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By C. Pritchard

John Marks said in his acceptance of the Hartman Award in 2008 ? ?I guess that without the occasional complaint, your mine is probably over-ventilated? (Marks, 2008). Miners are seldom in this situation and often spend much of the time trying to find enough air to keep the operation running. With examination there are some things that can be done to make the best use of ventilation systems. Should there be surplus air, in which some of these options may result - financial and other benefits can be obtained. Some of the issues mine operators have needed to address recently are increased airflow requirements to dilute diesel particulates in metal and non-metal mines. Also, operations are faced with demands from reserves that are deeper, hotter and further away from fans and shafts, not to mention increased production demands. Mine ventilation air is a costly commodity, especially by the time it has been heated or cooled and moved to the bottom of the shaft and through the mine airways. Most of the options presented in this paper are useful for metal non-metal operations but some may be applicable to coal too. OPTIONS FOR IMPROVEMENT Some of the areas to be addressed are shop ventilation methods, auxiliary equipment areas, dedicated intakes and returns, optimizing development, examination of mine airway utilization and alternative ventilation methods. UNDERGROUND SHOPS First, examine what is being done with the underground shop air. If it is being coursed directly to the returns there may be some potential to better utilize this, in most cases, relatively contaminant free air. Research the legal options for ventilating mine shops. MSHA regulations in 30CFR 57.4761 (1) allow the following options: To confine or prevent the spread of toxic gases from a fire originating in an underground shop where maintenance work is routinely done on mobile equipment, one of the following measures shall be taken: use of control doors or bulkheads, routing of the mine shop air directly to an exhaust system, reversal of mechanical ventilation, or use of an automatic fire suppression system in conjunction with an alternate escape route. The alternative used shall at all times provide at least the same degree of safety as control doors or bulkheads. Discussion This regulation gives some operators flexibility in ventilating underground shop facilities. If shop air is to be coursed through the work area, and then directly to the mine return, the question should be asked ? is the quality of air good enough to be reused in the mine, and if so, what are the risks? Can the risks be accommodated and managed to accomplish the change? If so, a considerable increase in mine level airflow could be attained by reusing shop air. Clearly, regulations are a minimum standard, and can be exceeded. Metal non-metal mine regulations are not as specific as coal due to the multitude of different mining methods and conditions utilized. Risks must be thoroughly examined and addressed to assure a safe environment. Issues Determine what contaminants are being produced in the work area ? welding fumes, diesel exhaust, paint fumes, chemicals and solvents, etc. Survey the area and determine exposures. MSHA requires exposure monitoring in 30 CFR 57.5002 (1) of dust, gasses mists and fumes to assure air quality is being met. Perform surveys and examine existing data to quantify personal and area concentrations of contaminants. Often there is adequate circulation such that exposure levels in shop work areas are low. After sending shop air back into the system any contaminants would be further lowered by dilution with other mine intake air downstream. Look at the shop work schedule. If only on day shift, the other two shifts and possibly weekends have no activity or source of contamination to affect the ventilation system. The worst case planning scenario would be a shop fire. Study and simulate how this would affect the mine and shop area. MSHA regulations require an escape route and a fire suppression system be installed and maintained as follows in 30 CFR 57.4671 (1): (d) Automatic fire suppression system and escape route. If used as an alternative, the automatic fire suppression system and alternate escape route shall meet the following requirements: (1) The suppression system shall be? (d)(1)(i) Located in the shop area; (d)(1)(ii) The appropriate size and type for the particular fire hazards involved; and (d)(1)(iii) Inspected at weekly intervals and properly maintained. (2) The escape route shall bypass the shop area so that the route will not be affected by a fire in the shop area. Case Study In an underground room and pillar mine, active mine workings were advancing further away from the mine shaft with deteriorated returns and leakage having a negative effect on ventilation airflows to the face. Mine level airflows were 236 m3/s (500,000 cfm) and shop airflows were 24 m3/s (50,000 cfm) (see Figure 1A). No additional capacity was available at the main surface fan. A solution was to utilize the shop air then send it to the mine areas instead of directly to the return. Considerable information on shop air quality and exposures from many years of operation was examined and no negative data was discovered. A risk analysis determined that moving forward with a shop air reuse program was desirable. A plan was developed, analyzed and decision to proceed approved by mine management. The change was simulated on the computer with the USBM/MTU MFire program before being implemented. This included utilizing fire scenarios to examine potential exposures to inby mining sections and plan escape routes. A monitoring system was designed and installed in cooperation with the US Bureau of Mines to monitor carbon monoxide

Jan 1, 2009

By G C. Snedden

Tandem row stator arrangements are common in the last stage of multirow, gas turbine compressors. Tandem row stators, or stator and de-swirler vane combinations are used to relieve the loading on the stator but ensure axial flow leaving the compressor. In this paper a standard 40” (1016 mm) ventilation fan in the Air Blow Fan’s range is modified to utilise the plate support struts on the barrel to relieve the aerodynamic loading on the aerofoil stator. Performance maps for both versions of the fan were generated using computational fluid dynamics and are compared across a wide range of rotor setting angles showing a clear advantage of approximately 2 per cent in efficiency for the tandem blade design. In addition, the area of high efficiency that represents the practically usable area of the map extends over a greater area in terms of flow rate and total pressure rise.

Oct 12, 2022

By K J ROSENGREN

Underground rock mechanics was initiated as a formal discipline in Australia by early studies for underground structures for the Snowy Mountains Scheme in the 1950s. These techniques were quickly embraced by underground mining and there has been steady development to the present time. The paper reviews the status of current techniques for rock mechanics studies and discusses some important issues such as ground support, mine filling and caving. It concludes that a considerable degree of engineering judgement is still required for the practical application of rock mechanics to underground mine design.

Jan 1, 1992

By Noel N. Moebs

This report summarizes a U.S. Bureau of Mines study on the application of geotechnology to identify and minimize ground control hazards in talc mining operations in northwest Georgia. The major ground control hazard is pillar sloughing attributed to the steeply dipping orientation of a pronounced foliation in the talc ore body. The sloughing problem, which gradually reduces the effective support area of a pillar through attrition, can be minimized by appropriate artificial support, as determined by a rock classification system, and by a more uniform pillar design. A boundary element model confirmed the advantages of using a uniform pillar design to avoid excessive loads on portions of irregular pillars. Instrumentation to measure roof convergence and pillar loading was installed at selected locations in an active talc mine but failed to detect any significant changes, suggesting that the gneiss hanging wall constitutes a strong roof that probably can support large spans between pillars and permit high extraction ratios. This interpretation also is supported by a rock classification of the hanging wall gneiss.

Jan 1, 2010

By John Treweek

FOR many years the Homestake Mining Co. has devoted serious attention to the elimination of accidents, and ground is steadily being gained in this direction. In accident prevention work it is line-plunging with perfect teamwork and not the spectacular forward pass that brings progress toward the goal. In both surface plants and under- ground workings we regard "good housekeeping" as a first requisite for safety as well as efficiency. Under this term are included all types of safety guards and protective devices as well as cleanliness and orderliness it working places. Perhaps the most important factor in safety work is to arouse and maintain employee interest. The general morale and contentment of employees is of particular importance.

Jan 1, 1938

By D. Shink

A small scale continuous flotation cell was designed and constructed at Noranda Technology Centre to develop a mobile testing flotation circuit located next to the production circuit. This mobile small scale flotation pilot plant can easily and economically be set up at any circuit in a mill and used to evaluate and predict plant performance against a given flotation condition. The main feature of the cell, beside the provisions of automatic pulp level and feed rate control, is to provide a reduced surface to volume ratio approaching to that of an industrial machine. This paper describes the basic design and the results of various testwork carried out to date including aeration, conditioning, reagents, recirculation, flotation gas, etc. are presented in comparison with the plant production results.

Jan 1, 1992

By Robert C. Johnson

Single crystal whiskers of ZrO2 and TiO2 were grown by solution and crystallization of these oxides in molten baths. Mixtures of Na2B407 and LiC1 were the most suitable growth media for zirconia. Sodium borate alone and Na2CO3 plus SiO2 were best suited for titania. The solubilities of zirconia and titania in molten sodium borate were determined, Whether zirconia whiskers were dendritic or nondendritic depended on the temperature used. The best single crystal whiskers were grown below 1,100° C. Titania whiskers always grew as single crystals. The tensile strengths of zirconia and titania whiskers were about 15,000 psi and 50,000 psi, respectively. Modulus of rupture was about 49,000 psi for zirconia whiskers and 75,000 psi for titania whiskers. Chemical analyses showed the zirconia and titania whiskers to be pure. The zirconia and titania whiskers were shown by X-ray analysis to be, respectively, baddeleyite and rutile.

Jan 1, 1965

By C. J. Malek

The CONTOP® smelting cyclone technology is a large-scale and time-proven method which in combination with other technologies (grinding, drying, pyrolysis, etc.) provides for a cost- efficient and ecological disposal of a wide range of waste materials from industry and households. In this report the basic principle of smelting cyclone technology will be explained first. Subsequently, the paper will discuss substantial concepts for the recovery of various remainders.

Jan 1, 1996

By Walter O. Snelling

IN combating mine-fires the use of carbon dioxide as a means of producing an atmosphere in which combustion cannot be sustained, has been many times suggested and frequently tried, generally with a fair degree of success. The carbon dioxide is produced by acting on limestone with dilute sulphuric acid, large wooden boxes being used to hold the limestone, and arranged in such a manner that one box may, be cleaned and refilled with blocks of limestone while another is being used in generating the carbon dioxide. The gas is led by means of pipes of large diameter to the location of the fire, tight brattices having been previously put up as close to the fire as possible on every side, so as to limit the space to be filled with the .gas to the smallest possible volume. The cost of producing Carbon Dioxide has been, however, a decided draw-back to the use of this method, and the danger of producing carbon monoxide by the reduction of the carbon dioxide by heated carbon, and consequently bringing about an explosion, has also tended to prevent the application of this method. The use of sulphur dioxide in combating mine-fires has not, I believe, been previously suggested or tried, and yet the method presents such decided advantages over the use of carbon dioxide that it seems proper to suggest the advisability of considering it as a cheap, convenient, and safe means of fighting stubborn mine-fires. 1. Cost, Preparation, etc.-One ton of brimstone, costing from $20 to $30, will produce about 25,000 cu. ft. of sulphur dioxide gas, and allowing for all sources of loss it is probable that sulphur dioxide gas can be produced for about $1,300 per 1,000,000 cu. ft. For carbon dioxide gas, produced by the action of sulphuric acid on limestone, a good estimate would be $4,000 per 1,000,000 cu. ft., provided that sulphuric acid

Sep 1, 1908

By May J. R

Exploration, including research, has fuelled the enormous expansion of the Australian mineral industry in the last three decades. Analysis of success and failure in exploration and research has therefore potentially powerful lessons and messages which may be used to influence the future shape and direction of the mineral industry. Research has been an integral part of organised corporate mineral exploration since its beginnings in Australia in the 1930s. In corporations, the activity generally called project generation or new project development is the main expression of exploration research but mostly it goes unidentified and poorly documented except perhaps when a successful discovery is made and reported on. The competitive nature of exploration means that extended and detailed analysis of corporate exploration research across the industry is impossible to achieve.

Jan 1, 1992

By M. F. Almeida

"Due to the randomness of all factors influencing the sintering operation, a two-stepped procedure is proposed to find the best way of using stocked fines at a plant producing Fe-Mn alloys for the steelmaking industry. The approach is based on the following: (1) predict the result of the sintering operation by establishing the best multilinear regression model using some of the characteristics of the loaded material; and (2) find the best solution under a minimizing cost criteria by solving a linear optimization problem using the regression equation plus constraints on the feed and product. IntroductionSome tests carried out using 20% to 30% of sinter in the material loaded into a 60 000 KVA Tysland-Hole electric furnace producing Fe-Mn alloys for the steelmaking industry indicated: (1) a meaningful decrease in the off-gas temperature and, consequently, a better energy use due to the material higher porosity; (2) more uniform heat distribution as a consequence of the electrode reaction zone enlargement; (3) an improved furnace control resulting in a smoother operation; and (4) a decrease in gas production facilitating the off-gas treatment. For some years, this plant used only the coarse fraction of the Mn ores, thus stocking all the received and own-generated fine particles. In view of the mentioned results, a strategy for increasing the use of stocked fines was formulated, including a step where it was necessary to decide which components and respective quantities should be used in the blends to be sintered (Almeida, 1984).It is well known that several factors affect productivity and energy consumption in sinter production, also influencing the product quality. Raw materials characteristics, namely chemical and size composition, affect permeability to gases and may or may not allow a deeper bed. In general, finer ores decrease permeability, increasing electricity consumption by fans, but due to their higher specific surface area, react more completely with other components in the mixture. For coke granulometry, a compromise must be obtained in order not to burn it too quickly nor to widen the flame front, therefore decreasing productivity. Decreasing coke in the blend also acts in sinter bonding, decreasing its consistency and increasing crushing and return fines. Moisture addition also influences components mixing, pre-agglomeration, bed permeability and, consequently, sintering productivity. Therefore, optimum conditions must be established for both a given sintering plant and the components in the feed (Dawson, 1993)."

Jan 1, 1998

By Jeff Fontana, Daniel Ebin, Eric Westergren, William Currier

The PMott MacDonaldlane Train Tunnel West Extension (PTTWE) Project at HartsfieldJackson Atlanta International Airport includes the extension of the existing automated people mover system and terminal renovations at the baggage claim station. To assist with design, pricing, and assessment of risk on this progressive design-build project, 3D design models were prepared to increase visibility into realities of construction. This paper will focus on the original intent of the models and explore the additional, unforeseen value they provided throughout the design and construction process.

Dec 1, 2022

By G. P. Kundargi

India is one of the fastest growing economies in the world. The role of the Iron & Steel industry is very important for the development of the country. Iron and steel are among the most important components required for the infrastructure development of the country. This is one of the fastest growing sectors. The demand drivers for the Indian Iron & Steel industry are increase in the activities of the manufacturing industry and infrastructure development. Indian Iron & Steel industry with its strong forward and backward linkages contributes significantly to overall growth and development of the economy. The industry today directly contributes 2% of India?s Gross Domestic Product and its weightage in the official Index of Industrial Production (IIP) is 6.2%. Manganese is a main ingredient for production of steel. Almost 90% manganese is being utilized by the steel industry worldwide. Globally, there is no substitute for manganese as on date. There is huge gap between demand and production of manganese ore in the country. To meet this demand gap and to support for growth of national economy, MOIL Limited (formerly Manganese Ore India Limited), a Government Enterprises, producing annually around 1.1 million tonnes (mt) of manganese ore and value added products, has geared up with various infrastructural activities to increase the present production capacity of 1.1?1.5 mt in 2016?2017 and 2.2 mt in 2020?2021. The paper deals with the technological improvements and infrastructural development activities of MOIL; this will help MOIL to become the market leader in manganese ore production globally in the coming years.

Aug 1, 2013

By C. E. McManus

MANY mechanical advances have been made on mining equipment during the year 1951. There have been a number of trends established and many modifications made on open-pit equipment to increase the efficiency and availability of all the machines necessary in the moving of overburden and iron ore. Some years ago, the trend toward larger shovels for the loading of off-highway trucks began, but in the last year, it has become general practice to use the 5 to 7 ¼ -yd quarry-type shovels in the loading of haulage units. For years these larger shovels were used in the locomotive haulage pits. As the truck capacities increased from 15 to 20 to 30 tons, the need for larger loading units became apparent. Today in most mines, large shovels are in evidence and a few 8-yd shovels will be delivered this year for loading off-highway trucks. Torque Converter-Shovel The Diesel-driven shovel with its friction bands has been modernized with the torque converter. There have been about ten shovels remodeled to take a torque converter in the drive system. The large high-torque, low-speed Diesel engine was removed and replaced by a high-horsepower, high-speed, automotive-type engine. This engine was connected directly to the torque converter. The torque converter was connected to the shovel through the standard original sprocket and chain. Dual governors controlled engine performance. One governor controlled the high idle of the engine; the other governor, which is connected through a flexible shaft to the output shaft of the converter, controlled the loading of the engine. With this dual governor hook-up, the engine anticipates load conditions and is operating at high idle and full throttle before the shovel load is transmitted back through the converter to the flywheel. It has been found that with this automotive-type engine and converter, the shovel capacity has been increased about 20 pct. Also, the wear on the friction bands, breakage of hoist cables, and other mechanical breakages has been reduced materially. Alloy-Steel in Shovels The shovel equipment manufacturers have been experimenting with low-temperature-strength, high-alloy steels to combat the excessive breakage that occurs in extremely cold weather. High-nickel alloy steel has been used in critical areas that are affected by low temperatures, the most notable being dipper sticks. Most shovels ordered today are equipped with some of this special, alloy steel. More and more manganese alloy is being used for replacement parts such as shovel pads, idlers, drive sprockets, etc. Although the initial cost of these parts is considerably higher than the standard replacement items, the life of these manganese parts is considerably longer and well worth the added expenditure. Dipper-teeth repair is still a problem. Most companies use the small replaceable inserted tooth. It has become common practice among some of the companies to "job out" their dipper-tooth repairs to outside welding companies. This necessitates an additional inventory of teeth, but it does guarantee an adequate supply of replacement teeth at all times. These contractors have set up their shops on a production basis and can do an acceptable job at a high rate of speed. Thermite welding has been used in retipping teeth. To date, the process cannot be called successful but with improvements the time required to repoint the dipper teeth will be decreased considerably. The submerged arc process has been tried in the replacement of these dipper points, but like thermite welding has not proven successful. Here again, if a method can be developed to use submerged arc, the job of teeth repair will be made much easier. New model shovels in 6 ½ and 8 cu yd sizes fea-

Jan 1, 1952

By Albert L. Toenges

[sing tho ppsf; few Yomn t!le:.c. hcs beer. p. trqnd away frorn locomotive haulwe of cop2 frorn tile losdiw point to tho prop,nration plant of bitu~i- nnus-cod strip mlncc to a;~to~lzcd. h,71Jlr.:~. The qrostion has arisen rrhethcr this is alwqvs econ~nicd, rxcl the purpcrse or' tnf s investigation is to de- termine, if possible, the econonic limlt for ~~torieod had.we. sing tho ppsf; few Yomn t!le:.c. hcs beer. p. trqnd away frorn locomotive haulwe of cop2 frorn tile losdiw point to tho prop,nration plant of bitu~i- nnus-cod strip mlncc to a;~to~lzcd. h,71Jlr.:~. The qrostion has arisen rrhethcr this is alwqvs econ~nicd, rxcl the purpcrse or' tnf s investigation is to de- termine, if possible, the econonic limlt for ~~torieod had.we.]

Jan 1, 1938

By F. J. Hogan

In early 1982 Atlantic Cement Company, a wholly-owned subsidiary of Newmont Mining Corp. will come on line with a new water granulating grinding facility at Sparrows Point, Maryland to produce 800, 000 tons a year of separately ground granulated blast-furnace slag. The process and product will be unique to the United States. This paper will review some initial investigations undertaken to evaluate the cementitious properties of granulated slag. The effect of slag fineness on strength development is discussed and data is presented showing a relationship between glass content and hydraulicity and grindability of slag.

Jan 1, 1982

By K. E. Harrison

Acid rain legislation as proposed by President Bush [1], if enacted, will immediately refocus current thinking on the economic decision-making as related to coal preparation facilities. Unit operations currently ignored because of their costs, will become mandatory to coal plant designers and operators to ensure maximum energy recovery and sulfur reduction in the entire coal stream. In anticipation of this need, the U.S. Department of Energy, The Ohio Coal Development Office, EPRI and others are sponsoring research in several areas of coal preparation, and coal plant designers are beginning to consider more innovative techniques as they configure their flowsheets for plants of the future. Preparation plants then will have recleaning

Jan 1, 1990

By John M. Dale

Sulfur is a plentiful, low cost, unique material whose physical properties can be altered and employed in structural applications. This program was undertaken to develop an optimum sulfur based formulation for use as a coating to both seal and support mine walls. The initial effort in the program was devoted to a laboratory study of the physical and mechanical properties of a variety of sulfur base coatings that were specifically formulated for this application. Concurrent with formulation development, laboratory equipment and techniques were developed for spray applying the sulfur based coatings to the ceiling and walls of a structure that simulated the interior of a mine. Much of the formulation work was guided by the experiences encountered when attempting to spray the formulations overhead. One hundred parts of sulfur modified with 10 parts of talc, 3 parts of milled glass fiber, and 2 parts of dicyclopentadiene was found to be a fire retarded, low odor, low eye irritation, sprayable formulation for sealing and strengthening mini, walls. An invention disclosure on this formulation was submitted to the Bureau of Mines and a patent application was filed. Various mineral samples were obtained and adhesive strengths of the formulation to these samples in both the wet and dry state were measured. With the development of an attractive sulfur based coating material, attention was directed to the design, fabrication, and testing of a portable spray application unit so that coatings might be applied in the field to various rock surfaces and earth formations for further evaluation. The unit was fabricated in the Southwest Research Institute shop. Once operational, the unit's capabilities were field tested and demonstrated at three separate locations. Upon completion of the field testing, the unit was shipped to the Spokane Mining Research Center where Bureau personnel were instructed in the use of the unit.

Jan 1, 1972

By G. Nazari

ERAMET, through its subsidiary COMILOG, have rights to a rich niobium and rare earth deposit inGabon. The Mabounié deposit, is located 50 kmfromthe town of Lambaréné, in a fairly remote location. ERAMET has been developing a process to recover value metals for several years, and approached Hatch Ltd. to design a sizeable Demonstration Plant to help them further optimize the process, and prove the flowsheet is technically viable. The process employs concentration techniques to recover an upgraded Nb/REE feed material for processing in the subsequent leach step. Rare earths and niobium are selectively leached, and subsequently precipitated. Following precipitation, rare earths undergo bulk separation and are purified to produce LRE and mixed MRE/HRE products, which will be further processed by Third Parties. This paper provides a high-level overview of the process, summarizes the motivation for a Demonstration Plant in the vicinity of the deposit, and discusses technical challenges faced during the flowsheet definition and design phase. Key challenges are focused on and summaries of the methodologies used to address each challenge, as well as the solutions to overcome the challenges, are discussed. The paper provides motivation for further process simplification and concludes with a project update.

The introduction of nitro-carbo-nitrate (NCN) blasting agents has been one of the most significant innovations in the explosive industry in the last twenty years. The most commonly used blasting agent is a rather narrowly proportioned mixture by weight of 94% ammonium nitrate (AN) and 6% No. 2 diesel fuel oil (FO) that is generally designated as ANFO. Other formulations have been developed but none of these have been as extensively used as ANFO. The relative safety of the nitro-carbo-nitrate (NCN) blasting agents almost immediately suggested bulk loading techniques to obtain economies in materials handling. The first attempt at bulk handling was to pneumatically load boreholes with ANFO. When the initial experiments were made in 1957, it was apparent that there were three problem areas which needed study to minimize potential hazards. These were: 1. Static Electricity 2. Fumes 3. Safe Handling Procedures Since those early days, considerable work has been performed in evaluating these problem areas and in arriving at procedures and recommendations that would provide the required safety. Despite the relative insensitivity of ANFO type products, all normal practices for the safe handling of explosives should be obselved. Smoking should not be tolerated in the vicinity of blasting agents and misfires should be handled in the same manner as a misfire with a dynamite charge. The purpose of this Technical Report is to discuss the problems of static electricity and fumes and the solutions that have been developed. Safe handling procedures have been discussed by the Bureau of Mines and are specified by various state and local regulations. Since regulations vary from state to state, the local, applicable regulations must be followed within the area of their jurisdiction. General information is contained in a U. S. Bureau of Mines report, IC 8179, "Safety Recommendations for Sensitized Ammonium Nitrate Blasting Agents" (1963).

Jan 1, 1973