METHOD OF OPEN-UNDERGROUND MINING OF FLAT COAL BED OF MEDIUM THICKNESS Russian patent published in 2013 - IPC E21C41/00 

FIELD: mining.

SUBSTANCE: method includes performance of stripping works and extraction of a part of a bed reaching under drifts, with an open pit forming ledges, arrangement of extraction chambers according to the technology of deep mining of coal beds from the ledge of the pit board, preparation of reserves by arrangement of drifts, extraction of coal by facilities of underground works mechanisation. The extraction chamber is arranged diagonally relative to the bed falling line at the angle to the horizon of not more than the one permissible for a combine and a self-propelled car. The roof of the extraction chamber is fixed with a support of developing entries, for instance, with an anchor one, the distance between extraction chambers is accepted as equal to 3-4-fold width of the extraction chamber depending on strength characteristics of coal and rock massifs. Coal extraction in the chamber-to-chamber pillar is started in diagonal stopes at the side of bed rising, aligning them at the angle of 120…135 degrees to the axis of the extraction chamber, measured from the chamber head, and broken coal is transported with the self-propelled car along this extraction chamber. Then the combine is turned, and coal is removed in stopes at the side of bed falling, aligning them at the angle of 120…135 degrees to the axis of the extraction chamber, measured from the further border of the chamber; transport of coal broken in these stopes is carried out with the self-propelled car along a drift and the adjacent extraction chamber.

EFFECT: higher safety and efficiency of mining of a coal bed with medium thickness in a contour area of a pit with an open-underground method.

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