Apart from a short section in the middle, the tunnel was lined with bricks, and so the company established a brickworks at Harthill, and advertised for brickmakers. Three million bricks would be required, and the company would supply the materials and the coal needed to fire them. This should have been easy to do, as the area around Norwood Hill had plentiful coal deposits, but a clause in the Act of Parliament stated that all minerals found during the construction of the canal remained the property of the person from whom the land had been bought, and so the canal company had to negotiate with the Duke of Leeds to buy supplies of coal, in some cases from their own land.
The tunnel was lined with bricks, so a brickworks was established at Harthill to produce them. The company needed three million bricks and would provide materials and coal for firing. This should have been straightforward as the area around Norwood Hill had abundant coal deposits. However, a clause in the Act of Parliament stated that all minerals found during construction belonged to the original land owner, so the canal company had to negotiate with the Duke of Leeds for coal supplies.