Excavation of materials from the Earth's crust, including those of organic origin, such as coal and petroleum. Modern mining is costly and complicated. First, a mineral vein that can likely produce enough of the desired substance to justify the cost of extraction must be located. Then the size of the vein or deposit is determined, and mining engineers decide the best way to mine it. Most of the world's yearly mineral production is extracted by surface mining, which includes open-pit mining, strip mining, and quarrying. For ore bodies that lie a considerable distance below the surface, underground mining must be considered. In both techniques, excavating and extracting mineral substances involve costly combinations of drilling, blasting, hoisting, and hauling, as well as measures for health and safety and reduction of environmental impact.