The companies building the canals to transport coal needed surveyors to help them find the coal deposits worth mining as well as to determine the best courses for the canals.
修建运河运输煤炭的公司需要测量员帮助他们找到值得开采的煤矿,并确定运河的最佳路线。
It's difficult to ascertain the coal deposits.
煤储量很难探明。
Canada used to be rich in coal deposits.
加拿大曾经盛产煤矿。