Minerals are typically found in several distinct deposit shapes: Tabular, lens, or massive. Tabular deposits are long seams or layers that are generally flat, but can also be dipping. Coal is commonly found in tabular deposits. Lens deposits are often elliptical in shape, and multiple lenses usually occur together. Lens deposits can be oriented in any direction. Massive deposits, on the other hand, are blob-like or irregular in shape. Metal sulfides (e.g., copper, nickel, zinc sulfide minerals) and rare earth minerals are commonly found as massive deposits.

The shape and size of a deposit may influence how it is mined. For instance, tabular deposits are typically mined using room-and-pillar mining or stope-and-pillar mining underground, or open cast (i.e., strip) mining above ground. Open pit (surface) or caving methods (underground), on the other hand, may be more desirable for massive deposits.

Figure: Deposits come in many different shapes, and each shape requires different mining techniques in order to best access the ore within the deposits.