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By Edward S. Frohling

Va a ser discutida la información que se requiere para un estudio preliminar de viabilidad y la información adicional que se requiere para el estudio final de viabilidad de un nuevo depósito de mineral. El estudio preliminar de viabilidad se realiza con muy poca información y con un mínimo coste para el propietario. Sin embargo, el diseno del informe preliminar es similar al utilizado para el informe final. En este momento, se supone que el resultado del estudio preliminar es favorable y el propietario autoriza el estudio final de viabilidad a una compañía de ingeniería. Se describirá el tipo de organización para completar el estudio final de viabilidad. El informe final incluirá toda la información y datos relativos al nuevo depósito de mineral. La información presentada debe ser entendida lo mismo por el personal financiero que por el técnico.

Jan 1, 1982

By J. L. Sloughfy

The size distribution and mechanical strength of the iron ore pellet burden are important parameters in determining the efficiency of the blast furnace. From the very outset, the guiding principle of our pellet quality improvement program was that these parameters are also the key to improving productivity and cost control at the pellet plant. Recognizing the need for improved blast furnace burdens and for higher productivity and lower costs at the pellet plant, Carol Lake operators, in conjunction with the IOC Pellet Quality Committee, established the following goals for the improvement of Carol pellets: [ ]

Jan 1, 1981

By J. V. Belke

There are many aspects of a grinding mill supply and installation that can result in the mill not operating as intended, resulting in unplanned shutdowns, poor reliability and headaches for all concerned. One of the largest aspects, both in criticality and physical mass, is the mill foundation; if not properly specified, designed and constructed the mill operation will be compromised. The mill foundation starts with the design specification and loading diagram supplied by the mill builder. The importance of understanding these documents and how to apply them is critical for the start of any mill project. When designing mills with a GMD the foundation must be properly modeled to ensure that all interactions of the mill and motor structures, foundation and subsurface strata behave in the intended fashion. All of the previous efforts can be laid to waste if the construction of the mill foundation is poorly handled. Mill foundations are typically the most massive concrete structure at a processing plant and can easily cause nightmares for inexperienced contactors. This paper explores some of the more important facets along the lifecycle of the grinding mill foundation.

Feb 23, 2014

By D. Nilsson

This paper demonstrates the importance of including a discount rate in the determination of the optimum final' depth of an open pit. Without a proper discount rate, a pit will probably end up too deep. Another consideration is future underground mining. If underground mining is profitable, the pit may need to be shallower. Of all of the investments needed, only mining equipment and the underground mine should be included, and amortization and depreciation should not he included in the study.

Jan 1, 1997

The initiation of a panel cave is an extremely important and infrequent event in the life of a large underground caving operation. A new cave was initiated at the Henderson Mine in 1991, 15 years after its first cave had been developed in 1976. The original cave was started after a half billion dollars had been invested in the development of the mine, mill and 23 km haulage system. Many things had changed since 1976, the most significant of these being much lower realizations for molybdenum. In 1976 the high demand for molybdenum and uncertainty of caving characteristics, formed the basis for a very conservative cave initiation sequence with miles of boundary weakening and inspection drifting. In 1991 the highly competitive molybdenum market in conjunction with 15 years of caving experience made for a very different mining climate.

Jan 1, 1994

By J. L. Francke

This paper describes the practices and methods used in a study of Time Domain Reflectometry (TDR) as an inexpensive deformation monitoring tool in underground excavations at the Waste Isolation Pilot Plant (WIPP). The WIPP is being developed near Carlsbad, New Mexico, for the disposal of transuranic nuclear wastes in bedded salt 655 m (2 150 ft) below the surface. Data collected from WIPP geomechanical monitoring are used to characterize conditions, confirm design assumptions, and understand and predict the performance of the deep salt excavation. The geomechanical monitoring program encompasses numerous geomechanical monitoring techniques ranging from inspection of observation boreholes to advanced radar surveys. In 1989 TDR was introduced as a monitoring tool with the installation of 12.7 mm (0.5 in) diameter TDR cables in the underground excavations. In 1993, a new TDR system was installed in a separate location. Based on experience with the previous installation, enhancements were implemented into the new TDR system that: 1.) extended the period of performance by increasing cable diameter to 22.2 mm (0.875 in), 2.) increased accuracy in locating areas of deformation by aligning cables with nearby observation boreholes, and 3.) improved data acquisition and analyses using a standard laptop computer, eliminating the chart recorder previously used. In summary, the results of a correlation between the TDR signatures to nearby observation boreholes and geomechanical instrumentation will be presented.

Jan 1, 1996

By T. J. Lutz, J. L. Carr, J. A. Yonkey, C. C. Jobes

"Since 1984, the date of the first recorded fatality involving a remote controlled continuous mining machine, 38 miners in the United States have been killed when they were struck by a continuous mining machine. Proximity detection is a valuable tool for preventing fatalities, and the use of these systems is expected to significantly improve safety. Proximity detection provides a means to prevent accidents like these. Researchers at the National Institute for Occupational Safety and Health (NIOSH) conducted a series of underground tests to evaluate the accuracy and repeatability of proximity detection systems under a number of conditions such as varying the orientation and height of the personal wearable device (PWD), moving the PWD close to the trailing cable, and activating the machine’s mining mode. At the 2014 SME Annual Meeting, results from tests on first-generation proximity detection systems were presented. This paper will provide results from the similar tests performed with second-generation systems. The results show that performance has improved. For example, the negative impact of PWD orientation and the trailing cable has been reduced. However, some inconsistencies remain. Notably, performance changes dramatically when mining mode is activated. INTRODUCTION Since 1984 there have been 38 fatalities involving striking and pinning of the operator and other workers by the continuous mining machine (CMM) [1]. In August 2011, the Mine Safety and Health Administration (MSHA) published a proposed regulation that would require proximity detection systems on all continuous mining machines except full-face machines [2]. Proximity detection systems are designed to stop machine motion to protect miners from striking/pinning hazards. Several MSHA-approved proximity detection systems are commercially available. MSHA estimates that of the 38 fatal striking and pinning accidents that have occurred since 1984 involving CMMs, the use of proximity detection could have been a preventative factor in at least 28 cases [1]. Furthermore, MSHA estimates that proximity detection could prevent 20% of all deaths throughout the industry [3]. NIOSH researchers have been involved in the development and testing of proximity detection technology since creating the HASARD system [4] and have recently conducted research intended to develop more advanced proximity detection technology for CMMs [5,6,7,8]. In addition, NIOSH has also conducted research investigating how the signals of a proximity detection system propagate [9,10] and have developed a novel method for determining the location of a personal wearable device (PWD) relative to the magnetic field generators [11,12]."

Jan 1, 2015

By C. T. Aimone-Martin

Time-domain reflectometry (TDR) laboratory experiments have been conducted using cylindrical salt cores from the Waste Isolation Pilot Project (WIPP). TDR has been used as an instrumentation technique to quantify the type and magnitude of rock mass deformation. Laboratory shear and tensile tests were conducted to calibrate measured deformation versus changes in reflected waveforms. Coaxial cables grouted within rock cores were crimped to produce localized reference defects. The evaluation of waveform characteristics produced during rock deformation experiments shows a good correlation of cable response to both shear and extension of the salt

Jan 1, 1994

By James J. Brady, Kenneth L. Faught, Chadi El Mohtar, Chaoshi Hu

"During construction of a 9.5-ft. diameter sanitary sewer tunnel, the City of Edmonton encountered a large pocket of flowing sand that flooded their TBM and caused significant surface subsidence, stopping further tunneling by the TBM through this zone. A unique collaborative effort ensued between the authors representing the city, consulting engineers and academic researchers to develop the optimal strategy for grouting the problematic soils. The site has a layer of very find sand between 20 and 30 ft. in depth with fines contents ranging from 5% to more than 40%. The collaboration extended from requesting additional site investigation efforts to shipping samples to the UT-Austin laboratories for grout testing plus ground and grouting characterization tests resulting in field recommendations for a full scale ground improvement program. New research information on the grouting of fine sands along with a collaborative framework for the design of in-situ grouting projects are the key topics presented. INTRODUCTION Encountering a large unexpected pocket of flowing sand with an open-faced TBM while excavating a tunnel below the groundwater table is never a good thing. This was certainly true for the City of Edmonton when one of their Lovat TBM’s became inundated by flowing sand while excavating the 9.5-ft. diameter Millwoods Double Barrel Replacement Tunnel in September 2013. However, since the City of Edmonton self-performed this work, a rare situation existed where the site could be investigated objectively, without the prejudice of contending parties selectively influencing how information was gathered and presented, to accurately examine site conditions with a goal of identifying the best remediation measures."

Jan 1, 2016

"The Industrial Comminution Efficiency (ICE) working group, part of the Global Mining Standards and Guidelines Group (GMSG) has engaged a large number of industry professionals representing mining companies, equipment vendors, consultants and metallurgical laboratories with interests and capabilities in the comminution field. These participants have collaborated to develop three guidelines for the assessment of the efficiency of mineral comminution circuits. Two of these guidelines deal specifically with power based modelling techniques to quantify energy efficiency using widely practiced techniques, those developed by Bond (1961), Rowland and McIvor (2009), and Morrell (2009). The third guideline deals with the sampling and surveying of grinding circuits as is required to provide the necessary information, at appropriate quality, to furnish the efficiency analysis promoted by the first two guidelines. This preprint will focus on the Guideline on Methods to Survey and Sample Grinding Circuits, which is currently in the final stages of peer review and finalization by the GMSG. INTRODUCTION It is important to make a clear distinction on the scope of work of the GMSG guideline for sampling grinding circuits. Many mineral processing practitioners are familiar with the sampling and surveying of comminution circuits, in particular grinding circuits, for performance diagnosis and the identification of optimization potential. These surveys often provide information for population balance modelling of individual comminution and classification unit processes, and as a result require a large amount of information to calibrate and validate the unit models. As a result these surveys are labour intensive, somewhat expensive depending on internal capabilities of the mine site or company, and have a long time span from initial planning to final reporting. They also require a high level of expertise to process the survey data, simulate the circuit and make sensible recommendations on follow up actions. As a result of these factors full grinding circuit surveys are not a common occurrence at a large number of facilities, and several years may pass before follow up surveys are conducted. In the ensuing gap between surveys, the efficiency of the grinding circuit must often be taken on faith, and this is considered an unacceptable lapse in an environment of strained natural resources and low commodity prices. To support the rapid and productive energy efficiency analysis being promoted by the ICE working group, a much simplified survey and analysis process is required. The process reflected in the GMSG guideline is indeed more conducive to frequent analysis, at a skill level that is well within the capabilities of the average plant metallurgist. As a result it becomes feasible to conduct mini-surveys of plant performance, which can be used to quickly and precisely diagnose the high level impact of process changes. It can also be manipulated by experienced practitioner to provide sufficient information for modelling of the circuit to estimate the impact of process changes, supporting an initial rate and rank exercise to focus plant optimization efforts."

Jan 1, 2016

By J. C. Stankus

In this paper, an innovative concept in longwall tailgate support is discussed. This new concept utilizes a new high capacity roof truss system in lieu of conventional wooden crib block. The first field test was conducted at Bailey Mine and was very successful. Similar tests have been installed in other mines and seams. An extensive instrumentation plan was designed and implemented in the truss test area. The test data has shown that the dynamic roof truss system effectively controls the various abutment pressures caused by longwall mining thus maintaining a stable tailgate entry.

Jan 1, 1995

By J. M. Bray, R. R. H. Cohen, P. Kiousis, S. R. Al-Abed

"INTRODUCTION Conventional tailing storage and management practices typically utilize engineered facilities, such as ring dikes and valley impoundments. To reduce the environmental costs associated with disposing of mine wastes in tailing storage facilities (TSFs), several beneficial re-use strategies have been developed over the years. For example, thickened tailings have been used for paste backfill. It is common for tails to comprise up to 60% of the material’s total weight and it has been estimated that TSF volumes can be reduced by 60% when using this strategy, (Benzaazoua, et al. 2004). Other beneficial re-use strategies have produced unpaved temporary access roads, hot and cold asphalt, chip seals, self-compacting concrete, and golf course sand traps. This project sampled mine tailings from two different TSFs in Colorado and produced structural concrete that could potentially be used for commercial foundations, sidewalks, and paved roads. The tailings were substituted for the fine aggregates typically found in conventional concrete. The two main objectives of this study were to investigate the structural integrity of the produced concrete samples and the leaching of heavy metals from the resulting concrete. The ratio of tailings to fine aggregate (T/FA) was carefully studied to find if there was a correlation between the substitution rate and the structural integrity. The potential maximum substitution rate was also investigated for the produced concrete specimens. The potential of leaching mining impacted water (MIW) was evaluated by comparing the leachability of the raw mine tailings to the encapsulated tailings by using standard shake extraction prediction tests. MATERIAL AND METHODS Materials The four components that make up the concrete mix design for this project are: cement, coarse aggregate (gravel), fine aggregate (sand and mine tailings), and water. The type I/II ordinary Portland cement (OPC), gravel, and sand came from local cement and concrete companies in Denver, Colorado. Mine tailings were collected from two different TSFs in the Rocky Mountain Region, where Pride of the West TSF in Silverton, CO will be denoted as Site A. The primary metals of interest at the mill site are gold, silver, lead, copper, and zinc. The location of Site B will not be mentioned in this report due to confidentiality agreements with the mining company"

Jan 1, 2016

By M. Raffaldi, J. Johnson, M. Stepan, D. Benton

"The Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD), is continuing its High-Energy High-Displacement (HEHD) testing of field-scale shotcrete panels. A test program was developed to determine the relationship between applied force, displacement, and energy for both unreinforced and reinforced shotcrete panels. Reinforcement options consisted of synthetic macro-fibers, sprayed polyurea liners, chain-link fence, welded-wire mesh, and combinations of these products. During testing, photogrammetry was used to measure the geometric changes of the panels, including volume changes and panel cracking. These measurements were correlated with the load and displacement data, allowing visual observation to be related to the applied force and displacement. The test results provide a comparison of the mechanical performance of the various panel types and can be used by the practicing engineer to evaluate installed support based on visual observation of cracking and deformation. Visual assessment of the loading cycle and strength capacity of shotcrete in underground excavations will improve mine safety by providing a means to quantify the stability of installed shotcrete support. INTRODUCTION The National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research (OMSHR), Spokane Mining Research Division (SMRD) is continuing research on the behavior of shotcrete when used as the surface support component in mining ground support systems. Ground control safety often depends on supporting, or at least containing, the ground between the rockbolts. Shotcrete and mesh, in various combinations and with other components, are often used to accomplish this (see Figure 1). Maintaining support pressure during ground deformation is key to the performance of these systems, and to ensuring miner safety. However, the toughness of a ground support system–the ability to maintain strength over large deformations–is difficult to quantify. Researchers at SMRD have responded to this deficiency by designing a full-scale test device, described previously by Martin et al. [2015a], and beginning a testing program to assess the behavior of shotcrete surface support reinforced with a variety of products including: fibers, chain-link mesh, welded-wire mesh, spray-on polyurea liners, and combinations of these products. This paper presents the findings of these tests."

Jan 1, 2016

By R. Bishop, J. Baggett, J. Monsalve, J. Hole, N. Ripepi, A. Abassi

This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Issues include water inrush, structural instability, and engineering uncertainty in these environments. Coupled with the fracturing prevalent in folded sedimentary rocks, karsts are complex and challenging ground control risks. Traditional methods of predicting karst locations, such as probe drilling, are impeded by the inconsistent spatial distribution and variable sizes of the features. Ground penetrating radar (GPR) is a geophysical technique that transmits radio waves into a medium and subsequently detects reflected waves via a receiver. The travel time and energy of received signals are then processed and interpreted. The difference in material properties between limestone and open karsts causes strong reflections. GPR is frequently used as a geophysical surveying technique in several industries, however there is a lack of published research on underground mining GPR applications. The purpose of this work is to prove the viability of GPR in underground stone mines for karst detection, and to discuss the importance of karst detection ahead of mining. INTRODUCTION The Mine Safety and Health Administration (MSHA) currently lists 116 active underground stone mines in the United States, the vast majority of which extract limestone for crushed stone products. These limestone mines have the potential to encounter karst voids at some point in their operation, as most karstic regions of the United States develop in limestone rock masses (Kuniansky, Weary, & Kaufmann, 2016). Karsts, the cavities formed by the dissolution of carbonate rock, have long plagued the mining and tunneling industries, as well as been a hindrance on the Earth’s surface, producing sinkholes and ruining otherwise valuable land for construction and public use. The impact of karsts on the Gavarres tunnel in Spain is well documented by Alija et al; constant instability conditions, material spills into the tunnel, and unexpected cavities seriously delayed the project deadlines and “were not foreseen in the design” (Alija, Torrijo, & Qunita-Ferreira, 2013). At the water supply project in Sohngua River, China, Bin et al detail the presence of both water and sediment filled karsts which are sources of disastrous conditions at this tunnel (Bin, et al., 2017). A hydrological tunnel in Lebanon encountered numerous massive karsts in the tunneling path which required remediation via friction anchors, rockbolts, welded wire fabric, channel steel arch segments, invert steel beams, and shotcrete (Leech, Jaoude, & Ghanem, 2008). From a design standpoint, rock mass classification schemes, such as the RMR from Bieniawski and the Q-system from Barton, are not able to represent the true nature of a karstified carbonate rock mass, and therefore complex case-by-case analyses of underground conditions are necessary (Andriani & Parise, 2017).

Jan 1, 2019

By Arthur G. Strassburger

INTRODUCTION High in the Sierra Nevada Mountains of California, some 50 airline miles (80 km) northeast of Fresno, and near the John Muir Wilderness and Kings Canyon National Park, a large underground hydroelectric project is under construction. Pacific Gas & Electric (PG&E) Company's 1,125 MW Helms Pumped Storage Project exhibits a number of impressive statistics, unusual features, and other characteristics of interest to the tunneling or power plant designer and construction contractor. The most significant underground facilities include almost 20,000 ft (6,096 m) of 27-ft (8.2 m) diam concrete-lined pressure tunnel; 3,700 ft (1,128 m) of access tunnel; 1,600 ft (488 m) of steel-lined high-pressure conduit, 2 major underground chambers more than 1,000 ft (305 m) below ground; 3 deep vertical shafts, and one steep inclined shaft. Maximum static pressures within the conduits range from 200 ft (61 m) to 1,744 ft (532 m), with hydraulic transients that increase pressure to 2,500 ft (762 m). The purpose of these underground works is to provide 475,000 hp (354,350 KW) of water power to each of the 3 reversible pump-turbines, each connected to a 375 MW generator motor. The units, rated at 1,744 ft (532 m) maximum static head, are among the world's front-runners, considering the size-head combination. The Helms Project develops the existing power drop between two of PG&E's reservoirs, Courtright Lake and Lake Wishon. These reservoirs are retained by two concrete-faced rockfill dams completed in 1958, each storing approximately 125,000 acre ft (154 x 106 m3) of water. Although the project is intended to operate on a typical

Jan 1, 1981

By Joseph W. Leonard

By combining statistical methods with specialized coal technology, novel and widely applicable procedures are developed which are useful for making important decisions based on coal seam structure. By analyzing such properties as ash in visual coal types of seam cross sections and by processing the ash data to 100 gram increments of coal ranging from the top to the bottom of the seam, intraseam comparisons between data populations of samples from a given seam and a reference seam can be made. Moreover, illustrations are presented for estimating the number of drill cores required to purchase a specified level of sampling accuracy together with procedures for determining the probability that different coal scan cross sections are not unlike and by inference are therefore comparable. Such comparisons can be valuable when making important, costly and long prevaling decisions involving coal exploration, mining, preparation and utilization.

Jan 1, 1969

By R. J. McGregor, Deepak Malhotra

Engineers frequently encounter situations where decisions that are counterintuitive to the logically trained engineering mind are made because of other influences, whether they be financial, social, cultural, or environmental. Such influences can overrule the "logical" decision-making process. The aim of this book is to explore some of the nontechnical issues, which most engineers don't learn about in school, that can have a major impact in the mining industry. This chapter gives a brief overview of this volume and introduces the topics that will be addressed.

Jan 1, 2001

By B. L. Bessinger

Because of a, work stoppage at the Carlsbad plant, IMC faced the challenge of operating a 24-hour-a-day mine and plant with inexperienced maintenance and production crews. This is an underground mining operation, using the room-and-pillar mining- method. The mine was entirely, mechanized with conventional equipment, was hoisting an average of 13,539 tons off ore per 24 hours, and employed a, mine maintenance group of 100 men. The 100-man, mine maintenance group was equally divided between mechanics and electricians. In re-forming this maintenance group, two main objectives were to be achieved (1) a general upgrading off the intelligence level; and (2) the elimination of craft lines for greater flexibility.

Jan 1, 1966

By W. L. Price

Since first introduced in the United States in 1964, rail mounted bucket wheel stacker-reclaimers have gained wide acceptance by users. The coal burning power plant group has adopted this new storage tool most quickly. The actual history is traced in this area in some detail. Installations in phosphate and steel mill ore storage and a listing of present users are included.

Jan 1, 1969

By J. Fisher, M. Barish

Over the past several years, Somerset International has successfully installed over 20 patented Sub325® Fine Coal Recovery Systems in the United States, Australia, Canada and Russia. These installations recover between 5 TPH and 40 TPH for the host sites. In addition to the increased revenue from the direct recovery of a recirculating load (Screen Bowl “Insurance”, Direct Recovery vs. Indirect Recovery via Recycle, CPSA 2020), host sites have seen benefits ranging from improved operation of refuse equipment to a reduction in the solids content of the refuse streams. As Somerset has improved ultra-fine coal recovery through the introduction of Sub325® Effluent Flotation and, most recently, the Sub325® Effluent Settler™, the amount of coal that has been recovered from these systems has increased by up to as much as 25%. Many host sites have taken a sense of ownership in the Somerset system and consider it to be a critical circuit in the overall optimal performance of the plant. In the past year, Somerset has taken the initiative to expand upon the capabilities of the Sub325® Fine Coal Recovery System, primarily the Sub325® Solid Bowl Centrifuge, to include Refuse Tailings Dewatering to allow for co-mingled refuse disposal. As slurry ponds and boreholes are becoming difficult to impossible to permit and operate, there is a need for a reliable, low-maintenance, continuous operation that can produce a handleable refuse cake. Refuse tailings disposal applications are by no means limited to coal plants and impoundments. Somerset has successfully tested at iron ore and phosphate locations throughout the world and have begun commercial installations. The ability to dewater -325 mesh material, whether it be coal, coal refuse, iron ore tailings, or something else, is a vital piece of processing capability for the continued production of mining operations across the globe. This paper highlights the success that Somerset has had in the coal industry worldwide as well as the initial successes with phosphate, iron ore, and copper tailings (patent pending).

Mar 2, 2022