Further improvements proved necessary; attempts to ship coal directly from Saltom were unsuccessful, and an underground roadway was driven to the bottom of another pit, from whose pithead a waggonway ran to Whitehaven harbour. The pumping engine originally installed at Saltom proved inadequate, and by 1739 two much larger ones were in use. But Saltom pit allowed the working of much coal inaccessible from previous pits; by 1765, workings extended a mile and a half from the shaft and as much as three-quarters of a mile out to sea. Clerk of Penicuik (who thought it folly to have assumed the ingress of sea water would be manageable) commented: