Руская версия
Steam drilling-out

Basic information

We are actively involved in scientific and methodological assistance to integration of a new coal mining method in Russia, based on deep drilling-out of seams.

The deep seam drilling-out method is a variety of underground chamber-and-pillar development, but this one requires preparatory works for a seam in open-cut mining site. Actual open-cut mining works are means providing access to coal seams for machinery doing conventionally underground excavation. During this process, power stations, hydraulics and the entire service personnel are on the surface.

 
 
 
General view of deep seam drilling-out site
 
Open-cut mining is basically used for excavation of 2.0-2.5-meter seams at a depth of up to 200-250 meters. Excavation of less massive seams and open-cut mining at deeper levels in most cases is inefficient. Underground mining is used for excavation of seams. Underground mining is used for excavation of 4.0-4.5 meter seams at a depth of over 50 meters. Coal reserves located close to the surface, yet at a high overburden ratio, and of insignificant thickness, requiring selective extraction and etc., are most efficiently worked with the use of deep seam drilling our method.
 
Areas of efficient use of coal excavation methods
 
Deep seam drilling-out may be considered as an accessory to open-cut mining.

 

Deep seam extraction complex (DSEC)

Drilling-out works are conducted by means of a deep seam extraction complex (DSEC). DSEC aggregate is an independent coal mining system providing coal excavation when it is unprofitable to use traditional open-cut mining, or unreasoned to use underground mining.

General view of DSEC from SUPERIOR HIGHWALL MINERS, LP
 
Deep steam drilling-out allows application of ground and underground technologies, which produces maximum volumes and efficiency of excavation. There are following advantages to this method:
  • High yearly performance (up to 1.5 million tons a year by one station);
  • High coal extraction (60-75%);
  • Low dilution level, providing excavation of high quality coal;
  • High labor safety level;
  • Reasonable operational expenditures pen one ton;
  • Quick cost recovery and investments safety.

Performance and safety

High performance of deep seam drilling-out technology is provided by use of continuous miner equipped with a special device for crushing coal and its subsequent excavation to the surface.

DSEC is installed on an open site which is formed as a result of excavation of overburden coal layers rocks in the line of a block proposed when using this system. Cutting head cuts into a seam at the ground and then, cutting out coal, lifts up to the hanging side. The actions are repeated until the time the cutting-in depth equals the length of the feeder section. (6.1m). To continue seam excavation process, an operator inserts additional feeder section. Loose coal is brought to the surface with the help of two, boom section, and ribbon, conveyors. Coal is loaded by means of a loader near the complex’s stack.

To continue excavating, feeder sections are taken out of the place and out on the surface; the complex is moved into a new position where the whole process is repeated.

Safety is provided by the absence of workers in the place, non-explosive means of coal breaking, heavy-duty underground energy systems, and low rotating speed of the performing drum.

Cost efficiency of DSEC

Relatively low operational costs per ton in deep seam drilling-out are achieved due to:
  • No need to conduct preparatory underground mining excavation and overburden works (works can be conducted from any wide bench of operating casts);
  • High performance of 500 tons per man in a month, which is 4 to 5 times more than average industrial indexes.
Quick cost recovery and investments safety are ensured through the usage of minimum set of highly reliable and efficient equipment, which does not require considerable expenses on infrastructure development. There is practically no need to build capital facilities; energy resources are consumed at a very low rate, and maintenance and supply base requires minimum organizational efforts. Low personnel population allows, if necessary, rotation-based working system and helps solve social-communicational issues.

Each basic equipment package includes: DSEC, Саt-966 loaders for mounting and dismounting of sections; Саt-992 loader(with8-12m3 scoop) for loading coal excavated by DSEC; Cat-385 hydraulic excavator (back hoe) preparing site for DSEC; dumptrucks with a lifting capacity of 40 tons and more; Саt-D7, Саt-D9 and (or) Саt-D10 dozers; DZ-98 self-propelled blade glader; car-based repair shop. If it is reasonable or necessary to conduct open-cut mining works simultaneously, the equipment package can be extended through addition of Ingersoll М-45 drilling rings, excavator with a scoop of up to 20m3, dumptrucks with a lifting capacity to 200 tons.

High cost effectiveness of the deep seam excavation with DSEC can be achieved both on sites of coking and energy generating coals, particularly in surface mine take working and finishing of strip pits along boundaries. . Effective excavation can be achieved on coal seams with a thickness of 0.7-4.8meter with slope angles of 20-25°. In such cases, yearly production of one DSEC reaches 1.5 million tons, yearly production of personnel reaches 12-18 thousand tons per man. Cost recovery of such projects normally equals 2.5 years with an internal rate of return equaling 35-40%.
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