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The Mine Safety and Health Administration (MSHA) has conducted studies to evaluate dust control technologies on deep cut continuous mining sections. These surveys have been conducted in different mines using various mining methods, face ventilation systems and dust control systems. The surveys typically consist of respirable dust sampling combined with a time study of mining activities. Measurements of dust control and operational parameters are also made. Critical elements identified for controlling respirable dust in deep cut mining systems include controlling intake dust, dust collector capacity, face ventilation quantities and velocities, positioning of workers, work practices and selection of equipment. This paper discusses how the dust surveys are conducted in deep cut mining sections and how these surveys are used to identify specific dust generating sources.

Jan 1, 1999

By R. A. Jankowski

The U.S. Bureau of Mines (USBM) conducted a series of laboratory tests to investigate the effectiveness of using a flooded-bed scrubber with exhaust ventilation in deep-cut faces of up to 12.2 m in length. An experimental test program to determine the impact on respirable dust levels resulting from changes in face airflow, curtain setback distance, operator positioning, and operating parameters of the external spray system on the miner was completed. Gravimetric sampling was conducted in the immediate return and at three sampling locations on the off-curtain side of the entry. Statistically significant differences in dust levels on the order of 0.5 to 1.2 mg/m3 were observed between specific sampling locations and changes in several test parameters. Dust sampling results indicated that a flooded-bed scrubber and exhaust ventilation can be a viable dust control system for extracting deep cuts up to 12.2 m in length. The impact on methane was not evaluated.

Feb 24, 1997

By Henning E. Soderberg, Robert Brien, O&apos

Coal may be the answer to US energy problems, but it also has its drawbacks. If it is crushed, screened, dumped, or moved, the environmental engineer is faced with a dust problem. To control coal dust, at both minimum initial cost and reasonable operating cost, demands a working knowledge of dust control equipment design, as well as the coal handling operation. Here are some guidelines to reduce air volume requirements and cut overall system costs.

Jan 10, 1981

Reduce worker exposure to respirable dust without interfering with bag-filling operations. Approach A dust control hood was developed which contains and captures dust close to its source and prevents it from entering the bag-filling operator's work place. How It Works A sheet metal hood is placed around the nozzle of the bag filling machine. The hood is connected through ducts to the plant exhaust ventilation system. Air pulled into the front of the hood and around the sides of the bag picks up dust generated inside the hood, and carries it to the dust collector. The size of the hood can be adapted to fit most fluidized valve-type bag-filling machines. The height of the hood depends on the bulk density of the product and weight of the bags being filled. The 14-inch-width of the hood allows it to be used on multi-nozzle baging machines spaced 16 inches on center. Only 2/3 of the bag is actually within the hood, and this allows easy operator access for placing the bags on the nozzle.

Jan 1, 1978

By J. B. Webster

Health and Safety in the work place is of primary concern to the underground coal industry. Control of dust in the underground environment is of major importance in this concern. Utah Power and Light Mining Division has undertaken extensive studies to determine and control the various sources of respirable dust in underground high production sections. Determination of dust sources has been achieved by real-time aerosol sampling and standard gravimetric sampling on individuals and in various suspect locations. Some sources are diesel roadway dust, outby crushing, and handling equipment, face sloughing, water spray roll-back, and mining equipment. Once identified, the dust sources are suppressed or controlled and/or the workers are directed from areas of greatest potential exposure.

Jan 1, 1990

By L. Xu

Since the establishment of the standard dust concentration of 2 mg/m3, a strong effort has been made by mining engineers and researchers to provide better dust control equipment and procedures for underground coal mines. Particular areas of success have been control of dust generation by better coal-cutting strategy, better design of water sprays for dust suppression and air movement, use of scrubbers, and improved design of face ventilation systems. A drastic improvement occurred over time such that the average dust concentrations for continuous miner operators dropped from 6.5 mg/m3 in 1968 to 1.3 mg/m3 in 1980 and for auger, cutter, longwall, and roof bolter occupations from 2.7 mg/m3 in 1973 to 1.6 mg/m3 in 1980 (Niewiadomsky, 1983).

Jan 1, 1990

By Robert Pring

IN addition to the humanitarian aspects of a dust-control program, certain economic benefits are becoming more fully recognized and now furnish a greater incentive to the mill operator to eliminate the dust from his plant. It is well known that a favorable working environment promotes increased efficiency and improves the morale of em-ployees, with a consequent decrease in labor turnover rates. One progressive mining company estimates its direct and indirect labor turnover costs at from $40 to $50 per man; for skilled labor, such as machine operators, the cost may approach $100 per man. While these figures may not be typical of every plant, they do indicate a potential savings in operating costs. Dust signifies waste; its elimination de-creases maintenance costs of mechanical and electrical equipment; its recovery is often justified from the standpoint of values contained in the collected material, although in large-scale milling operations handling low-grade ore this may not be an important factor. Perhaps the most significant trend in industrial sanitation is that dust-control equipment and procedures are becoming recognized as integral parts of the mill flow-sheet. Exhaust ventilating systems are now afforded equal care in design and mainte-nance to that given other machinery more closely related to the process,

Jan 1, 1940

By Robert T. Pring

IN addition to the humanitarian aspects of a dust-control program, certain economic benefits are becoming more fully recognized and now furnish a greater incentive to the mill operator to eliminate the dust from his plant. It is well known that a favorable working environment promotes increased efficiency and improves the morale of employees, with a consequent decrease in labor turnover rates. One progressive mining company1 estimates its direct and indirect labor turnover costs at from $40 to $50 per man; for skilled labor, such as machine operators, the cost may approach $100 per man. While these figures may not be typical of every plant, they do indicate a potential savings in operating costs. Dust signifies waste; its elimination decreases maintenance costs of mechanical and electrical equipment; its recovery is often justified from the standpoint of values contained in the collected material, although in large-scale milling operations handling low-grade ore this may not be an important factor. Perhaps the most significant trend in industrial sanitation is that dust-control equipment and procedures are becoming recognized as integral parts of the mill flowsheet. Exhaust ventilating systems are now afforded equal care in design and maintenance to that given other machinery more closely related to the process. METHODS OF DUST CONTROL "Dust control" is a general term descriptive of a number of methods used singly or together to prevent particulate atmospheric contamination. These methods are, in order of their desirability, as follows: I. Change of process. 2. Isolation of process. 3. Wet methods. 4. Ventilation. a. Local exhaust ventilation. b. General ventilation. 5. Personal respiratory protection. In ore-concentration plants it is seldom practical to change a process to eliminate the dust it creates It is possible in some cases to isolate a particular dust-producing operation from the rest of the plant, provided that constant attention on the part of the operators is not required. Frequently water is used in fine crushing and fine grinding, primarily to facilitate the processing of the ore and incidentally to allay the dust produced. Wet methods, however, are not feasible in coarse and secondary crushing operations, because of the relatively great volume of water required in instantly wetting each freshly fractured rock surface. Such quantities of water would entail conveying and storage difficulties. Local exhaust ventilation is the most effective and most commonly applied control measure, wherein directional air currents through the zone of dust production draw the contaminants into a duct system. Unfortunately, only a limited amount of reliable information on exhaust ventilation is available.2-5 Of necessity these publications are rather general, being primarily concerned with engineering fundamentals. While many organizations have successfully

Jan 1, 1940

By Harry Elkin

Control of coal dust has long been an important aspect in the conventional mining of coal; the main reasons being from a health and disaster standpoint. With the advent, of mechanized longwall mining, the control of dust has required more attention due to the high extraction rate common to most longwall systems. The purpose of this paper will be to describe the dust abatement activities of the longwall operation at Sunnyside. Kaiser-Steel Corporation has three mires located at Sunnyside, Utah, with a total production averaging 6,800 tons of clean coal per day. Of this 6,800 tons, 71 % is mined with continuous miners, the remaining 29% coming from one longwall unit located in No. 3 Mine. Our first longwall panel was started in November, 1961. In October, 1966, we started mining our seventh panel. The present panel is located in the Upper Sunnyside Seam which averages five feet in thickness, but does get as low as 51 inches. The seam pitches 5.5% in this vicinity. The roof is generally good and is comprised of 10 inches of shale cap rocs overlain with sandy shale and sandstone. The floor is sandy shale and is quite undulating in nature. The present panel is 3,800 feet in length with a face of 670 feet. The major equipment employed on our longwall unit is a 125 H.F. Anderton Shearer-Loader, British Jeffrey Diamond armored conveyors and a Dowty self-advancing-roof support system. The Anderton Shearer in use on our longwall unit has a 60" diameter x 27" cutting drum. During the shearing cycle, it traverses the face at 20 feet per minute with a cutting rate of 7.5 tons/minute.

Jan 1, 1967

By Y. P. Chugh

Additional field evaluations of a modified continuous miner using a new spray system and modified scrubbers have been conducted by the authors. In this demonstration, a comprehensive package for dust control on a continuous miner which included previously developed modifications to the scrubber, scrubber intakes and the innovative chassis spray system was demonstrated. Side-by-side comparisons of the modified miner and regular miner indicated that the miner operator with the modified miner was exposed to 62% less respirable dust. Ram car operators with the modified miner had 38% less respirable dust exposure and the return air on the modified miner had 19% less respirable dust. The mining conditions during side-by-side testing were very comparable. These results support the findings of the modified spray system studies conducted earlier at different mines in Illinois on four occasions and the modified scrubber system field evaluation studies.

Jan 1, 2009

By W Frint

An area in Southwestern Wyoming is rapidly becoming the soda ash capitol of the world. Starting only 20 years ago from a unique deposit of trona, the out-put has rapidly increased until now about half of the soda ash produced in the United States comes from this area. Chemically, soda ash is sodium carbonate, a large tonnage, widely used alkali. The largest single industrial use is in glass manufacture, where 25 tons of soda ash are used in producing 100 tons of glass. Other big users are the detergent and chemical industries. The trona deposits in the Green River basin of Wyoming, were formed about 75 million years ago as part of a geologic period when an ancient lake alternately went through periods of being a large fresh water or smaller brine lake. Today these deposits lie from 800 to 3000 feet below the surface in a semi-arid, almost desert region just west of the Rocky Mountain Continental Divide at an elevation of 6200 feet. In this area there is a prevailing westerly breeze and almost every afternoon the velocity reaches very windy conditions. Rainfall is minimal, being only 6-8 inches of moisture per year with an evaporation rate exceeding 24-inches. Most of the moisture comes in winter snows or summer thunderstorms. Temperatures are low with below zero weather dur¬ing most of the winter and early morning frost is not uncommon during the summer months. There are many trona beds varying in thickness from a few inches up to 15 feet. The deposits now being mined vary from 8 to 10 feet in thickness. The ore is mined by driving tunnels either via conventional explosives or with continuous boring machines. It is transported to the shafts via conveyor belts

Jan 1, 1972

By John W. Brown

"Adequate dust control in and around rock drills is a problem that must be solvedfor the health and safety of workers running the drill as well as those working around thedrilling operation This paper will discuss the designs available from most drill manufacturers todayand the effort ‘nvolved in keeping them effective on a productive basis."

Jan 1, 1999

By L. Muñoz, L. Steffen, W. Vilas

The emission of particulate material is one of the several parameters related to environmental control in mining operations near communities. Blasting is an event that generates and leaves a large amount of dust in suspension, which can cause discomfort to communities, generating complaints that can compromise the operational continuity of the mine. The proper management of these environmental impacts is a key factor to ensure a good relationship with the neighborhoods, making a responsible mining in harmony with the environment, giving sustainability to the mining business in the medium and long term. The main goal of this work is to present different techniques and technologies applied in a large-scale open pit mine in Brazil, with operations close to a community, to minimize the emissions of particulate material into the atmosphere. For this, different technical solutions were implemented. First, a non-conventional blasting technique was introduced that incorporates special charging and timing configurations, generating a first upper layer that serves as a blanket to contain a second, higher-energy lower layer. An optimal stemming was also defined in order to minimize ejections and maximize cratering, using the scaled depth of burial theory as well as video and fragmentation analysis. In addition, changes were made in the timing between decks (to guarantee a minimum time between layers) and between holes (changing the initiation point opposite to the free face). Finally, additional measures such as humidification of the bench, use of a wind vane to identify wind direction and the construction of a physical barrier between the mine and the community were implemented as additional mitigation measures. By applying the above techniques together, in some specific zones of the mine, it was possible to considerably reduce the ejections generated by blasting versus conventional blasting without the above measures, which was demonstrated in the field with dual blasts trials. Additionally, it was possible to achieve a vibration reduction in the community of ~30%. This work demonstrates how, by applying these technical solutions, it was possible to minimize the dust and vibrations generated by blasting allowing this operation to do sustainable mining

Jan 1, 2024

By AIME AIME

THOUGH the dust-control systems in the crushing plants and other buildings at Morenci do not differ materially from similar installations in other large copper reduction works, it is probable that in few other plants has as much attention been paid to the dust problem. Possibly the most striking feature of the Morenci installation is the manner in which the necessary equipment has been built into the various structures, and the absence of unsightly pipes, ducts, and fan houses. That this result has been attained is due, in no small part, to the basic conception that the control of the dust in a milling plant should be an essential part of the process itself and not something to be tacked on later after the plant is in operation. The control systems were designed and developed along with the general plant construction program and when the first car of ore was dumped into the crusher the dust-control equipment was ready.

Jan 1, 1942

By J. P. Rider

Operating practices and resulting production from longwall faces are continually improving. Consequently, longwall operators are continually seeking to improve the dust control capabilities on longwalls. The National Institute for Occupational Safety and Health (NIOSH) has been conducting dust surveys at longwalls throughout the country in an effort to document the types of controls that are being used and to quantify the relative effectiveness of these controls. To date, surveys have been completed at longwalls in Alabama, Colorado, Pennsylvania, Utah, and West Virginia. In addition NIOSH has been reviewing longwall dust parameters provided by mine operators to MSHA to assess the status of dust control technology being used throughout the industry. Results from the underground dust surveys and information obtained from MSHA will be summarized in this paper to provide an update on longwall dust control technology and practices.

By Jerry C. Tien

China?s remarkable levels of economic growth during the past three decades have lifted almost 300 million people out of poverty. This amazing achievement has placed an increasing demand on energy and minerals, especially coal, which supplies 68.7 percent of China?s energy (June 2011). It is estimated that China mined more than 3 Gt (3.3 billion st) of coal in 2010, three times as much when compared to merely 10 years earlier. Such an impressive achievement does not come without major costs ?? including concerns with mine safety and an increasing number of occupational illnesses due to fast growth. This article reports on one of the major safety concerns in China?s coal mining, dust and dust control practices, and known cases of caol worker?s pneumoconiosis affiliated with prolonged exposure to excessive coal dusts. The exact size of China?s mining industry is not known, but it is estimated the coal industry is at least five-million people strong, and the metal and nonmetals industry probably employs another three million people. To meet increasing energy demand, China mined more than 3.1 Gt (3.4 billion st) of coal in 2010 from its 15,000 plus coal operations1, most of which are small- to medium-sized operations with annual coal productions ranging from a few thousand tons to 300 kt (330,000 st). These small coal operations are typically in remote areas, inadequately engineered, poorly ventilated and still using rudimentary drilling and blasting mining methods employing antiquated mining equipment and, presenting safety concerns, i.e., methane and dust explosions.

Jan 1, 2011

By J. W. Austin

"Introduction The Brenda dust collection system was originally designed to handle air at the 5000 ft. elevation with less than 1 grain of dust per cubic feet of air handled. The temperature variation is from 32°C in the summer to -20°C in the winter.DUST COLLECTIONOriginal Equipment 1. Primary Crusher 2 compartment baghouse, shaker type design capacity - 17,000 cfm2. Primary Screening 3 compartment baghouse, shaker type design capacity - 30,000 cfm3. Secondary Crusher 4 compartment baghouse, shaker type design capacity - 45,000 cfm4. Secondary Screening 4 compartment baghouse, shaker typedesign capacity - 60,000 cfmThe original dust collecting equipment was designed using a napped terylene fabric at an air to cloth ratio of 5:1. The ducting was designed to handle the dust laden air at 3200 ft. per minute with all elbows and blast gate sections rubber lined. The hoods and the pickup velocities were designed to handle the anticipated low dust counts."

Jan 1, 1976

By Welby G. Courtney

The Bureau of Mines conducted an exploratory field survey to determine the amount of airborne coal dust, the size distribution of the dust, and the rate of dust deposition in coal mine airways. The survey was taken at eight underground locations in operating coal mines. The rate of dust deposition in the airways depended upon the concentration of air-borne dust and decreased exponentially with distance from the dust source. The rate was seemingly independent of the size of the airborne dust particles. The rate of deposition, along a return, for the coal dust from a fade being mined with a continuous mining machine closely matched the rate for the rock dust from a trickle duster. A sample rock-dusting schedule for that return is presented; that is, the trickle duster should be operated for 3-112 hours after every five shifts to protect the average deposit of new float coal dust in the return, but operation after every three shifts is preferred, to protect an occasional heavier deposit.

Jan 1, 1982

Reduce respirable dust exposure of workmen operating auger-type continuous mining machines. Approach: An auger miner was fitted with an exhaust system which draws dust laden air through a [scruber] and discharges it behind the line curtain. How It Works: Dusty air is drawn into the space above the coal conveyor and through a scrubber, by two fans mounted side by side above the conveyor. Exhaust from the fans passes through a duct to the side of the auger miner, and into tubing that runs back and into the air return passage formed by the line curtain. See Figure 1. Of the 5,000 cubic feet per minute of air normally entering the working place, 4/5 is drawn out through the dust exhaust system. The system was installed on a Wilcox Mark 20 Miner and tested underground by personnel of the Bureau's Pittsburgh, Pa., Mining and Safety Research Center, under a cost sharing

Jan 1, 1976

By Walenty Frydel

The paper deals with highly efficient dust collecting systems of the 10-600 type which constitute new generation installations de- signed to eliminate dust hazard in headings driven with roadheaders. A vortex ventube controlling the air flow in the com- bined ventilation system by means of air vortex generated by the ventube drive unit is also presented. From the results of measurements of under-roof concentrations of methane it appears that the application of the vortex ventube makes it possible to decrease the under-roof accumulation of methane more than 10 times.

Jan 1, 1997