spend
To break ground; to continue working.
spend: to break ore from the face by blasting or mechanical means
In mining, to spend means to extract ore or rock from the working face through drilling, blasting, or mechanical breakage. It describes the act of fracturing and loosening material so it can be loaded and removed. A miner who spends ore is actively enlarging the working cavity, advancing the excavation into fresh ground. The term is used across hard rock mining, though less common in coal work where different vocabulary prevails.
The most common method is drill-and-blast. A crew drills a pattern of holes into the face, charges them with explosives, detonates, and then spends the broken rock. The blast fractures the ore along natural joints and weakness planes, but spending is the entire operation from face to muckpile. In some operations, continuous miners or impact breakers spend rock without explosives, though the drilling-blasting cycle remains standard in larger hard rock mines.
How much rock is spent per shift depends on rock type, hole size, blast design, and crew skill. Granite and basalt require more powder and larger holes than softer ore bodies. A typical blast in an underground mine might spend anything from 50 to 500 tonnes, depending on stope geometry and depth. Poor blast design can leave oversize rock that jams into the bucket or conveyor, requiring secondary breaking and wasting time.
The word likely comes from the older sense of spend as to exhaust or consume, here meaning to use up the ore body in place. A manager might say "we're spending the west face this month" to mean that section is being actively mined. Over time, the face gets spent out, meaning it no longer yields ore economically and work moves elsewhere in the mine.
Spending sits in the sequence between development (driving permanent roads and tunnels) and stoping (the systematic extraction of ore blocks). In block caving, where large volumes collapse under their own weight, spending refers to the initial breakage that triggers the cave. In open pit, the equivalent work is called stripping or blasting the overburden, though spend is less often used there.