When the develoment of the Riccall Mine surface started the site was basically part of a disused WW2 airfield last used in 1958. The site was 64 acres of the RAF Riccall satellite station, the rest of the base is now part of Skipwith Common National Nature Reserve.
The first thing to do was clear the site and prepare the shafts for sinking. The shafts in the Selby Complex used a brine solution system to freeze the water bearing strata to enable sinking to take place through the water, rock and ice.
The shaft sinking contractors used at Selby were Cementation Mining Ltd who sank Wistow, Riccall and North Selby mines. Thyssen Mining (UK) sank Stillingfleet and Whitemoor mines. The water bearing strata in the Riccall shafts were frozen to a depth of 253m. To achieve the frozen zone, boreholes were drilled at uniform distances around the circumference of each shaft to 255 metres. Pipes were entered into the boreholes and filled with a saline solution. The pipes were connected to a compressor and the freezing process was started. When the freezing process was completed a thirty foot plug of ice was created around the shaft. Once the frozen zone is achieved around the shaft circumference sinking can start.
As the groundworks for the shaft tops were prepared lots of equipment was moved onto site to support the sinking operations.
A concrete preparation plant was installed onsite due to the immense quantities needed for not only the shafts but building bases, surface buildings, ductings and fan house ventilation airways.
The shaft sinking in the first thirty metres of the two shafts had major differences in design. Number one shaft was a downcast shaft, with a ventilation intake drift on the East side of the shaft. This was incorporated into the shaft design and was part of the concrete shaft wall just below the surface. The ventilation drift had a shaft heater system but was never used.
Number two shaft was an upcast shaft. The shaft design at the surface incorporated a fan drift connected to the two main 2100kw ventilation fans to the east of the shaft via 2 smooth concrete tunnels.
The shafts were sunk using drill and blast and progressed well through the water bearing strata. Once the initial surface sections were completed the sinking winders and associated equipment needed to sink the shafts were installed.
Each shaft had a 5 deck sinking stage suspended in the shaft to carry out the various processes involved. This sinking stage had 4 synchronised winches to lift and lower the stage. The processes involved in the sinking were the drilling of the shaft bottom, blasting and mucking out. The shaft walls had to be drilled, bolted and meshed. Two metre long shutters were put in place around the shaft and concrete was poured into the void between the shutters and the shaft wall to line the shaft. The shaft concrete lining was 1metre thick. Water resistant seals were fitted in the shaft lining in certain areas of the shaft sinking. In the middle of the sinking stage was an access hole for the cactus grab and kibble used for removing the shaft muck to the surface. When the sinking stage was lifted and lowered, a communication and power cable was also lifted and lowered. As the shaft was sunk concrete pouring pipes, compressed air and water pipes were installed.
Shaft sinking winder.
Any period when men were working in the shaft, doors were placed on the access to the shaft to ensure no equipment or debris fell into the shaft.
This photo shows the Cactus Grab, for mucking out, man riding kibble, meshing and strap basket. Air, water and concrete pipes are shown ready for installation in the shaft. The shaft doors are shown in the up position.
During the sinking process the mining engineers had to overcome some problems. The solutions were planned and designed into the sinking process. One of these problems was the Basal Permian Sands which had a water pressure relief system installed. This involved leaving a two metre gap in the shaft concrete lining to ensure the relief system worked and seals were installed but allowing the shaft sinking to progress. When the process was proven to work the shaft lining was completed.
Photo shows Neil Rowley on the top sinking stage at 629m depth in the shaft inspecting the basal permian sand water relief system prior to shaft lining. The shutterings and seals are visible. The shaft lining is one metre thick, sulphate resisting concrete. The concrete linings at Riccall and North Selby Mines were increased in strength due to strata hydrostatic pressures.
Photo shows temporary headgears with No1 permanent winding house built and air inlet shaft. The concrete batching plant is shown between the temporary headgears.
Photo shows fan drift to fan house under construction. The building housed two 2200kw axial flow, variable pitch fans.
Fan drift showing ventilation fans.
As the shaft sinking progressed the surface buildings and infrastructure were built simultaneously. The permanent shaft headgear was built at the side of the temporary equipment and were moved into position when sinking finished.
Photo shows permanent headgear to the right, sinking headgear on the left.
When completed in September 1983 the shaft depths were 792m at No1 shaft and 805m at No2 shaft set at 100m centres and 7.315m diameter.
Riccall Mine No1 shaft Mine car handling plant.
Riccall Mine No1 pit bottom mine car handling plant.
Car park looking at pit yard during construction.
The photograph below shows Riccall Mine when all temporary equipment was removed and all the surface buildings were fully operational. When completed the mine was barely visible from the road having used the extracted material from the shaft sinking and soil to create a natural banking around the site. The winding headgears were also designed to be shorter in height than conventional towers.
Many thanks and kind regards to Neil Rowley, an Undermanager at Riccall Mine during the development of the mine and Deputy Manager at Gascoigne Wood mine for providing photographs and information in this post.
Selby Superpit 