Dust Control Technology Research Articles

Study and Application on Dust Comprehensive Prevention and Control Technology in Tunnel Excavation by Blasting

In view of the characteristics of the blasting tunneling roadway, the paper has analyzed the distribution law and the movement rule of dust in roadway. Combined with the practical problems existing in the field, a series of methods were conducted to investigate and analyze the the dust source of tunneling, the authors propose the following optimal comprehensive directional measures: At first, using the wet shotcrete technology as more as possible to improving the shotcrete. Taking use of the corresponding measures of spraying and watering, and the use of water stemming is mandatory. The amount of wind in the exit of the ventilation duct should be controlled and the quality of water should be improved, enhancing the atomization effect. The settled dust on the walls of the tunnel should be moistened with sticking agent and the individual safeguard should be done better. Adopting the above dustproof measures should effectively solve the problems of a large amount of dust and the working environment of high dust concentration in the heading face by blasting. The working environment can be improved by the effective control for the dust concentration in the heading face .The work of dust comprehensive prevention in the heading face is of significance.

AN ENCLOSED DUST REMOVAL SYSTEM WITH DUCTING

Roadway development with fully-mechanized technologies in underground coal mines greatly improves drivage rate, drive distance and productivity. However, dust produced with the technologies is quite high. At present, dust control in roadway development is mainly through water or mist spray and dust scrubber, however their effectiveness is not satisfactory [1]. For example, when mist spray is used the dust at the face of a developing roadway is measured between 1200 and 1500 mg/m3 and the dust exposed by a roadheader operator can reach as high as 500 mg/m3 [2], these dust levels are far too high above the allowable dust level of 10 mg/m3 set out in the Coal Mine Safety Regulation in China. One of main reasons resulted to these high dust levels is lack of To develop such technologies detailed understanding of on dust sources and its distribution at the face of a fully-mechanized roadway, and development of effective dust control technologies based on the understanding. This paper describes the studies on the relationship between air flow and dust distribution at the face of a fully-mechanized roadway, establishment of an integrated gas-dust particle turbulent flow model, and numerical simulations of dust at the face with the model. Based on the results of these studies, an enclosed dust removal system with ducting was developed. The system was trialed in an underground coal mine. The system and the results of the trial are also presented in this paper.

A New Technique for Preparation of Two-Phase Foam Materials for Controlling Mine Dust and its Application

In order to overcvome the shortage of current dust control technology in coal mine, especially the traditional water spray method, a two-phase foam materials preparation experimental system was established based on the simulation of water and air conditions in underground coal mine. And a new technique which can prepare high-performance foam was proposed, and the main technical parameters and application conditions to implement foam dedusting were determined through plenty of experimental. Then, the new technique had been applied in two large underground coal mine. The results show that its dedusting efficiency to total dust and respirable dust reached 90.5% and 85.4% in the fully-mechanized excavated face, as 1.97 times and 1.88 times higher than water spray respectively. However, its water consumption is only as 10% to 20% as conventional water spray. It is proved that this new technique for preparation of foam can reduce mine dust concentration remarkably and improved the working environment obviously, and has a broad application prospect and promotion value to control dust in underground coal mines and other related industry.

Active dust control and mitigation technology for lunar and Martian exploration

Mars is covered with a layer of dust that has been homogenized by global dust storms. Dust, levitated by these storms as well as by the frequent dust devils, is the dominant weather phenomenon on Mars. NASA's Mars exploration rovers have shown that atmospheric dust falling on solar panels can decrease their efficiency to the point of rendering the rover unusable. Dust covering the surface of the moon is expected to be electrostatically charged due to the solar wind, cosmic rays, and the solar radiation itself through the photoelectric effect. Electrostatically charged dust has a large tendency to adhere to surfaces. The Apollo missions to the moon showed that lunar dust adhesion can hinder manned and unmanned exploration activities. In this paper, we report on our efforts to develop an electrodynamic dust shield to prevent the accumulation of dust on surfaces and to remove dust already adhering to those surfaces. The technology uses electrostatic and dielectrophoretic forces to carry dust particles off surfaces and to generate an electrodynamic shield that prevents further accumulation of dust. The concept of the electrodynamic dust shield was introduced by NASA in the late 1960s and later reduced to practice during the 1970s for terrestrial applications. In 2003, our laboratory, in collaboration with several universities, applied this technology to space applications, specifically to remove dust from solar panels on Mars. We show how, with an appropriate design, we can prevent the electrostatic breakdown at the low Martian atmospheric pressures. We are also able to show that uncharged dust can be lifted and removed from surfaces under simulated Martian environmental conditions. We have also been able to develop a version of the electrodynamic dust shield working under hard vacuum conditions that simulate the lunar environment. We have implemented the electrodynamic dust shield on solar arrays, optical systems, spectrometers, viewports, thermal radiators, batteries, and power systems, as well as on fabrics for spacesuits. We present data on the design and optimization of the electrodynamic dust shields and provide data on the performance of the different implementations of the technology for lunar and Martian exploration activities.

Dust Control Technology Usage Patterns in the Drywall Finishing Industry

A telephone survey was conducted to quantify drywall finishing industry usage rates of dust control technology, identify barriers to technology adoption, and explore firm owner perception of risk. Industry use of the following technologies was described: wet methods, respiratory protection, pole sanders, ventilated sanders, and low-dust joint compound. A survey instrument composed of both Likert-type scaled items and open-ended items was developed and administered by telephone to the census population of the owners of member firms of trade associations: Finishing Contractors Association and Association of the Wall and Ceiling Industries. Of 857 firms, 264 interviews were completed. Along with descriptive statistics, results were analyzed to examine effects of firm size and union affiliation on responses. Responses to open-ended items were analyzed using content analysis procedures. Firm owners rated the risk of dust to productivity and customer satisfaction as low-moderate. Half rated the dust as having some impact on worker health, with higher impacts indicated by owners of small firms. Among the available control technologies, respiratory protection was used most frequently. Several barriers to implementation of the more effective control technologies were identified. Barriers associated with technology usability, productivity, and cost, as well as misperceptions of risk, should be addressed to improve dust control in the drywall finishing industry.

Airtight negative pressure dust-control technology and application of transpersite in the coal conveyer belt system

Presented a new coal dust control program that was airtight negative pressure dust-control technology at the transpersite, combining with analysis with the movement of air currents and numerical simulation of gas-solid flow at the transpersite, and proved the mechanism of precipitation and proliferation for coal dust-controlt in theory. The technology has made good economic results at the Heidaigou Clean Plant, not only dust concentration control within 10 mg/m3 to the work site, but also substantial energy savings and cost savings.

Methods to lower the dust exposure of bag machine operators and bag stackers.

This article reviews various dust control technologies developed over the years at the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) to provide various options and alternatives to lower bag machine operators' and bag stackers' dust exposures. Dust exposure records for the past 20 years show that bag machine operators and bag stackers normally have the highest respirable dust exposures of workers at mineral processing plants. A substantial amount of research has been performed over the years to minimize the dust exposure to these workers and the intent is to present all this information together in one article. Most of the research describes engineering controls that were adapted to existing facilities to reduce the dust generated during bag filling, bag conveying, and bag stacking. In some cases, a single technique succeeded in lowering respirable dust concentrations for all three processes, thus reducing the dust exposure to both the bag machine operator and the bag stacker. In other cases, a technique was developed to specifically reduce the dust exposure of one process or the other. This research also reviews various controls for secondary dust exposure, including general ventilation requirements to mill buildings, the effects of background dust sources, and personal work practices. This information is presented to help industrial hygienists, plant managers, engineers, and workers lower the dust exposure of bag machine operators and bag stackers.

Dust Control for Material Handling Operations: A Systematic Approach

Material handling operations are used widely in industry. Often they produce unacceptable levels of dust. This article proposes a systematic approach to dust control for material handling operations. It focuses on the appropriate dust control technologies for the wide range of material handling operations. Both dust collection and dust suppression systems are considered. Comparisons are made between competing technologies using available information. Relevant literature resources are compiled and synthesized to provide the reader with the most recent design and operational information. Important areas requiring further research and development work are identified.

The Cost of Respirable Coal Mine Dust: An Analysis Based on New Black Lung Claims

Abstract The objectives of this article are (1) to provide for the first time a summation of the monetary costs of new compensation claims associated with levels of unmitigated respirable coal mine dust and the resultant lung disease known as black lung and (2) to compare these compensation costs to the cost of dust control technology research by the Bureau of Mines. This article presents an analysis of these expenditures and projects these costs over the period from 1991 to 2010, based on projected future new claims which are assumed to be approved for federal and state benefit payment. Since current and future dust control research efforts cannot change past claim histories, a valid comparison of future research spending with other incurred costs must examine only the cost of future new claims. The bias of old claim costs was eliminated in this analysis by examining only claims since 1980. The results estimate that for an expected 339 new approved claims annually from 1991 to 2010, the Federal Trust Fun...

Respirable Coal Dust Control Using Surfactants

Abstract Most coal dusts are generated when coal is being cut in the face area. With the increasing popularity of highly productive mechanized longwall sections, dust in areas where miners work has become a major concern. Field applications show that existing dust control technology is more effective in controlling coarser dust particles than finer ones (<3 μm). Other means of controlling small dust particles are needed. Laboratory studies have been conducted to re-examine the use of surfactants in controlling these fine dust particles. Since the effectiveness of surfactants depends on both the type of coal and the type of surfactant used, tests show that nonionic surfactants in general proved to be the best because of their superior wetting ability of coal through a proper balance between hydrophilic head groups and lipophilic tail groups, and their insensitivity to the water environment. Results also show that this coal wettability can be enhanced through the addition of bases such as sodium hydroxide a...

Inhalation and Retention of Thorium Dusts by Mineral Sands Workers

Heavy mineral sands consisting of ilmenite, rutile, zircon and monazite, have been mined and processed in Western Australia since 1956. The industry is a significant one; in 1995 it mined 37.4 million tonnes of sand and processed 2.6 million tonnes of heavy mineral concentrate to produce 2.1 million tonnes of the individual mineral sands, at a value of $550 million. A specific occupational health concern associated with this industry is radiation exposure arising out of the presence of thorium and, to a lesser extent, uranium with all the heavy minerals. Monazite, a rare earth phosphate, is radiologically the most significant mineral, containing typically between 5 and 7% thorium and 0.1 and 0.3% uranium. Although monazite is a low volume product, comprising only about 0.5% of total mineral sand production, it tends to preferentially concentrate in airborne dust because it is softer than the titanium and zirconium bearing minerals. This is of particular concern during the processing of mineral sands because the minerals are subjected to a variety of vigorous physical treatment processes, such as screening and magnetic, electrostatic and gravity separation. Without the application of appropriate dust control technology, considerable airborne dust (and consequently radioactivity) concentrations may be experienced by workers who operate and maintain the separation plant. While the presence of radioactivity in this industry has been long appreciated, early protective and regulatory measures were focussed on control of external radiation exposure in circuits where monazite was being concentrated and bagged. Intake of radioactive dust was only recognised as a potentially significant source of exposure in the early 1980s, following national review and acceptance of ICRP Publication 30 (ICRP, 1979). This resulted in derived air concentration (DAC) values for thorium an order of magnitude lower than those previously applied to the industry (Hewson and Terry, 1995). The issue of intake of radioactive dust prior to the mid 1980s is important because there are many long-term workers in the industry and it is well recognised that each of the five dry separation plants were very dusty. In addition, early work practices, such as use of compressed air to blow down equipment, and sweeping, banging and brushing of floors and plant equipment, coupled with limited use of respiratory protective equipment, exacerbated the potential for dust inhalation by workers operating and maintaining the separation plants. Industry management

日本の炭鉱の粉じん制御技術の現況

日本の炭鉱の粉じん制御技術の現況

Coal proximate analyses correlation with airborne respirable dust

Laboratory tests have been performed on ten coal channel samples from Eastern, Midwestern and Western United States coal provinces to investigate the relationship of coal proximate analysis characteristics with the quantity of airborne respirable dust (ARD) generated. In general, strong correlations were obtained with fixed carbon, inherent moisture and volatile content. In particular, the singular composite variable (fixed carbon/volatile)/moisture provided a significant negative exponential correlation with ARD. It is shown that this relationship is exponential and not an inverse function. The initial objective of the study was to examine the relationship between coal characteristics and ARD and the subsequent implications for underground coal mining dust control technology to protect the health of coal miners. However, it appears clear that these results may be useful for other purposes such as fundamental investigations of coal strength, environmental issues of fugitive dust from coal preparation and processing, and coal cleaning by pulverization to micrometre-sized particles.

PM10Standards and Nontraditional Particulate Source Controls: A Summary of the A&amp;WMA/EPA International Specialty Conference

An international specialty conference, jointly sponsored by the Air & Waste Management Association (AW (2) emissions source characterization; (3) source apportionment of nontraditional sources; (4) fugitive dust characterization and control technologies; (5) vegetative burning characterization and control technologies; (6) sources and controls of secondary aerosol and motor vehicle precursors; and (7...

Evaluation of occupational dust control technology in cottonseed oil mills

AbstractOccupational cotton dust control technology was evaluated in 10 oil mills throughout the cotton belt of the U.S. This evaluation was restricted to mechanical portions of each mill: seed cleaning, delintering, hulling and separating, and linter baling. Based on the process machinery observed in these mills, a 500 ton/day model cottonseed oil mill was designed. The occupational dust control systems for this mill were based on current state‐of‐the‐art technology observed during this project. Further improvements based on readily available air pollution control devices have been incorporated. In order to achieve minimal respirable dust concentrations in the mill, all dust emission points have been enclosed to the maximal extent consistent with efficient plant operations. The various processing areas in the mill were designed with negative pressure dust control systems separate from the general ventilation system. The dust control system includes coarse dust removal by high‐efficiency cyclones whose effluent discharges into pulse‐jet fabric filter bag‐houses operated at an air‐to‐cloth ratio of 20:1. The emission control system for saw‐type delinter systems were divided into small units to reduce the deleterious effects of fires.

Cotton Dust Control Studies: Effects of Engineering Controls, Washing Cotton, and Additives

This paper reviews some of the cotton dust control technology studies carried out a North Carolina State University since 1973. The purpose of the investigations has been to examine means for reducing respirable dust emission during carding, as well as to evaluate the relative merits of various dust-sampling devices. Typically the results indicate that introducing lint cleaners at the gin reduces dust emission, while the use of two types of feeder/cleaners examined does not. Steaming of ginned cotton reduces the dust emission, while storage of ginned cotton (steamed or unsteamed) beyond three months increases it. Air-cleaning devices such as properly-designed electrostatic precipitators can be quite effective in diminishing the dust concentration in the card room. Similarly, washing of cotton, the use of cleaning devices such as COTTONMASTER®, or the addition of dust suppressants to cotton reduces the emission during subsequent carding. While some of the studies are complete, others are in progress.

Review of cotton dust control technology studies at North Carolina State University. Cultural, genetic, and ginning variations

Review of cotton dust control technology studies at North Carolina State University. Cultural, genetic, and ginning variations

Review of Cotton Dust Control Technology Studies at North Carolina State University: Cultural, Genetic, and Ginning Variations

Studies of cotton dust control technology were initiated at the School of Textiles at North Carolina State University in 1973 using an especially designed model cardroom.1 These investigations have focused on, among other things, the effectiveness of innovative cleaning and opening devices developed for use in cotton textile plants, as well as the use of steaming and cleaning systems at the gin so as to reduce dust emission during carding.1,2 Also examined have been the influence of cotton cultural factors, such as geographic and temporal effects, harvesting technologies, and genetic variants.

Condensational enlargement as a supplement to particle control technologies

An experimental study has been undertaken at the Colorado School of Mines to evaluate the feasibility of using condensational enlargement to enhance the collection efficiency of existing dust control technologies for sub-micron particulates. Although the study was begun to consider the problem of respirable dust control in the underground coal mine environment, this enhancement technique shows promise for a more general class of applications. In the experiments to be reported on, particulates are injected into a continuous flow thermal diffusion chamber and subjected to varying environmental conditions; saturation ratio (rel. humidity), temperature, and residence time were the parameters. The results show that condensation on a dust nucleus (≈0.1 micron) can bring it to a size of several microns in a sufficiently short period of time as to indicate engineering applicability of the concept.