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Extraction of Block Limestone
Statement of need for mineral
Pooil Vaaish Quarry produces 3 classes of stone, each with a different use:
Dimensional Stone – this is a unique material that polishes down to a pure shiny black. Pooil Vaaish has been quarried since at least the 1350’s with examples of the material in Castle Rushen and Rushen Abbey. We have received a number of quotation requests to supply polished stone in tile and slab form for international projects in Dubai and Mexico. Additionally, we are approached frequently to supply stone for restoration and new build projects in the UK.
The material has been verified as having been used in a number of Christopher Wren buildings including, most famously, the West Steps and Floor of St Paul’s Cathedral and the 311 spiral stairs inside The Monument to the Great Fire of London. We have supplied a large amount of stone for restoration work to both of these buildings and are frequently asked to supply material for other restoration projects. Last week we were asked to provide stone for restoration work for some tombs at Bunhill Burial Ground in Islington dating to the 18th and early 19th Century by the City Surveyor to the City of London.
Building Stone – Pooil Vaaish Quarry is the only limestone quarry on the island producing building stone for walling and cladding projects. It is important to retain the vernacular for use within conservation areas. Over the past few years thousands of tonnes of building stone have been imported onto the island and this continues today.
Waste Stone – As a direct by-product of the dimensional and building stone, an element of waste stone is produced which is suitable for a range of applications including filling gabion baskets, rockery stone or can be crushed to produce Type 1 roadstone.
METHOD of Statement of Working
Once the overburden is stripped back, the poor quality stone will be carefully removed with the digger and stockpiled in accordance with the location plan for campaign crushing once a year on site.
The dimensional stone underneath is drilled using a compressor and extracted using hydraulic plug and feathers. It is not possible or desirable to use aggressive quarrying techniques such as blasting as this would just damage the valuable stone. Large blocks are eased out with a telehandler and stockpiled on the existing concrete hard standing prior to loading onto a flatbed trailer for export. Maximum payload of 24 tonnes, maximum length of the unit 12 metres.
Smaller pieces of stone are transported to the hydraulic guillotine for processing into building stone. No more than 50 tonnes of processed building stone will be stockpiled on site in accordance with the location plan prior to delivery to clients using an HGV with a maximum payload of 19 tonnes.
Waste stone will be stockpiled in accordance with the location plan for processing annually by a crusher brought on-site for a short period of campaign crushing lasting no more than a week.
It is not possible to forecast the proportions of mineral products until the mineral is exposed and extracted.
It is not possible to confirm a phased scheme of working the limestone. The geological properties of the limestone beds in the quarry differ both within the bed and between beds and are suitable for different end uses. Mineral is excavated from multiple beds simultaneously depending on market requirements. However, initially, work will be concentrated in the southern part of the quarry. This is to provide sufficient room for the creation of the buttress and to ensure that mineral reserves underlying the footprint of the buttress are extracted prior to its construction, avoiding the sterilisation of the mineral.
There will be ~~n~~ excavation below the level of the current quarry floor level. (ref drawing Proposed Restoration Landform).
Working hours at the quarry will be 08.00 – 16.30 daily. Monday to Friday. There will be no working on weekends or back holidays. No vehicles transporting minerals or overburden will leave the quarry until after 9am.
No more than 1 wagon will be used between the hours of 9.00 to 16.30hrs. Wagons will not exceed 20mph on the Pooil Vaaish Road.
Vehicle movements to remove dimension or building limestone off site would be limited to the use of one flatbed in any one day or one wagon of 19 tonnes. The removal of campaign crushed rock would be limited to 9 loads (18 vehicle movements) per day for 5 working days, 1 week per year.
Vehicle movements to remove overburden off site would be limited to 5 loads per day (10 vehicle movements) for 1 week in every 5 weeks, 475 tonnes per week. 4 940 (p.a.)
Following discussions with DOI Health and Safety at Work Inspectorate (HSWI) a one-way traffic system will be operated within the quarry, with separate accesses maintained for access and egress as shown on the attached plan.
With the exception of campaign screening once a year, none of the plant or equipment is very noisy. The drilling operation involves an average of 4 drill holes per block each taking about 5 minutes to achieve. If a chainsaw is used it would be mounted on a tractor with the majority of the noise absorbed by the stone itself. Lifting of the stone blocks, movement of the stone for cropping to building stone and loading of any vehicles would be carried out by a telehandler.
The guillotine operates using a power pack which is very quiet and the guillotine itself is silent except when the stone breaks – an intermittent cracking sound. Both stone extraction and cropping are carried out within the quarry itself which would reduce any noise travelling from the site.
The mobile crusher which would be used during the campaign crushing once each year is fitted with acoustic covers and operates within the noise limits for operation within a predominantly residential area.
A digger would be used to remove overburden and to load the vehicle during the agreed times when overburden can be removed off site.
None of the processes is very dusty. The only potentially dusty operation is the campaign screening for a maximum of 1 week each year. The crushing would be carried out within the quarry which is more sheltered so it would keep the dust contained.
The existing natural drainage system for the quarry will continue to be used, with improvements to the pipe outfall to Bay ny Carrickey during construction of the buttress against the Raad ny Foillan. It is intended to extend the pipe into the quarry underneath the proposed buttress and potentially increase the size of the drainage outlet pipe through the retaining wall. We will take advice as to the advisability of increasing the outlet pipe diameter as this could have a contrary effect of allowing water to enter the quarry through the pipes at high tide. It is important to keep the pipe rodded and pressure washed to ensure that it is clear from settled debris and will allow excess water to freeflow into the sea.
The site boundary will be fenced with stock proof fencing, and the gates at the entrance and egress to the site will be locked when the quarry is not operational. Information and safety signage will be erected around the boundary of the quarry in accordance with the attached indicative signage board visual.
There have always been clauses in our mining leases and licences from the IOM Government prohibiting the removal of overburden from the site. This has historically caused enormous problems both with the quarrying operations and the visual impact of the quarry which lies on the coastal footpath around the Scarlett Peninsular. Because of the large quantity of this material this is an ever-increasing constraint which impacts on the economic viability of the quarry. Each stored stockpile needs to be moved several times to access the beds of stone. This is a long-standing problem which is making it virtually impossible to maintain a balance between having to manage the stripping and storage of soils and overburden whilst ensuring a sufficient area of limestone is exposed at any given time to fulfil demands for dimension and walling stone.
We have considered a wide range of options including the possibility of storing the overburden in the adjoining field but the landowner has refused to sell or rent us this land.
The preferred option, therefore, is to remove all of the overburden, saving $3100\mathrm{m}^3$ necessary for creating a buttress alongside the Raad ny Foillan and a small amount to be retained for landscaping. This would enable quarrying to be carried out efficiently and tidily and would leave the quarry in a far
better end state for natural colonisation by plants and wildlife. The final quarry profile would have enhanced biodiversity and geological interest.
The permission granted by the Planning Department with consensus from DED to remove a particular stockpile of some 5,000 tonnes of overburden and reprocess it at JCK's yard in Balthane Industrial Estate, Ballasalla, demonstrated that this is a realistic and viable solution for the whole of the overburden problem which will not only re-enable quarrying activities but which will provide a valuable resource (in terms of the constituent parts of the overburden) for use on the island.
A survey carried out on 3rd May 2012 has estimated that the total volume of overburden is c. 32,400m³ with an estimated total tonnage of 55,080 based on a conversion factor of 1:1.7. Please note that this volume comprises in-situ soils; in-situ weathered overburden; Scarlett Volcanic Series rocks and screened overburden and overburden already in storage. Taking into account the removal of the stockpile mentioned above, the total tonnage has reduced to 50,000 tonnes.
A drawing is attached to show the positions of the existing mounds. Also attached is a drawing showing cross sections through the proposed quarry workings and the expected levels of overburden from which the calculations have been derived.
It is necessary to retain on site approximately 3,100m³ of overburden material which will be required to construct the buttress which is located along the eastern wall of the quarry adjacent to the Raad ny Foillan footpath. The purpose of this buttress is a safety feature to "mask" the existing wall and can be seen on the restoration plan. This will reduce the overall tonnage to be taken off site to under 45,000 tonnes.
The overburden would be loaded with a 360° tracked digger onto a single 4 axle wagon which would travel between the quarry and Balthane Industrial Estate where the material would be processed into its constituent parts at the JCK recycling plant. The overburden is made up of various saleable components including sand, topsoil, gravel and concreting stone. The wagon would exit the quarry and travel over the bridge over the River Dumb which was rebuilt approximately a year ago by the Water Authority. Their engineers confirmed with us the maximum vehicle weights that it would need to carry when they designed the new bridge. The vehicle would travel through Pooil Vaaish Farm (the company has full vehicular access rights in its Deeds) and would turn right onto Pooil Vaaish Road. It would turn right onto the A5 using the traffic mirror we have installed opposite the junction to aid visibility and travel on the Castletown Bypass continuing on the A5 to Ballasalla before turning right into Balthane Industrial Estate as shown on the attached map.
The overburden will be removed in the phases identified on the attached plan.
Impact to the houses along the haul route would be kept to a minimum by using a single wagon to remove the overburden and adherence to the vehicle movements allowed within the planning conditions.
Users of the coastal footpath can only benefit from the removal of the overburden and the increase in the tonnage allowance
The quarry will be restored in accordance with the Proposed Restoration Plan and Proposed Restoration Landform drawings attached. The restoration is designed to provide a habitat with a varied biodiversity to reflect the surrounding area as well as provide a feature of geological interest to complement the existing geological significance of the Scarlett Peninsular. Following cessation of quarrying, and completion of the construction of the buttress, stand off and improved drainage, it is proposed to leave as much of the rock strata exposed on the quarry floor as well as the quarry faces to the north, east and south of the quarry. The configuration of the natural bedding planes in the limestone will enable pockets of standing water to accumulate which it is hoped will be colonised by reeds.
As part of the final restoration scheme, it is intended to install an information board to raise public awareness of the natural environment, geological, cultural and historic heritage of the quarry and area.
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