Crib - A roof support of prop timbers or ties, laid in alternate cross-layers, log-cabin style. It may or may not be filled with debris. Also may be called a chock or cog.

Cribbing - The construction of cribs or timbers laid at right angles to each other, sometimes filled with earth, as a roof support or as a support for machinery. - http://www.coaleducation.org/glossary.htm#C

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In addition to the normal quarrying operations, a drift into the northeast wall of the middle quarry was begun about 1935 and has advanced about 2000 ft. since then. Rooms have been driven at angles to the drift along choice beds of slate. The drifts and rooms have a roof more than 35 ft. high and the main drift and rooms are all more than 40 ft. wide. There is no cribbing at any place in the mine. Several of the rooms were driven upward on a 5º slope and in some of them there was stoping. Ingersoll-Rand Jackhamers are used, and only wet drilling is practiced. - http://goo.gl/HmiEH2

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Typical passageway. Most of the cribbing is metal in the mine. - http://goo.gl/BFA1j2

i na zdjęciu - http://lh3.ggpht.com/-t-UEz33zp-c/UJH9SAXNAhI/AAAAAAAAJNY/9h...

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Broken cribbing back in the mine - http://www.waymarking.com/gallery/image.aspx?f=1&guid=23619e...

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Note added at 4 hrs (2014-12-13 19:49:59 GMT)
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Timber cribbing design for coal mine roof control (Research report / University of Alabama, School of Mines and Energy Development) - http://goo.gl/aE8Ipm

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4. A method of construction and setting a section of trench cribbing for shoring up the opposed walls of a trench, comprising providing a section of trench cribbing having opposed walls, providing a cribbing support frame structure having spaced side members to receive the corresponding walls of said cribbing and having collapsible spacing members rigidly supporting said side members in spaced relation - http://www.google.com/patents/US2987890