Parts of the canal above Worksop were affected by subsidence from local coal mines. By 1905, traffic had dropped to 45,177 tons, of which around 15,000 tons were coal and 11,000 were bricks. Some 40 boats were still working on the canal, although a short section between Staveley and Chesterfield had become unnavigable. The canal was making a loss, with receipts of £1,837 and expenditure of £3,883 in 1905. The largest drain on resources was the Norwood Tunnel, where £21,000 had been spent since 1871, in an attempt to repair damage and raise the roof. However, on 18 October 1907 there was a further substantial collapse, and the tunnel was closed. Effectively, the canal above Worksop became redundant. Responsibility for the canal passed the London and North Eastern Railway (LNER) in 1923, who carried out regular maintenance, and repaired and enlarged the lock connecting West Stockwith basin to the River Trent between 1923 and 1925. Various attempts to reduce the growth of weed, which had first appeared on the canal in 1852, were made, with variable success, and there was a brisk trade in munitions during the Second World War. The last serious commercial traffic on the canal was the carriage of bricks from Walkeringham to West Stockwith, which ended in 1955, although there was a small trade in warp, a fine silt dredged from the Trent at the mouth of the River Idle, and used by the cutlery trade in Sheffield for polishing metal, which lasted into the early 1960s. Parts of the isolated section from the tunnel to Chesterfield were infilled and redeveloped.