hard bottom

hard bottom

[′härd ‚bäd·əm]
(mining engineering)
A condition encountered in some opencut mines wherein the rock occasionally does not break down to grade because of an extra-hard streak of ground or because insufficient powder is used.
References in classic literature ?
With this end in view, every Sunday during my first year of office I drew the whole population of the township, willing or unwilling, up on to the mountain, where I myself had traced out on a hard bottom the road between our village and the highway to Grenoble.
Let us settle ourselves, and work and wedge our feet downward through the mud and slush of opinion, and prejudice, and tradition, and delusion, and appearance, that alluvion which covers the globe, through Paris and London, through New York and Boston and Concord, through Church and State, through poetry and philosophy and religion, till we come to a hard bottom and rocks in place, which we can call reality, and say, This is, and no mistake; and then begin, having a point d'appui, below freshet and frost and fire, a place where you might found a wall or a state, or set a lamp-post safely, or perhaps a gauge, not a Nilometer, but a Realometer, that future ages might know how deep a freshet of shams and appearances had gathered from time to time.
Due to water temperatures and terrain, sea bass numbers are better in the northern half of the state, where they inhabit broad expanses of natural live bottom with low-profile ledges and coral or limestone outcroppings, gently rolling slopes of low-relief hard bottom, and artificial structures of modules, rubble or pilings, especially in 50- to 100-foot depth.
Office of Coastal Zone Management (CZM), Northeastern University (NEU), the Nature Conservancy (TNC), and the City of Boston to plan a shoreline protection project designed to attenuate wave energy and protect transplanted eelgrass through the creation of complex hard bottom habitats suitable for important fish and invertebrate species.
Implementation and operation of the Lower Breton Sound diversion structure as proposed would render about 6,173 ha of hard bottom immediately east of the Mississippi River unsuitable for the sustained cultivation of oysters.
Four strings set over hard bottom were lost in the first four months of fishing; each lost string was set over medium or high relief.
But it was a fairly hard bottom up there even though the water was down a bit.
Yesterday and today I looked for clean hard bottom.
Hogfish (64-774 mm fork length and 0-19 years old) were observed year-round and were most common over complex, natural hard bottom habitat.
It has operated continuously until the present, but the product changed to woven, hard bottom, wooden, bushel baskets for packing vegetables.
The classification scheme included seagrasses, macroalgae (or "seaweeds"), hard bottom (coral reefs), mangroves, bare substrate, and dredged areas.
If hard bottom was emergent, the category of reef height ([less than or equal to] 1 m, > 1-2 m, and > 2 m) was estimated.