New technologies of coal seams extraction on the shelf under the sea ground of Ussuriysk Gulf of the sea

Thick coal seams occur in many deposits both near the surface and at depths up to 150 m and more. Coal seams with a thickness of more than 8 m can be mined layer by layer, leaving a dividing, safety coal pillar of not less than 1 m thick in the middle of the chamber height. The purpose of the pillar is to preserve the side walls of the chamber from caving in within the period of the mining. If the coal seam is divided with a rock interlayer, the safety dividing pillar may be a rock interlayer. The authors consider as examples, the seams of the Shkotovski deposit of the Artem mine, some thick seams of the Ozemi and Zaozyomi 1, 2, 3 sites, coal seams of the operating mines in the shelf of Ussuriysk Gulf. The authors offer a method to estimate the stability of the chamber walls.