It is estimated that the eating and caving of the shore below Little Rock averages 7 64 acres per mile every year (as against 1.99 acres above Little Rock).
The bottom-slice caving system of mining begins at the bottom of a hundred-foot block of ground, a floor being excavated under the whole area, leaving pillars of sufficient size to support the ground above.
This is the cheapest of the three caving systems, but is applicable only when the deposit lies between walls of very solid rock, as otherwise wall rock is liable to cave with and become mixed with ore, which adds greatly to the expense of handling.
No, easy was not something she was willing to accept, even if it meant caving to someone she craved, whose looks drove her crazy and whose touch made her feel more at home than she did in the mortal and Immortal worlds.
The caving in of mine workings results from the excavation of large areas supported upon pillars of insufficient size.
The secretary of the Province of New Netherland, writing in Dutch, in 1650, for the information of those who wished to take up land there, states more particularly that those in New Netherland, and especially in New England, who have no means to build farmhouses at first according to their wishes, dig a square pit in the ground, cellar fashion, six or seven feet deep, as long and as broad as they think proper, case the earth inside with wood all round the wall, and line the wood with the bark of trees or something else to prevent the caving in of the earth; floor this cellar with plank, and wainscot it overhead for a ceiling, raise a roof of spars clear up, and cover the spars with bark or green sods, so that they can live dry and warm in these houses with their entire families for two, three, and four years, it being understood that partitions are run through those cellars which are adapted to the size of the family.
The subdrift caving system, fig.
He knew it, which meant he was counting on her caving at some point.
While the mine workings are small the overlying rocks support themselves of and the full pressure does not come upon the mine Caving p i llars.
In the latter case the top-slice caving method will usually be employed for the working of such intervening pillars.