Pneumatic stowing seals mines

Journal Article · Tue Nov 01 00:00:00 EST 1983 · Coal Age; (United States)

OSTI ID:6705981

Brezovec, D

A mechanized technique to seal abandoned mines has been used successfully to close 13 openings at Duquesne Light Co.'s mined-out Warwick No. 2 mine, near Greensboro, Pa. The mechanized system, which uses a pneumatic stower and crushed limestone, closed the entries more economically and in less time than it would have taken to install traditional concrete block stopping and clay plug seals, according to John C. Draper. Draper, a mining engineer with Duquesne Light's coal department, was in charge of installing the Warwick seals in a Bureau of Mines-sponsored field test on the pneumatic sealing technique. The lowest estimated cost for installing conventional stopping and plug closures for the 13 Warwick openings was $225,000, says Draper, while the openings were closed using the mechanized system for $245,000. Draper says the newer stopping cost more in the instance because work was stopped often to gather information for the experiment. The experimental closures were installed in 38 days. The job would have taken at least 149 days if traditional closures were being installed, Draper say. To install a traditional concrete block/clay plug closure, the mine opening must be cleaned thoroughly and the roof must be supported for some 3 ft from the outside. Then a solid wall or stopping must be built 25 ft from the surface and the entry must be packed with clay to the surface. Much of this job requires workers to remain underground. In pneumatic stowing, 1 1/2-in. crushed limestone with fines is conveyed through a pipeline and into the mine opening under low air pressure. Watertight seals can be installed by blowing about 10 ft of rock into the opening against the top to act as roof support. Safety posts are installed and about 10 or 15 ft of mine entry is cleaned. About 2 in. of raw cement or bentonite is placed on the floor and limestone mixed with dry cement or bentonite is blown into the opening.

• OSTI ID: 6705981
• Journal Information: Coal Age; (United States), Vol. 88:11
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ABANDONED SHAFTS
PLUGGING
STOWING
PENNSYLVANIA
COAL MINES
BENTONITE
CEMENTS
CLOSURES
COMPARATIVE EVALUATIONS
COST BENEFIT ANALYSIS
LIMESTONE
MATERIALS HANDLING EQUIPMENT
MINING ENGINEERING
PIPELINES
PNEUMATIC TRANSPORT
PNEUMATICS
ROCKS
STRATA CONTROL
SUPPORTS
UNDERGROUND MINING
BUILDING MATERIALS
CARBONATE ROCKS
CLAYS
ENGINEERING
EQUIPMENT
FEDERAL REGION III
FLUID MECHANICS
MATERIALS
MECHANICAL STRUCTURES
MECHANICS
MINE SHAFTS
MINES
MINING
NORTH AMERICA
SEDIMENTARY ROCKS
SHAFT EXCAVATIONS
TRANSPORT
UNDERGROUND FACILITIES
USA
012000* - Coal
Lignite
& Peat- Mining