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By H. J. van Antwerpen

AngloGold Ashanti operates the world`s deepest mine, Mponeng gold mine, in South Africa. A vast refrigeration and ventilation system provides acceptable working conditions 3800m below surface at 60°C rock temperature. In such a system, optimisation and assessment of modifications becomes very difficult. With that in mind, a research project was launched to determine whether recently developed system simulation technology can be applied to a mine as vast and complex as Mponeng. Using the techniques and methods as implemented in FLOWNEX software, it was indeed proven to be possible to do a mine-wide combined simulation of compressed air flow, ventilation air psychrometry and refrigeration water systems. Interactions between the various streams included heat transfer, pressure drop, evaporation and condensation. The simulation model was used in a parametric study to test various water flow and temperature operating points for the refrigeration system. It was found that, given current limitations, the mine refrigeration system is running fairly close to optimal but with some opportunities for improvement. The simulation model also provided useful insight for future changes or extensions to the system.

Feb 23, 2014

By Y. J. Wang

A critical path approach is presented for the problem of mine ventilation net- works where regulators and fans are employed to control the airflow distribution which is preassigned. The problem is a classic one which arises in mine ventilation planning. By identifying the analogy between the network for controlled flow and that for CPPI, the applications of the well known CPM technique to the ventilation network problem become straight- forward. The mathematical formulation of the problem is presented and the solutions are illustrated with examples. The effect of booster fans on the total air power consumed in a ventilation network are also discussed.

Jan 1, 1981

By Erik Westman, BEN WESTON, SETAREH GHAYCHI AFROUZ, KATHRYN DEHN

One of the most difficult challenges in underground mining is to forecast significant seismic events prior to their occurrence in order to support the safety of miners and to minimize damage to the underground operation. Passive seismic tomography is a tool to image the seismic velocity changes in a rockmass, which can potentially reveal the rockmass behavior before and after a significant seismic event. In this paper, the changes in seismic velocity of the rockmass before and after three major seismic events are investigated to determine whether there are identifiable precursory velocity changes associated with the major seismic events. Conventional mechanics imply that the induced stress at the hypocenter would continue increasing until failure, in the form of an induced seismic event, occurs. With passive seismic tomography we can image changes to the seismic wave velocity distribution within a rockmass and hence infer the changes to the induced stress near the hypocenter. This paper evaluates the hypothesis that induced stress at the hypocenter (as inferred by the p-wave velocity) increases until the seismic event occurs. In addition to analyzing p-wave velocity changes near the hypocenter, changes to the p-wave velocity at “zone centers” were also analyzed. These “zone centers” are regions within the rockmass that consistently have a p-wave velocity that is much higher than the average p-wave velocity for the rockmass. It is found that the p-wave velocity did not increase at any of the three hypocenters prior to the seismic event occurring, however the p-wave velocity did increase in the closest “zone center” for two of the three events.

Oct 12, 2020

By James L. Kelley

The Twin Buttes Mine, one of the more recently developed large copper mines in the United States, is in the Pima Mining District about 25 miles south of Tucson (Figure 1). Other copper producing mines in the district are the Esperanza-Sierrita mining operations, five miles to the southwest and the Pima and Mission Mines, seven miles to the north. Copper metal production from the Pima District in 1974 totaled 276,728 tons and the Twin Buttes Mine's share was 46,473 tons or about 17%.' The district's copper production was 31% of Arizona State's production and nearly 17% of the production from the United states in 1974. The Pima District thus ranks as one of the major copper producing areas in this country.

Jan 1, 1976

By S. L. Ducummon

Inactive underground mines now provide essential habitat for more than half of North America's 44 bat species, including some of the largest remaining populations. Thousands of abandoned mines have already been closed or are slated for safety closures, and many are destroyed during renewed mining in historic districts. The available evidence suggests that millions of bats have already been lost due to these closures. Bats are primary predators of night-flying insects that cost American farmers and foresters billions of dollars annually, therefore, threats to bat survival are cause for serious concern. Fortunately, mine closure methods exist that protect both bats and humans. Bat Conservation International (BCI) and the USDI-Bureau of Land Management founded the North American Bats and Mines Project to provide national leadership and coordination to minimize the loss of mine-roosting bats. This partnership has involved federal and state mine-land and wildlife managers and the mining industry. BCI has trained hundreds of mine-land and wildlife managers nationwide in mine assessment techniques for bats and bat-compatible closure methods, published technical information on bats and mine-land management, presented papers on bats and mines at national mining and wildlife conferences, and collaborated with numerous federal, state, and private partners to protect some of the most important mine-roosting bat populations. Our new mining industry initiative, Mining for Habitat, is designed to develop bat habitat conservation and enhancement plans for active mining operations. It includes the creation of cost-effective artificial underground bat roosts using surplus mining materials such as old mine-truck tires and culverts buried beneath waste rock.

Jan 1, 1997

By Adrian C. Dorenfeld

Concentradora "Dana Aida" (100 t/d capacity) was built in 1971-1972 to treat dumps and ores containing mixed oxide-sulfide copper-gold-silver minerals from two veins. The veins, Don Felipe and aria are about 150 m apart, but are distinctly different mineralogically. The deposit is near San Juan de Guadalupe, Durango. Mexico. All new process equipment was manufactured locally, in or near Torreon, Coahuila. Sampling, ore testing, flowsheet design, plant design, drawings purchasing, financing, etc. was planned and directed by two engineers. Construction was executed by local miners and common labor (largely agricultural). The paper presents detailed costs for equipment and construction. The subsequent breaking-in operation is discussed.

Jan 1, 1979

By Neal Retzer, Adam Bedell, Nick Cioffredi

The first wagon trail across Loveland Pass was built in 1869 thus starting the struggle between the Colorado Rockies and interstate travel. The 1st Pioneer Bore underneath Loveland Pass at the Continental Divide in Colorado was attempted between 1941 and 1943 and was abandoned due to ground conditions at the Loveland Fault. Construction on the nearby Eisenhower Tunnel began in 1967 and was completed in 1973. Numerous challenges associated with tunneling, including at 11,000 ft were overcome. The purpose of this paper is to summarize the history of investigation and construction challenges associated with the Eisenhower Tunnel to celebrate its 50th anniversary.

Jun 13, 2023

By Timothy O’Rourke, Karrie Buxton, Chris Lynagh, Daniel Dobbels, Frederick Vincent

The Doan Valley Storage Tunnel Project in Cleveland Ohio was constructed to control Combined Sewer Overflows (CSOs). It is a complex system of three tunnels ranging from 8.5 to 18 feet in diameter with a total length of about 2.3 miles that was put into operation in mid-2021. The project lies within and below the cultural, educational, and medical hub of Cleveland, which presented unique design and construction challenges. This paper provides a case history of the design and construction, with particular attention given to lessons learned in devising a large tunnel system that can carry both dry and wet weather flows constructed in rock with limited cover, within a flood plain area and vibrant urban center

Dec 1, 2022

By George Schmitt, Ted Dowey, Grant Millener, Sean McAndrew, Eric Jordan

The Rondout-West Branch Bypass Tunnel is being built to bypass a substantial leak in New York City’s primary water supply tunnel. The 13,500 foot long tunnel travels 600 feet under the Hudson River through the same troubled geology and high pressure water inflows that the original tunnel did in the 1940s. A Robbins TBM traversed this geology and built gasketed segments. Nine thousand two hundred feet of 16 foot diameter interliner was installed and backfilled within the segments. Finally, reinforced cast in place lining was placed. This paper addresses the challenges and the multi-tasking approach the contractor utilized.

Jun 13, 2021

By J. F. Childs

Montana consists of an Archean crystalline basement overlain by Proterozoic through Cenozoic sedimentary rocks. Igneous rocks range in age from Archean to Pleistocene; the most voluminous magmatism and volcanism occurred during the Late Cretaceous and early Tertiary. The state can be divided into three tectonic provinces whose deformational styles are a function of different bedrock responses to Late Cretaceous-early Eocene compressional tectonism. Several long-lived structural zones have been periodically reactivated since the Precambrian, and were the sites of recurrent magmatism. Regional gold distributions are strongly influenced by the tectonic provinces and structural zones. Lode gold systems in Montana occur in diverse geologic settings resulting from a complex interaction between structure, magmatism, and sedimentary depositional processes. Reserves or resources are known for 19 significant lode gold systems, and additional unannounced discoveries have been made recently. Mineralization ranges in age from Archean to Tertiary. The influence of long-lived structures is apparent at both the regional and deposit scale, and in some cases multiple mineralizing events have been superimposed upon one another. Most Montana gold systems have a direct spatial and genetic association with Late Cretaceous through Oligocene igneous rocks. However, the importance of sedimentary rocks and associated depositional processes should not be underestimated.

Jan 1, 1993

By A. Ghosh

Commonly used predictors of ground vibration from blasting, being linear in log-log plot, do not model the underlying physics of wave attenuation. Amplitude of the wave decays with distance due to geometrical spreading and inelastic attenuation producing a nonlinear carve in log-log scale. The nolinear decay of seismic waves has also been observed from non-explosive sources, such as, pile driving, drop hammer, traffic, etc. The improved predictors, by explicitly taking these two mechanisms into consideration, model the data trend extremely well at all distance ranges. Actual field data from different studies have been used to validate the improved models.

Jan 1, 1991

By John C. Kleiber

From time to time since the initial installation of an experimental flotation section in 1940 (reference A), Permanente Cement Company has made efforts to beneficiate the low-grade limestone fraction which occurs in its deposit at Permanente, California, The encouraging results outlined in this paper are the result of Permanente's latest effort. This paper discusses the factors governing the selection of the flowsheet with particular reference to marketability of the sand tailing by-product. The process flow is outlined in detail, and operating statistics of the plant are presented. Finally, the problems encountered in the operation of Permanente's beneficiation plant are discussed as well as solutions sought and found.

Jan 1, 1964

By J. Larsson

In the pursuit of increased safety the mining industry has worked to develop systems for remote control and autonomous operation of both stationary and mobile equipment. This paper reports on a newly developed system for teleoperation and autonomous tramming of LHD (Load-Haul-Dump) mining vehicles that not only increases the safety of the operators, but also has the potential to increase productivity.

Jan 1, 2010

By Siqing Liu

A low-grade cassiterite-magnetite ore from Sichuan province, China, is finely disseminated, assaying 0.39% Sn and 23.20% Fe, respectively. Mineralogy studies show that the fine-sized cassiterite is mainly disseminated in iron minerals and gangue. Moreover, the embedded size of cassiterite is very fine and must be ground to -0.01 mm to achieve a degree of liberation of about 90%. Therefore, fine grinding needs to be conducted to get a high quality tin concentrate and a great loss of tin cannot be avoided when treating the ore by gravity concentration. Based on the above facts, a two-stage separation, with a low intensity magnetic separator and a shaking table, was selected to test the ore. Compared with other similar plants, a relatively good separation has been achieved. Three acceptable products for smelters were obtained as following: iron concentrate assaying 61.69% Fe with a recovery of 75.09%, tin concentrate assaying 27.21% Sn with a recovery of 56.97% and a sulfur concentrate assaying 40.86% S with a recovery of 32.03%, respectively.

Jan 1, 2011

By Jon Ike Isaacson, Michael Miller, Jarek Trela

Despite reef structures being relatively common in carbonate rocks around the world, tunneling experience in reefs is extremely rare. Impacts and risks associated with reef tunneling through these geologic features were also relatively unknown. A new reef was encountered during construction of the Lower Pogues Run Tunnel in Indianapolis, exposed over 5,000 linear feet along the alignment, resulting in adverse impacts on construction. Analysis of investigation data and construction from this encounter provide insight into the identification and characterization of reefs along tunnel alignments as well as the potential impacts on construction for future tunneling within reef structures.

Jun 23, 2024

Two new inorganic-organic hybrid polymers, Al(OH)3-polyacrylamide (Al(OH)3-PAM) and Mg(OH)2-polyacrylamide (Mg(OH)2-PAM) were synthesized and successfully applied for the treatment of oil sand tailings. The results indicate that both Mg(OH)2-PAM and Al(OH)3-PAM were unaffected by the change in pH, and could be applied to oil sand tailings with varying sand-to-fine ratio (SFR). The optimum dosages for the Mg(OH)2-PAM and Al(OH)3-PAM were about 330 g/ton and 650 g/ton, respectively for SFR 3.75. The flocculated oil sand tailings dewater quickly producing 66-68% solids. The flocculated tailings produced similar filtration rate before and after shear. Mg(OH)2-PAM treated oil sand tailings produced twice the filtration rates (220 ml/min) compared with Al(OH)3-PAM. This study clearly indicates that Mg(OH)2-PAM and Al(OH)3-PAM is a viable solution while decreasing the mass-production of tailings and increasing the rate of water-recycle.

Jan 1, 2012

By Jr. Schnakenberg

The automation (robotization) of coal mining activities at the face offers improvements in worker safety and productivity. The evolutionary introduction of autonomous, intelligent robotic machines to perform the most hazardous tasks may become a reality within the next 10 years. The U.S. Bureau of Mines Robotics and Automation research program is aggressively pursuing the development of the enabling technology necessary to achieve this goal. This program consists of both core and applications research, each focused on the fundamental issues of robotic technology. In the short term, the research is directed specifically to the robotization of present-day underground equipment and is being performed in a manner that can make incremental improvements in safety and productivity. The long-term goal is the development of intelligent autonomous mining systems.

Jan 1, 1990

By A. S. Atkins

The interest in the use of micro- organisms in the leaching of sulphide minerals has been traditionally exploited as a scavenger process for the recovery of valuable metal by- products from waste ore dumps. Environmental concern on sulphur emission from conventional pyrometallurgical plants together with the cost of stack cleaning systems to comply with legislative control also indicate baccerial leaching to offer a low cost treatment for the processing of sulphide minerals. The paper describes the effect and limits of relatively coarse particles on the complete leaching of pyrite and its importance to the practical application in dump leaching operations of sulphide minerals. It has also been demonstrated that static leaching techniques have encouraging economic potential for process plant operations compared with agitated leaching systems.

Jan 1, 1984

By M. N. Nabighian

Utilization of x-ray diffraction data for mineral identification has been well documented and accepted as an analytical tool in industrial and research organizations. However, the search for new methods to minimize errors affecting measured reflection intensities is being carried out by all concerned. Recent application of computer capability has greatly reduced the time required in handling data for mineral analysis and has increased the capability of accepting more data for greater precision. The purpose of this communication is (1) to describe the concept of cross-power in XRD analysis, and (2) to show that direct comparison analysis for multiphase systems has improved analytical accuracy when all available x-ray diffraction data are used in conjunction with high speed data processing by computer.

Jan 1, 1972

By M. E. Ryan, C. L. Hoebbel, E. J. Haas

DISCLAIMER The findings and conclusions in this paper are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of any company or product does not imply endorsement does not constitute endorsement by NIOSH. ABSTRACT It has been suggested that effective disaster prevention and response in mining requires that elements of emergency management be incorporated into everyday operations, planning, and decision-making, much in the same way that the industry approaches routine risk management. Since Congress passed the MINER Act in 2006, the newly mandated structural and technological advancements in mine emergency response preparation have been made and are apparent, but measureable improvement in mineworker emergency preparedness is difficult to ascertain. To begin exploring whether measurable indicators of mine workforce preparedness can or should be addressed within a risk management framework, NIOSH researchers examined the datasets from two separate research efforts—one which measured the organizational safety climate and self-reported safety performance, and the other which measured individuals’ perceptions of their own self-escape competency. INTRODUCTION In response to the mine disasters in 2006, the United States Congress passed the Mine Improvement and New Emergency Response Act (MINER Act), which strengthened existing regulations [30 CFR, Part 48] and introduced new provisions to improve mine emergency response. Since that time, new technological and structural features, such as mandated redundant communication systems, personnel tracking systems, and lifelines in primary and secondary escapeways, have been installed in underground coal mines across the country. Additionally, mine operators are required to develop emergency response plans, provide adequate supplies of breathable air throughout the mine, provide more frequent and realistic expectations training, and are required to immediately notify the Mine Safety and Health Administration (MSHA) in the event of an accident. While the structural and technological advancements in emergency preparedness are readily observable and easily measured, levels of individual mineworker preparedness remain difficult to assess. There is a general consensus that deficiencies in competence in the non-routine tasks required for individual miners to effectively respond to a mine emergency likely remain (e.g., National Research Council [NRC], 2013), and NIOSH research continues address this concern (Haas, et al., 2015; Hoebbel et al., 2018). To maximize an operation’s capacity to effectively prevent disasters and/or respond to emergency events, it has been suggested that individual and emergency management efforts be incorporated into everyday operations, planning, and decision-making in much the same way organizations manage routine risks to health and safety (Haddow et al., 2017). To the authors’ knowledge, the mindful intersection of routine risk management policies and practices and emergency prevention and response readiness have yet to be empirically studied within the mining industry.

Jan 1, 2019