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The Northside Storage Tunnel Project in Sydney includes over 20 km of TBM driven tunnels, over three km of declines and major caverns and pump rooms. The paper describes methods used for design on the project. Emphasis is given to the refinement of the use of empirical rock mass classifications, and to the use of discontinuum numerical methods. The use of empirical rock mass classifications in Sydney sandstone has usually led to conservative design because the systems are based on a random orientation of joints in the rockmass. Because the joint sets are usually oriented in a way that is beneficial for tunnelling, limits must be placed on the parameters used in the classifications system. The paper discusses these limits and the derivation of the parameters. The use of numerical methods in Sydney sandstone is discussed. Continuum methods have their uses, but discontinuum methods are preferred. The use of UDEC has been validated against a previous project, the New Southern Railway. Recommendations are given for UDEC models. In Sydney's geology, so advantageous for tunnelling, the challenges of this project have been to make the best use of the good conditions, while maintaining safety for the workforce and the future operators of the project.

Jan 1, 1999

By W. R. Reed

NIOSH continues to conduct respirable dust control research for surface mine blasthole drilling operations. Research areas have included testing variables (shroud leakage area, drill deck cross-sectional area, shroud height, collector-to-bailing airflow ratio, etc.) that have the most impact on respirable dust control, development of a dust collector inlet hood, development of a dust collector dump point shroud, and testing of a small diameter water separating sub. This paper summarizes the results of the aforementioned research that has been completed. Additionally, past dust control research for drilling operations of both underground and surface mines completed by the U.S. Bureau of Mines, created in 1910 and incorporated into NIOSH in 1997, is reviewed.

Jan 1, 2008

By S. Potgieter-Vermaak, T. T. Chiweshe, W. Purcell

The advantage of using ammonium phosphate salt as flux is the selective precipitation of chromium(III) compounds, which are considered nontoxic and environmentally friendly. The technique in this paper is determined to have potential to be applied in the metallurgical industry, where it can be used in the beneficiation of chromite mineral ores. The higher chromium contents of chromite ores often require furnaces to run at higher temperatures of above 1,300 °C, which can cause shutdown of the ore processing plant and accumulation of the sticky chrome compounds — including toxic chromium(VI) waste — which are generated as byproducts. The other advantage of this technique is its low to moderate energy consumption compared to existing techniques.

By Kadri Dağdelen, Matthew Deutsch, Thys Johnson

Nested pit analysis in open-pit long range mine planning is used to define approximate ultimate pit limits and an initial high-level schedule in the early stages of a project. Modern ultimate pit optimizers can solve for dozens, or even hundreds, of nested pits however often a smaller subset of pits which are evenly spaced with respect to contained tonnage are desired for downstream analysis. In situations where that pushback selection process must be automated, such as when performing sensitivity analysis, or when the best subset of pushbacks is required; an optimization procedure is warranted. This paper describes a dynamic programming algorithm for selecting pushbacks following nested pit analysis, which is performant and addresses a long-standing inconvenience faced by long range open-pit mine planners.

Jun 25, 2023

By Peter Ralph

All copper ore haulage at Isamine was transferred to the new 19 level haulage network by mid 1975. Previous experience together with design studies had indicated that a three train operation would be required to haul the scheduled ore production. The ore train with a gross weight of 600 tonne is made up of 15 bottom dumping trucks hauled by twin electric locomotives (Figure 1). Present train speeds reach 40 km/hr and, in the future, this speed could be increased to 55 km/hr. The planned operation on the restricted track network and the relatively high train speed meant that the train driver operated block light system would be inadequate on the grounds of haulage safety and meeting production targets. Some form of Centralised Train Control (CTC) system emerged as a necessity, and as an initial step, tenders were called for a relay control type CTC system. The high cost of these systems and the anticipated high maintenance costs and inflexibility of the offered systems led to the rejection of the tenders. It was decided to develop a CTC system locally and to use a digital computer to perform the basic track [ ] equipment interlocking tasks and monitor haulage operation.

Jan 1, 1979

By Yuting Xue, Gamal Rashed, Zoheir Khademian, Morgan Sears

Mining has been recognized among the most hazardous industries in the United States, despite the significant reduction in injury and fatality rates over the past century. This study focuses on the ground-fall incidents classified in the Mine Safety and Health Administration (MSHA) database as “fall of roof, back, or brow from in-place” and “fall of face, rib, pillar, side, or highwall.” The main objective of this study is to conduct a comprehensive statistical analysis of the reported ground-fall incidents from 2010 through 2019 including both coal and metal/non-metal mines. Since most of the ground-fall injuries and fatalities occurred in underground coal mines and were attributed to falls of roof and rib, an additional analysis was directed to evaluate roof- and rib-fall incident trends in underground coal mines associated with the mining method, coal-seam thickness, mine size, and the seasonal effects.

By J. -B. C. Varnier, J. A. Cremeens, D. D. Overton

"Slope failures that occurred in 2008 and 2009 at the Pikeview Quarry in El Paso County in Colorado in the United States were investigated using three-dimensional discrete element modeling methods. Large-scale block sliding failures occurred along weak bedding planes that dip steeply into an excavation located at the toe of the slope. Several mining sequences at the toe of the slope were simulated to evaluate the effects of various degrees of extraction and backfill on slope stability. Slope stability back-analysis was conducted using prefailure and post-failure conditions to determine the joint shear strength properties. Laboratory testing was also conducted to determine intact rock properties. Three-dimensional discrete element analysis was uniquely applicable to this evaluation because it allowed representation of shear stress of the basal sliding surface and afforded evaluation of several scenarios of extraction and backfill at the toe of the slope. IntroductionThe Pikeview Quarry is an aggregate quarry located approximately 8 km (5 miles) northwest of Colorado Springs in El Paso County, CO, USA. The quarry has been operated by several owners since the early 1900s. According to the U.S. Mine Safety and Health Administration (MSHA, 1986), the quarry has been a major source of construction aggregate for the Colorado Springs area for many years. In the 1950s, the site was mined by Peter Kiewit and Sons to provide limestone for the construction of the nearby Air Force Academy.A large-scale slope failure occurred on Dec. 2, 2008, which stopped mining activity at the Pikeview Quarry. A second, related slope failure occurred on Sept. 13, 2009. The second slope failure was located immediately adjacent to the initial December 2008 failure.The objective of this paper is to discuss the three-dimensional slope stability evaluation. The causal relationships of slope instability are not within the scope of this publication. However, omitting the precursors to slope failure would limit understanding of the nature of the slope stability evaluation. The regional and local geology and the history of slope instability at the Pikeview Quarry aid in understanding these precursors. Two main failure mechanisms were hypothesized during the failure investigation to explain the triggering of the 2008 and 2009 large slope failures at the Pikeview Quarry, and both of these mechanisms were given equal credence in the present study. Quarry excavation and backfilling was a key factor in the slope instability for both failure mechanisms. The excavation was backfilled in stages in an effort to provide slope support. The objective of the three-dimensional model was to evaluate the effects of extraction and backfill at the toe of the slope with respect to slope stability."

Jan 3, 2018

By Turan Uysal, Ramazan Aydogmus, MURAT ERDEMOGLU

The paper investigates the effects of calcination for thermal activation and intensive milling for mechanical activation on aluminum recovery by acid leaching of pyrophyllite ore enriched via attrition scrubbing and froth flotation. The study compares these methods in terms of energy consumption and aluminum recovery, concluding that mechanical activation is more economical and environmentally friendly.

Nov 1, 2023

By Tim Langmaid, Steve Skelhorn, Stephanie Robillard, Allen Mitchell

"The Port Mann Main Water Supply Tunnel project provides a critical water main crossing of the Fraser River for the owner, Greater Vancouver Water District (Metro Vancouver). The project consists of two 60-metre-deep slurry panel shafts and a 1-kilometre-long, 3.5-metre excavated diameter tunnel located near Vancouver, British Columbia, Canada. The initial tunnel lining is a precast concrete steel fiber reinforced gasketed segmental lining. The final lining is a 2.1-metre-diameter welded steel pipe. This paper describes the challenges encountered during tunnel construction and the solutions implemented. Key challenges include earth pressure balance tunnelling at up to 6 bar pressure—the highest to date in Canada—a water-crossing without surface access for the majority of the tunnel drive, ground freezing from a river platform for a critical TBM intervention, and boring through cobbles and boulders in dense glacial till. INTRODUCTION Metro Vancouver supplies drinking water to 18 municipalities, one electoral district and one treaty first nation, serving a population of more than 2.4 million residents. Water is collected in three mountainous watersheds to the north of the Greater Vancouver area, in southwestern British Columbia, Canada. To supply the growing demands of Metro Vancouver’s customers, treated water must be conveyed across two significant water bodies: the Burrard Inlet and the Fraser River. The existing Port Mann water main is one of several key links between the watersheds north of Vancouver and the municipalities south of the Fraser River. The Port Mann Main Water Supply Tunnel (PMMWST) is the first of a series of upgrades, to increase capacity, enhance scour protection, and improve seismic resilience. The new tunnel is 3.5 metres (11.5 ft) in diameter and 1 kilometre (0.6 mi) long. When completed, it will contain a new 2.1 metre (7 ft) diameter steel water main that will help ensure the continued, reliable delivery of drinking water to these municipalities, and will more than double the capacity of the existing 1.2 metre diameter main."

Jan 1, 2016

By S. Mohanta, S. Chakraborty, B. C. Meikap

"An air dense medium fluidized bed separator is an efficient dry process for the removal of undesirable gangue material from run-of-mine coal. Its cleaning performance depends on a variety of operating parameters that are interrelated in unknown, complex ways. A literature review showed that these parameters' effects had been experimentally investigated using a traditional one-variable-at-a-time approach, which is highly inefficient and sometimes misleading because many of the parameters often interact with each other to alter the overall equipment performance. Also, it is realized that the interrelationship among these parameters can have a significant effect on equipment performance. Therefore, to correctly evaluate the effects of individual parameters as well as their interactional effects on the separation performance of an air dense medium fluidized bed, we conducted a scientific study based on response surface methodology. Empirical models for two key response variables, namely, product ash and combustible recovery, were developed and subsequently used for identifying an appropriate operating region to achieve optimum separation performance. Furthermore, the optimum performances predicted from the empirical models were validated against experimental data. Preliminary results show a strong interaction among the operating parameters investigated in this test program.IntroductionFluidization is widely applied in industry for its various useful features. In the coal industry, it is used in the air dense medium fluidized bed (ADMFB) separator for the beneficiation of run-of-mine coal. In this separator, a medium is created by suspending fine magnetite particles in an upward air flow, and this pseudo-fluid is used as the beneficiation medium, with the lighter coal particles floating to the medium’s surface while heavier particles sink to the bottom. This separation technique had been receiving a significant amount of attention worldwide in recent times for its specific advantages of low operating cost and less restriction for small capacities (Luo and Chen, 2001; Sahu et al., 2009; Dwari and Hanumantha Rao, 2007; Van Houwelingen and de Jong, 2004), but it is still not a well-established industrial practice because of the availability of efficient wet processing technology. However, with a revival of interest in the dry beneficiation of coal, in general, and ADMFB, in particular, there is once again a concerted effort to improve the efficiency of the ADMFB process, and successive improvements have been made to make this process a competitive and viable option. The existing literature reveals that most of these research efforts had been essentially focused on the identification of a single parameter that has a key influence on separation performance, without taking notice of parameter interactional effect. For example, Luo et al. (2004) proposed a pressure drop number to distinguish separation performance without considering the bed height and gas velocity, which are intimately related to this proposed pressure drop number."

Jan 1, 2015

By S. Phillipson

The Mine Safety and Health Administration’s Roof Control Division (RCD) evaluated the use of Shuttle Radar Topography Mission (SRTM) data to identify fracture traces on Earth’s surface. Results were compared to the analysis method employed by RCD for 30 years, which relies on LANDSAT-TM Band 4. SRTM elevation models are expected to provide a direct representation of bedrock surface, while LANDSAT-TM Band 4 represents reflected near-infrared radiation as an indication of moisture content and is only a proxy for possible structures. Three areas in southwestern Pennsylvania were chosen for ground-truthing lineaments derived from both methods, following a series of desktop comparisons in six areas of the contiguous U.S. Field studies that identified numerous instances in which SRTM lineaments corresponded with joints at the projected location, and were oriented within 10° of joint strike, indicating that those SRTM lineaments represented the structural grain of the area. In some cases, lineaments were associated with individual joint zones. Photo-lineaments derived from the existing LANDSAT-TM methodology appear to offer a higher coincidence with expected trends of joints on a regional scale when performing the desktop comparisons, while field observations indicated that SRTM-derived lineaments had a higher association with individual geologic structures in the case study field area. It appears that both methods can identify the structural grain of an area, and that both tend to identify linear segments of valleys where erosion has preferentially occurred along joint zones or other structures.

Jul 1, 2023

By S. Meng, R. Jin, W. Hu

In alkaline pulp, galena is depressed by sodium carboxymethyl cellulose (NaCMC), while Cu(II) -activated sphalerite exhibits a high floatability so that satisfactory separation can be achieved. In addition to hydrogen bonding, chemical bonding of NaCMC with galena is confirmed by infrared (IR) spectra; only hydrogen bonding is involved between NaCMC and Cu(II)-activated sphalerite. It is also found that the greater the degree of substitution and polymerimtion of NaCMC, the stronger the depressive effect of NaCMC and that lower stirring speed favors the depression.

Jan 1, 1988

By John C. Morrisey, Harold M. Ray

With full production from the Casteel Mine in 1987 The Doe Run Company, a wholly owned subsidiary of the Fluor Corporation, encountered a significant increase of copper and iron to the Viburnum Mill. This major change of the lead, zinc, and copper metal ratios in the ore created circuit problems which adversely affected concentrate quality. Recognizing the problem, the company embarked on a metallurgical research program to include laboratory, pilot plant, and plant testing. The program developed an innovative copper prefloat process which both increased copper recovery and significantly improved concentrate quality. The process was tested and first operated at Doe Run's Brushy Creek Mill then installed at the Viburnum Mill in 1992. A brief history of development, plant operating data, and other potential applications for the patented processes will be described in the paper.

Jan 1, 1993

By Joseph M. Driscoll

After 30 years of successfully mining gold, Newmont Gold has temporarily ceased production from the original Carlin Pit. In late 1993, the Carlin East decline was driven and an extensive underground exploration program was started. Today, Newmont Gold produces refractory ore from the Carlin East Underground at the rate of 864 t/d (950 stpd). Annual production is more than 3.1 t (100,000 02). More than 70 underground miners will be employed during Carlin East's estimated six-year mine life. About 70% of the ore at Carlin East is mined by mechanized longhole stoping with delayed, cemented backfill. The remaining ore is mined by underhand drift and cemented fill methods.

Jan 1, 1997

By Michael A. Werner

"A Yieldable Structure for Use in Areas of High Rock Stress & Deformation." Rock stress of up to 9000 psi have been recorded in the mines of the Coeur d'Alene Mining district. Associated with these large stresses are rock fractures and deformation. In order to maintain openings required for mining, large wood preparation structures are constructed to provide access to the work areas for men and materials. These wood raise preparation structures are costly to construct and maintain. Therefore a steel-foam concrete structure was designed and proposed for testing which would be less costly to construct, require no maintainence and maintain its structural integrity while allowing up to 53 inches of wall rock deformation.

Jan 1, 1984

By S. Tan

In this paper, several commonly used computer truck dispatching criteria are evaluated. A computer-oriented truck dispatching and production simulator was developed to provide data for comprehensive cross comparison among the dispatching criteria. The definitions, primary considerations, characteristics, and performances of these dispatching criteria were investigated. From the simulation results, it was concluded that, in general, no one criterion can dominate all others. All basic dispatching criteria including minimizing truck waiting time, minimizing shovel waiting time, minimizing truck saturation, maximizing truck momentary productivity, or truck routes optimization provide a local optimal solution. To obtain a direct global optimization solution for this complex stochastic process does not appear to be likely. Therefore, the search for an optimal dispatching criterion that will fit all conditions may not be realistic. However, based on the simulation results of the mine operation, several dispatching criteria which have good potential to increase performance can be selected. It may be necessary to search for the best combination of these truck dispatching criteria for a given situation. For example, a truck flow measurement such as the truck clustering factor at shovels can be used as a switch parameter to change from one criterion to another. The values for the switch parameter at which actions should be taken to change the criterion can be established through simulation programs.

Jan 1, 1992

By R. Musu, J. A. E. Bell

P.T. Inco has constructed a smelter to produce 45 000 tonnes (49 500 tons) of nickel per year as a nickel matte from the lateritic ores of Sulawesi, Indonesia. The facilities include mines, five screening stations, two dryers, three novel reduction kilns, three electric furnaces, three top blown rotary converters, and associated infrastructure of port, towns and a hydroelectric generating station. The screening stations and converters are unique in the industry. The problems encountered in the construction and operation of this complex facility in remote Indonesia are described.

Jan 1, 1979

By R. Kramer, A. Habibi

A ventilation survey was conducted in an underground longwall trona mine. The mine is relatively shallow and categorized as a gassy mine. The ventilation system includes three intake and six exhaust shafts, and three surface axial fans ventilate the mine in a blowing configuration. Airflow quantity, pressure losses and air psychrometric characteristics were quantified, and the influence of moving cages and skips in the shaft examined. The benefits of utilizing high-accuracy digital pressure transducers and advanced psychrometers were seen when undertaking a “leapfrogging” survey to gather data needed to build a computer ventilation model. Two underground booster fans with VFDs are idle but available at the mine. The ventilation model was used to determine the optimal booster fan locations to decrease operating cost by reducing the load carried by the main fans. A leakage study was conducted to evaluate the effects on the system of additional pressure from a booster fan. The study finally prepares a future ventilation model for the next 15 years of mine operation and investigates the effect of proposed scenarios.

Jan 1, 2014

Coal has traditionally been an integral part of life in Kentucky. Coal mining produces a large part of revenue for the Commonwealth of Kentucky and provides a significant number of jobs to the residents of eastern (less in western) Kentucky. Recently, however, the coal industry of Kentucky has had to endure many hardships. The Clean Air Act set forth sulfur dioxide emission standards which have severely affected much of the coal mining industry in Kentucky, because much of the coal mined in Kentucky has a high sulfur content. In this paper, the background around the effects of Clean Air Act on the coal industry is introduced. The economic and social effects of the Clean Air Act on the Kentucky coal mining are addressed.

Jan 1, 1993

By Ralph W. Barbaro

This paper presents a cyclic queueing model which evaluates the productivity of a shovel-truck materials haulage system. For a cyclic queueing problem with exponentially distributed service times, a cyclic queueing model provides exact solutions in a fraction of the time that simulation takes to produce an approximate solution. The model is applied to an example problem, and the results are validated with simulation. Simulation is used to show that the assumptions of exponentially distributed service times and steady-state are not serious problems. A cyclic queueing model can be used to quickly obtain an accurate assessment of the productivity of a shovel-truck system.

Jan 1, 1986