Making natural paving direct from the quarry floor. After the mudstone and shale has been removed from the quarry, an excavator removes the surface layer, the laminated layers that can not be used for natural paving. The excavator is not used for removing this layer of natural flagstone blocks because it would damage them. These flagstone layers are higher in the quarry and slightly softer than the normal flagrock blocks that make the sandy yellow riven flags.
The quarry worker or delver has to use a bar to free the key stones before the blocks will move, the key stones are smaller pieces of stone between the blocks that hold them in place. The delver then has to bar the paving blocks from their natural bed or strata, when the blocks have been moved apart, the delver uses a hammer and a bolster like chisel and small wedges to rive or split the flagstone layers from the flagrock block, the slabs are easily riven and reveal a very smooth dark colour that dries to rusty orange or brown.
These natural paving flagstones are used for interior or exterior paving projects, the thickest used for exterior and the thinner layers are used for interior flooring and wall tiles. The thin layer used for flooring can also be used for restoration of roofing slates called grey slates also known as thackstones, these natural roofing slates cover traditional Yorkshire homes and other Yorkshire buildings.
The largest of the natural paving slabs have to be made smaller and are broken in half using a technique known as ‘nicking and breaking’ using the ‘delving hammer’ and ‘nicker’ (chisel) , scoring the slab by lightly hitting the chisel along a straight line on the face of the paving slab breaking it in half, this is how traditional paving and grey slate roofing slate was made.