The most difficult stretch of the canal to construct was the [I 006&I007 / P 013 / Gaillard Cut] where it was necessary to build an eight-mile-long manmade canyon through a mountain. After [V 007 / dynamiting] the section of the mountain (61 million pounds of dynamite - more than the US Army had ever used in all the wars it had fought until then), it was necessary to 'file' down the sides of the canyon because of ongoing landslides set off by rock instability.
The mountain was part of the Continental Divide and as a result, the blasting and cutting of the walls had a bulging effect - the floor would at times rise a good 15 to 20 feet. The whole exercise at the time must have proven frustrating and often fruitless. But under the direction of the stubborn Goethals, a scheme was worked out whereby the walls were made less steep - shaped more like a basin than a canyon - and the problem was eventually overcome.
During the seven years of construction, 6,000 men worked on the Gaillard Cut under extremely dangerous conditions. Landslides, falling rocks and bulging floors and walls were a constant hazard.
