open channel gateopen cityopen coastopen cutopen cut minning or minning or minningopen ditchopen drainopen end pillaringopen end wellopen flowopen flow diversion systemopen flow testopen flumeopen foldopen formopen gash fractureopen gradedopen graded aggregateopen holeopen iceopen or coast marsh or marsh or marsh or open coastopen or packed structureopen or space structureopen pack iceopen pit miningopen poreopen rockopen sheetingopen shieldopen structureopen system or open systems or open systemsopen traverseopen web beamopen web jointopen wellopencast mining or opencut mining or opencut miningopeningopening stageopenworkoperating caboperating gatesoperating headoperating pointoperating ring or regulating ring or regulating ringoperationoperationaloperational faciesoperational freeboardoperational unitoperator
