game in the 1970?s. Subsequently in the 1980?s when my view of the future of ground anchors saw their installation becoming a commodity item, we branched out into ?Pin Piles? now known as Micro Piles, high capacity, steel tube encased, small diameter (5-12? or so), high capacity (100-500 tons) piling. Next came soil nailing, both temporary and permanent retaining walls, as at Cumberland Gap Kentucky. My next morph was into ?Cement Deep Soil Mixing? earlier on, known simply as ?soil mixing?. For this education I traveled to Japan several times and established a long-term, Joint Venture, relationship with one of the better known Japanese specialty ground modification companies. In Boston at the ?Big Dig? we established the then record size soil mixing project, 500,000 or so cubic meters of CDSM concluding in the year 2000. Since then I?ve been involved as a consultant mainly for dams and levees. Below is the story of how I came to be at this place in the road to innovation in Geotechnical processes.

By K. Thuro, H. Käsling, C. Wieser, G. Nuijten

"The time-dependent behavior of brittle rocks during stress relaxation is of great interest for mining industry, nuclear waste disposal as well as tunneling and underground construction. Several studies have shown that both elastic as well as inelastic deformation occur during stress relaxation (Emery, 1964; Zang & Berckhemer, 1989). While elastic strain occurs already during the drilling process, inelastic deformation is time-dependent and can endure for hours, days or weeks. To investigate the evolution of microcracks during core relaxation, two crystalline core samples were recovered from high in situ stress conditions in Europe’s deepest mine in Pyhäsalmi (Finland). Samples were prepared for testing within one hour after coring such that a large portion of the time-dependent component of relaxation could be recorded over several days using ultrasonic velocity as well as acoustic emission (AE) measurements.Results from AE analysis show an exponential decrease in the number of events over a period of several hours. Repeated sudden increases of acoustic events can be related to the propagation or the interaction of cracks. In the first hours of recording also the signal energies reached the highest values and the increases in signal energy correlate well with increased event rates. On additional drill cores, P-wave velocities were measured parallel and in 45° distances perpendicular to the core axis. After core recovery, stress-induced microcracking caused an exponential decrease in wave velocities similar to AE rates. Lowest compressional wave velocities were measured parallel to the core axis and thus normal to the foliation and in the direction of the maximum in situ stress component. The highest measured velocities occurred parallel to the foliation plane. Within the samples, the anisotropy ratios were up to 1.37 at the beginning of the measurements and increased to values of up to 1.8 after 45 days. The wave velocity anisotropy is in agreement with the in situ stress orientations."

Jan 1, 2015

ABSTRACT The inevitable uncertainty in modelling spatial variables decreases as more data become available. This reduction depends on the properties of the variable being modelled. Spatially continuous variables show less uncertainty for a given spacing than erratic variables. A geostatistical simulation based approach is developed to quantify the relationship between uncertainty and data spacing. Reference realizations are sampled to condition additional realizations and quantify uncertainty. The procedure is automated, making it straightforward to consider sensitivity and different geological domains. A case study of the relationship between uncertainty and data spacing for net oil sands thickness data from northern Alberta is presented. _ KEYWORDS Simulation, Sampling,

Jan 1, 2013

By J. P. Harrison, M. Grenon

"This paper summarizes the results of numerical studies on drift stability in moderately jointed rock masses. It investigates the relative pertinence of geomechanical factors such as joint orientation, spacing and stress regime. This is undertaken using a distinct element model and a series of parametric studies. IntroductionIn evaluating the stability of drifts in jointed rock, it is often necessary to compromise by employing models that capture the complexity of the rock mass, but which are still simple enough to allow for their routine implementation. The distinct element method can arguably provide an eloquent method to accomplish this. This paper explores the applicability of the method by means of a parametric study aiming to identify the dominant factors that influence the stability of drifts in moderately jointed rock. To this end a commercially available 2D distinct element numerical model was used. A series of techniques are presented in an effort to quantify the results of any instability predicted by the model.This paper also demonstrates a case study where a 3D joint network model was integrated into the distinct analysis software package. The advantages, as well as the current limitations of this approach, are discussed."

Jan 1, 2001

By T. R. Rehak

Blasting operations are an essential element in the recovery of our Nation?s mineral resources. The mining industry uses billions of pounds of explosives annually. The majority of blasting occurs in surface mining operations. Blasting results in the fragmentation and often the projection of rocks. Frequently, the rocks are thrown beyond the expected limits. Flyrock and failure to secure the blasting area dominate blasting-related accidents in mining, especially in surface mining. Blasting accidents in the mining industry tend to result in critical injuries or fatalities. Accident reports and information collected from the Mine Safety and Health Administration (MSHA) and other government agencies provide supporting evidence. According to the data collected, blasting-related accidents (in mining) were 11 times more severe than all other types of mining accidents. Blasting accidents are not unique to mining operations - the same situation exists in the construction field. In this paper the authors have compiled a list of the primary causes of flyrock and the failure to secure the blast area. In the next phase of this project, typical blasting scenarios will be reviewed which will highlight the main reasons flyrock and/or lack of blast area security occur. This will alert miners and construction workers to the current problems/hazards associated with blasting and to identify other safety measures to protect personnel.

Jan 1, 2000

By M. A. Vos

"Aggregates are the low-cost mineral raw material of building construction. Large volumes of aggregate are consumed each year. The availability of aggregates in southern Ontario is discussed in the context of the geological formations in which they occur. Sand and gravel are abundant in glacial deposits and in recent sediments. A knowledge of the glacial history is important for their discovery. Bedrock formations provide a variety of aggregates in Ontario. Knowledge of the rock types involved and of the depth of overburden are important for evaluation of the aggregate potential of bedrock resources in an area. Utilization of available resources intensifies as the population increases. Urban development makes it progressively more difficult to satisfy the demands of the construction industry. The effects of urban development on the aggregate resource base of an area are illustrated by developments and consumption statistics in the Toronto- centred region. There is an obvious need for a comprehensive survey of available resources in urban areas to serve as a guide in land-use planning. To fill this need, staff members of the Industrial Minerals Section, Geological Branch, Ontario Department of Mines and Northern Affairs, are engaged in mapping projects and mineral resource studies in southern Ontario as well as in some urban areas of northern Ontario."

Jan 1, 1972

By N. Sarmady, Mei Li, N. C. Parson, W. J. Poole

"The mechanical behaviour of AA6082 is a function of the extrusion conditions and in particular, the quench rate after extrusion. It is well known that precipitation of Mg-Si phases on grain boundaries during quenching can negatively affect the ductility of the alloy. In this study, AA6082 alloys containing 0.5 wt. % Mn and 0.15 wt. % Cr were direct chill (DC) cast, homogenized and then extruded to produce 3 mm x 42 mm strips. The microstructure in the as-extruded strips was unrecrystallized due to the Zener-Smith drag from the Mn/Cr dispersoids. It was shown that a solution treatment of 5 minutes at 560°C did not significantly affecting the as-extruded microstructure but if the as-extruded strip was cold rolled prior to heating, recrystallization occurred concurrently with the solution treatment. As such, 3 initial microstructures were produced, i.e. unrecrystallized and recrystallized with a grain size of 9 and 40 µm. After the solution treatment, controlled cooling experiments were conducted using the Gleeble 3500 thermomechanical simulator with cooling rates of 10, 25, 80°C/s as well as water quenched. The mechanical properties (e.g. yield stress, fracture stress and fracture strain) were determined from tensile tests for the different combinations of initial microstructure and cooling rate. The relationship between the quench rate and precipitation of Mg-Si phases on grain boundaries was examined by FEG-SEM. It was found that the yield stress decreased as the cooling rate decreased and that there was complex relationship between the fracture properties and the microstructure.INTRODUCTION As the automotive industry strives to reduce fuel consumption and CO2 emissions with the goal of reducing the environmental impact, there is a need for lighter vehicles. As a result, aluminum alloys are gaining popularity to replace steel parts as structural components. An exemplar of this is the Ford F-150 pickup truck which has an aluminum body and is ˜750 pounds lighter than the previous steel version of the vehicle. The structure includes a mix of aluminum sheet, extrusions and cast alloys. The current research is concerned with the performance of aluminum extrusions in applications such as side rails, crash tubes and other structural parts. These components experience a combination of bending, stretching and folding both during the forming of the part and in service, e.g. crash of a vehicle. There is a need to have detailed information on the influence of processing on final material performance, in particular the cooling rate after extrusion."

Jan 1, 2018

By M Brady, O Salisbury, C Claassen, B Beamish, H Baxter

Monitoring for signs of elevated spontaneous combustion in the active goaf behind the longwall face is crucial for early intervention of any potential heating incidents. Typically, trigger action response plans (TARPs) are established at the start of longwall mining and often are only reviewed when triggers are activated frequently and become ‘nuisance alarms’, or in the worst case scenario after a heating event. Narrabri Mine has adopted a proactive approach of reviewing the longwall active goaf spontaneous combustion monitoring TARP at the commencement of each longwall block and prior to reaching a known ‘mylonite zone’ of crushed coal, which is associated with increased coal oxidation. The review is based on information recorded from the monitoring data of the previous longwall blocks as well as interpretation of relevant spontaneous combustion propensity results for the coal. This has resulted in the mine implementing a zoned TARP approach for each longwall block covering both the longwall retreat through normal undisturbed coal and the zone where the goaf is influenced by the increased coal oxidation associated with the mylonite coal. The consequence of this approach is that it has removed the issue of having nuisance triggers being activated during mining through a known increased oxidation zone, while maintaining a high awareness of indicators of spontaneous combustion.CITATION:Baxter, H, Claassen, C, Salisbury, O, Brady, M and Beamish, B, 2015. Implementation of a zoned trigger action response plan associated with changing mine conditions at Narrabri Mine, in Proceedings The Australian Mine Ventilation Conference, pp 113–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015