random

In hard rock mining, a random is the direction in which a rake-vein or similar inclined ore body dips through the rock mass. Unlike a vertical vein, which runs straight down, or a horizontal seam, a random slopes at some intermediate angle. This angle matters enormously: it determines how you will drive headings and cross-cuts, how you will extract ore without excessive dilution, and how water will flow through the working.

The random is measured as a bearing and angle of dip, typically recorded in degrees from horizontal. A vein with a steep random (say, 60 to 80 degrees) behaves almost like a vertical structure and can be followed with near-vertical shafts. A vein with a gentle random (20 to 40 degrees) requires a series of inclined workings or benches to access it economically. Some operations explicitly work along the random, driving decline ramps parallel to the ore body rather than sinking shafts perpendicular to it; this reduces hauling distance and allows gravity assistance in loading.

The term comes from old mining practice and denotes something that runs at an angle, not straight up or across. In many districts, the random of major vein systems is so consistent that it becomes a planning constraint. A change in random, or a sudden steepening or flattening of dip, often signals a structural boundary or a change in mineralization style and is logged carefully by mine geologists.

Confusion arises because random is also used more broadly in older texts to mean any natural direction or trend in the rock, but in extraction and hard rock mining specifically, it refers to the dip direction of an inclined structure. Some regions and companies use rake instead, or describe the angle explicitly; random is now less common in modern technical writing but remains standard in traditional underground mining practice and in the technical literature of established operations.