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As most subsurface drainage contractors are paid on a per-foot basis, it is important that they realize the source and extent of any delays that interrupt their effective digging time. For the purpose of this study,
delays in the operation of subsurface drainage trenching machines
Fisk, S.D., Broughton, R.S. and E.R. Norris 1972. DELAYS IN THE OPERATION OF SUBSURFACE DRAINAGE TRENCHING MACHINES. Canadian Agricultural Engineering 14(2):69-71.
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