to Prevent Coal Dust Explosions in Intake Airways ... LLEM inerting tests for Pittsburgh seam coal dust and limestone rock dust using a 40 ft long ... explosion tests at the Lake Lynn Experimental Mine (LLEM) to determine the degree of rock dusting necessary to abate explosions. The tests used Pittsburgh seam coal dust blended as 38%
This report has been prepared, not only for the purpose of recording the results of the first series of coal-dust tests conducted in the experimental mine of the Bureau of Mines, but also to place before the mining public a description of the mine and an account of the objects sought in its establishment. Soon after the organization of the ...
Rock dusting is a critical practice to prevent a coal mine explosion from occurring in the first place, making an explosion much less destructive if one does occur. To reduce the danger of a dust explosion, mine operators commonly inert the coal dust by adding rock dust - usually limestone dust - which is incombustible (not prone to …
Application of fine, inert 'rock dust' (RD) to the surfaces in underground coal mines is a common method for mitigating coal dust explosion hazards. However, due to its size, RD has the potential to contribute to the respirable coal mine dust (RCMD) concentration. Though the RD component of RCMD does not appear to pose the sort of …
Lab research on the flammability of coal dust and quenching of flame by the presence of rock dust. A Bureau of Mines mine safety railroad car equipped as a movable safety and rescue station. In addition to work on safer blasting materials and prevention of underground gas and dust explosions, mine post-disaster survival and rescue was …
the meter is calibrated using a sample of the mine's rock dust, coal dust and midpoint calibration sample. The ex plosibility function of the meter only requires a sample of pure rock dust and pure coal dust for calibration. The explosibility mode (red, yellow or green color) indicates the level of explosion protection based on the ineness of
Proper rock dusting in underground coal mines can effectively eliminate the two conditions for coal dust to participate in explosion. The inert rock dust can function …
Coal dust represents an explosion hazard in underground coal mines, which has been demonstrated collectively by experimental work and documentation of coal mine explosion disasters, and. Coal dust …
stone). If an explosion should occur, the rock dust disperses, mixes with the coal dust and prevents fl ame propagation by acting as a thermal inhibitor or heat sink. To investigate this process in more detail, a number of ex plosion experiments using various coal dust and limestone rock dust mixes have been carried out at the Lake Lynn
This simple-to-use handheld device provides a pass/fail assessment of coal mine dust samples, allowing for immediate action by operators or regulators to eliminate an explosion hazard. Development of the CDEM required significant research by NIOSH Mining and its predecessor program in the U.S. Bureau of Mines, in collaboration with …
To prevent coal dust explosion propagations, rock dust needs to be lifted and suspended in the air with the coal dust during an explosion. The addition of anti-caking agents prevents caking of rock dust in the presence of water. Mining and rock dusting processes can frequently create alternating layers of rock dust and float coal …
An experimental investigation was carried out on coal dust-inertant mixture explosions. Tests of explosion severity and flammability limit were conducted by using the Siwek 20 L vessel and ...
Coal dust explosions in underground coal mines are prevented by a generous application of rock dust (usually limestone). If an explosion should occur, the rock dust disperses, …
NIOSH conducted a series of large-scale explosion experiments at the Lake Lynn Experimental Mine to investigate the inerting effect of limestone rock dust. Post-explosion dust residue samples were analyzed to infer flame travel. ... Numerous experiments were conducted using a pulverized Pittsburgh coal dust (PPC) mixed with …
This paper will examine the particle size distributions, specific surface areas (SSA), and the explosion suppression effectiveness of these rock dusts. It will also discuss related findings from other studies, including full-scale results from work performed at the Lake Lynn Experimental Mine. Further, a minimum SSA for effective rock dust will ...
In a coal dust explosion, the limestone rock dust may undergo thermal decomposition into cal cium oxide and carbon dioxide as shown by Equation 1. However, some of the …
propagate an explosion down an entry. A coal dust explosion can generate sufficient air pressure to disperse dust from entry srfaces au nd draw it ito the expanding n …
Based on large-scale and laboratory-scale explosion test results, NIOSH identified that rock dust should have a minimum surface area of ~2,600 cm 2 /g in order to inert a coal dust explosion at the 80% incombustible content limit in the absence of methane. Anti-caking rock dust has proven to be as effective or better than regular rock …
Coal dust explosions in underground coal mines are prevented by generous application of rock dust (usually limestone). If an explosion should occur, the rock dust disperses, mixes with the coal dust and prevents flame propagation by acting as a thermal inhibitor or heat sink.
propagate an explosion down an entry. A coal dust explosion can generate sufficient air pressure to disperse dust from entry srfaces au nd draw it ito the expanding n combustion zone. Heat transfer t coal duosrt paticles results i the production n of volatiles and tars from these particles. At high temperatures, the product reacts with
In order to prevent the formation of an explosible coal cloud, rock dust (usually finely ground limestone) is spayed over the coal dust in mine entries to create an inert dust mixture. To render such dust sufficiently inert, U.S regulations require that rock dust be added to the coal dust such that there is a minimum of 65% incombustible matter ...
In the coal mining industry, rock dust (usually limestone) is added to the coal dust deposits to act as a heat sink and inhibit flame propagation. If a sufficient amount of rock dust …
Coal is a low-cost and high-calorific-value fuel. The coal mining industry worldwide has been suffering from severe accidents due to coal dust explosion hazards since its inception. Statistically, it was observed that 12,489 fatalities had occurred in 104 reported mining accidents from coal dust explosions during 1900–2020. There are …
Figure 4. An explosive layer of float coal dust covers a tray filled with rock dust; both materials were subjected to moisture and then dried. A pulseof air applied across the top of the tray removed only the layer of still dispersible float coal dust but not the caked rock dust..... 5 Figure 5.
The 415 underground coal mines produced an estimated 331.7 million short tons of coal in 2009. The average price of coal in underground mines in 2009 was $55.77 per short ton and was obtained from the U.S. Department of Energy (DOE), Energy Information Administration (EIA), Annual Coal Report 2009, October 2010, Table …
Controlling float coal dust in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more effective and efficient use of rock dust. A prototype flooded-bed scrubber was evaluated for float coal dust control in the return of a continuous miner section.
• The explosion tests were initiated using a thin layer of standard Barbara coal dust on top of a layer of limestone rock dust and the explosion severities were assessed in terms of flame travel and pressure impulse. • The experimental results gathered using a strong ignition source indicated that the suppression properties of
Rock dusting has been used for about 100 years by applying the inert rock dust (typically limestone or dolomite) to increase the total incombustible content of …
Experiments conducted with limestone dusts and dolomitic marble dusts have indicated that when rock dust is wetted and subsequently dried, it becomes a …
A variety of dust control methods are often applied in coal mines, among which the application of wet scrubbers has proven to be an efficient technology for the removal of dust in airstreams, rather than diluting or confining the dust. In this paper, a wet scrubber design was developed. Based on a self-designed experimental test platform, …