bunny
A sudden enlargement or mass of ore, as opposed to a vein or lode.
bunny: a bulbous pocket of ore in the rock
In hard rock mining, a bunny is a localized swelling or pocket of mineralized material that breaks away from the main vein structure. Unlike a consistent vein that runs through the rock body over distance, a bunny appears as an isolated mass, often rounded or bulbous in cross-section. It may contain higher or lower grade ore than the surrounding vein, and miners encounter them unpredictably when working a known ore body.
Bunnies form through hydrothermal processes where mineral-rich fluids deposit ore minerals into fractured rock. The enlargement typically occurs where pressure or temperature conditions favored precipitation, or where the host rock composition created a favorable chemical environment. They are common in quartz veins, gold deposits, and base metal mineralization. A single working vein might contain multiple bunnies separated by stretches of leaner or barren rock.
Recognition and extraction
Recognition of a bunny depends on visual inspection and sounding. Miners tap the rock face to listen for changes in tone, or expose the face systematically as they work to observe the ore distribution. Once identified, a bunny is extracted using the same methods as the vein itself, whether hand tools, pneumatic drilling, or small-scale blasting, depending on hardness and scale. Small bunnies may be picked out manually; larger ones require drilling and breaking.
The unpredictability of bunnies makes grade estimation difficult. Mining plans based on vein sampling may encounter richer or poorer actual conditions, affecting ore processing feed and recovery projections. Historical mining records often note bunny locations to guide later work in the same area, though mining reopens or deepens unpredictably.
The term bunny, informal in origin, persists in practical mining terminology across hard rock operations. Its origin is unclear, though the round bulbous shape may have suggested the comparison. It is used interchangeably with similar descriptive terms like pocket or boss, depending on regional and company convention.