The Surveyor’s Job At A Coal Mine
Prior to metrication, a 1:10,560 or 6 inches to the mile scale plan was kept, later this being replaced or supplemented by a 1:10,000 scale, both corresponding to the Ordnance Survey plans. Many working plans and abandonment plans were plotted to 2 chains to one inch (1/1584) scale, prior to the new 1/2500 scale being adopted. They were sometimes plotted on other grids as well, such as Dunnose (Ollerton) or local grids such as line of pits (Stanton Ironworks Co at Silverhill, Teversal and Pleasley pits) or Hewitt's grid around Cossall area, or other local grids for example in other parts of the coalfield. Workings surveyed and plotted to magnetic North can sometimes be suspicious as it is not always stated on the plan that correction has been made for the movement of the magnetic needle on the instrument for possibly 20 years or more and that can change at the rate of 8 minutes of arc per year (West to East), remembering that 1 minute subtends 1 inch in 100 yards. The system was not compatible between companies prior to Nationalisation and was fraught with danger. Hence a distance of 40 yards (37m) was to be left between workings of previous private companies as a safety factor for any discrepancy. Even so some workings were still encroached upon as shown on some old plans. Should there be any mistrust regarding approaching old workings today for safety, in case of water or gas being present, then a system of overlapping boreholes drilled forward and flanking are to be maintained in front of the working place.
Other scales used are 1:1,250, 1:500, both mainly for surface plans. Further scales such as 1:100 and 1:50 would be used for detail work. In the past, scales such as 8 feet or 4 feet to an inch would have been used for detail. The 1:5,000 as well as the 1:2500 scales was used for many underground plans.
All the plans would have negatives made of them, so that copies could be made, and many would form the basis for the other plans required at a mine or other office or departments eg. Planning, Geology, Ventilation, Method Study etc. Originally the negatives were made on blue tracing cloth, which was Irish linen treated with a solution to make it transparent. Later this was replaced by plastic. Rolls of the material are available in lengths of 25 metres and widths of 760mm and 1020mm approximately, equivalent to the old 30 and 40 inches of the past.
The Ventilation Plan of the mine, on 1:2500 scale, supplemented possibly by a plan on a scale showing the whole of the workings eg. 1:10,000, would show all roadways open in the mine and the air coursing through them, with direction arrows, and coloured blue for fresh air and red for foul air and would start and end at a shaft or adit. All forms of restrictions such as stoppings, doors, cloths, regulators etc, and air crossings or overcasts, fans, booster fans etc would be shown. The workings would be updated quarterly unless new air courses or road connections were made, when the plan would be updated as and when that happened. It would also show all the air measuring stations in the mine, with their number corresponding to the air measuring results recorded in a book kept by the Ventilation Officer. He would be the person who informed the Surveyor of any changes. This book would also contain small sketches of the measuring site as well as the ventilation readings, and gas content, and would be examined by the Inspector when routinely visiting the mine.
With this plan would be kept a copy of the emergency system for the reversal of the main ventilation fan should that be necessary in an emergency. An isometric drawing sometimes accompanied the plan to show a complicated layout in shafts where several insets or pit bottom roadways were directly over one another and could not be easily distinguished otherwise.
The Electrical Plan
The Electrical Plan, again on 1:2500, would show, along with schematic diagrams, all of the electrical switchgear and cables throughout the mine and shafts. The routes of the electrical cables would be shown in colour - violet for 6,600 volts, red for 3,300 volts, brown for 1,100 volts, blue for 550 volts and green for 240 volts and below. Various codings for the type of electrical gear would be used, the diagrams supplementing the working plan because it was impossible to draw the transformers and switchgear in their correct position, due to the scale of the plan. Diagrams in plan and section of the cables in the shafts and insets would also be kept.
The updated information was supplied by the Electrical department quarterly or when a major change had occurred.
It was also required by law that a Geological plan of the area in which the mine was situated, be kept. A coloured version of the exposed rocks in the area was preferred, if one existed. Many mines had to suffice with a photocopy in black and white of the 1” to 1 mile Library copies kept by the Geological Survey, many originals being destroyed in Southampton by enemy bombing during World War II. The plan showed all the surface deposits and outcrops of the various strata, together with various cross sections, with details of thicknesses etc. As will be appreciated it was far more important at shallow mines to have knowledge of outcrops and alluvial deposits etc than at deep mines. Any opencast working close to these shallow mines would need to be plotted on the plan of the mine. At Ollerton I requested and received a copy of the ‘Geology around Ollerton’ memoires that outlined every formation needed.
A Shaft Section was required, if one was available, showing all the different strata sunk through, the shaft-sinking record if possible. Also a copy of any Geological memoires if available, was recommended, as these give very detailed information and sections regarding thicknesses of strata, alluvial deposits, boreholes and shaft information over a wide area and the depth to the base of the local water bearing measures etc. Mine workings generally are not allowed to encroach within 50 metres of water bearing strata above.
The next plan was the Sketch Plan of the mine, showing all means of egress out of the mine in case of emergency. This plan was not necessarily drawn to scale, but usually it was more convenient to do so. All roadways in the mine were shown, with the airways in colour, blue for fresh air and red for return or foul air. Large arrows all pointing towards the pit bottom or adits and connections were delineated on all roadways. Telephone symbols, ambulance stations and main ventilation doors were shown. This plan was posted in the covered accommodation near to where all men passed and was updated quarterly. Its purpose is to show the workforce other ways out of the mine from their district as generally they travel the same way in and out each day.
Deputy’s District Plan
The Deputy’s District Plan, showing the area of his responsibility in colour or otherwise, and also showing the meeting station for the workmen and telephone positions. Again this plan kept in the covered accommodation and updated quarterly. Several copies made, with one set posted. There could also be various plans showing ‘out of routine’ systems, such as weekend working, or for holiday periods.
Dust Zone Plan
The Dust Zone Plan, showing all open roads in the mine, but this time portioned off into alternate black and white 160 metre lengths, each with its own unique code number, corresponding to zones marked out in the pit and the book kept by the sampler. Stone dust barrier positions shown also. The plan would be updated quarterly. Several copies made. The sampler or a Mines Inspector would take a dust sample for checking at the laboratory and would refer to the code system for location.
Rescue and Firefighting Plan
A Rescue and Firefighting Plan, showing all ventilation with direction arrows and coloured blue for fresh and red for return air. All doors, cloths, regulators, stoppings, air crossings or overcasts, fans and booster fans etc, and fire extinguishers, sand buckets, hoses and water pipes, with hydrants and valves, telephones and ambulance stations and transfer points, and any connection to neighbouring mines would be shown.
This plan used to be updated quarterly, but following a major disaster at a pit in another part of the country several years ago, where certain information was found to be missing due to the updating period, it was deemed necessary for the plan to be updated within 24 hours of any major change in future. The workings on the plan were updated quarterly, generally. The plan is constructed on 1:5000 scale and is gridded into 100 metre squares, with reference letters and numbers, enabling a position to be identified quickly, similar to the co-ordinates on an Ordnance map. Our local area had folders made, whereby the plans could be folded up like an Ordnance plan also, for ease of carrying. Liaison would be with the Ventilation and Safety departments.
Around 9 copies of this plan were in circulation, sometimes copies kept underground, all requiring the 24 hour rule amendment, with three copies being kept in the Rescue Room at the mine and one copy being updated at the Mines Rescue Station, Mansfield Woodhouse, for use in training in the event of an emergency. It was the Surveyor’s duty to see that this updating was complied with.
Tip Plans and Sections
Tip Plans and Sections, showing contour lines, tipping areas, culverts, slurry lagoons, ponds, grassed areas or trees etc, to be updated yearly. Housing, and other buildings within 250 metres of the boundary of the tip to be shown, and updated when necessary. Calculations of the volume of the spoil would be done yearly also, and slurry inputs into lagoons updated on a regular basis. Use of a planimeter could speed up the calculations.
Supplementary plans showing the original field contours before the tip was built and including any streams or swamp areas etc. Bi-ennial tip meetings were held under British Coal when tipping amounts and life expectancy were reviewed. The Surveyor would supply the plans and calculations and estimated tip and slurry lagoon life based on the updated figures.
Also Overlay Plans showing the proposed tipping height and final contour positions, together with landscaping agreed by the County Council, and underground workings in all seams and geological information and sections would be kept. Several copies distributed.
Annual Aerial photograghy of the tips based on survey networks supplemented the survey plans and the new plans were updated accordingly using these as a base.
Accident and Incident Plans
Accident Plans and Incident Plans were made as and when such an event happened, day or night. The Surveyor was on 24- hour call for such events. Usually the site of the accident or incident is measured up in sufficient detail by the Surveyor and / or his assistant in order to construct a plan and sections to forward to the Inspector for the District, for him to write his report. No work would progress at the scene of the accident other than for safety, until the Surveyor had completed his measurements.
It was generally expected that a draft copy of the plan of the site was available as soon as possible following such an occurrence, for the Manager and Inspector to peruse. Many other copies were produced for other departments involved, particularly Area Safety and unions, to enable them to complete any investigation necessary. Fatal and serious non-fatal accidents, together with serious incidents, such as fires, and dangerous occurrences such as cranes toppling over, would all require a plan being constructed. Sometimes more than 20 copies required. Generally three days would be needed to complete the task, depending upon the complexity.
- Day 1, measure up and then begin to plot the results
- Day 2 finish and trace the plan in ink, and check up with any witnesses, etc
- Day 3, finish off, and sign same, print, colour if necessary, and distribute the plans.
Following an explosion underground, generally much more information would be required as well as several plans as the area involved could be quite extensive. In such a case outside help would be requested.
Fatal Accident Coroner’s Court
At a Fatal Accident Coroner’s Court inquest, the Surveyor would attend with the Manager in case any question would arise regarding measurements or things portrayed on the plan of the incident and sometimes would have to supply further copies of the plan to the 6- man jury. Invariably following the outcome of serious accidents more work would be required by the Surveyor and his staff to assist the Manager in the carrying out of changes required by or requested by the Mines Inspectorate or higher management following detailed enquiries.
Support Rules were drawn up in great detail for every working place, including coalfaces, development headings, bye work, sinkings or salvage work. Many other plans showing the method of work supplemented the rules and all were posted at the relevant sites. The rules and plans would be signed by the Manager. Several copies of each were produced.
Firedamp Drainage Plans
Firedamp Drainage Plans (or Methane) was kept as a supplement in the form of an overlay tracing, with the sectional working plan as this plan was part of the Working Plan. Every borehole drilled for methane was plotted and shown together with its relevant information, such as direction up or down, the angle, length, its number reference etc. The borehole positions were measured up as and when they were drilled, and plotted on the plan. Sections of the strata supplemented these plans.
All the above plans are statutory and are required by law.
Many, many other plans are necessary to the running of a mine, and include:
The Manager’s plan - could be a copy of the working plan, or a combination of several, depending upon conditions, and preference. A wall plan showing the layout of the mine was probably used by most. This would be updated periodically to suit preferences, i.e. either weekly, monthly etc.
Emergency Organisation Plan
An Emergency Organisation Plan, to be used in the event of a serious situation, such as an underground fire or explosion or inrush. Several offices at the mine would be turned into different uses. The Manager’s office would generally be the Incident Room, with the Manager or higher official being the Incident controller. Another office would be designated as Underground Control, a garage for example would be set aside for use as a mortuary, if necessary. The police and press would be given facilities and a place would set aside for things like emergency winders and mobile laboratory to analyse air samples. The survey office would remain so as there would be numerous plans or answers to questions required should a major incident occur and probably x number of copies of plans or documents required to be printed etc.
Designated notices were prepared in readiness, should ever a serious event happen. The Surveyor would arrange for the new notices to be hung on the doors. He would also report to the Manager’s Office and arrange to go underground as soon as possible if required and also arrange for staff to be available to supply information or extra plans and also arrange for extra staff or equipment to be made available from a neighbouring mine, should the necessity arise. Under British Coal or NCB the Area Surveyor would be informed and arrange these matters via Senior Surveyors as necessary.
Risk Assessment Plans
Risk Assessment Plans were kept, covering all aspects of future proposed workings, such as the positions of all old shafts, underground and surface boreholes, waterlogged areas, surface deposits of moss, sand, silt etc, likely to flow when wet, and rivers etc. Liaison with the Geologist, who would supply sections. A report by the Surveyor would outline any possible hazards etc. Examined on a yearly basis and projected at least 5 years. Two copies made, one to be kept at the colliery and one at head office. The British Geological Survey at Keyworth would be contacted on a regular basis and some Surveyors would attend there with a Senior Surveyor and Geologist to check through all the relevant information regarding their particular colliery. All information would be checked through with one of the Geological Survey personnel and duly noted.
Special rules would apply to pits with workings under the sea. They would have to know the amount of strata between the workings and the sea-bed. Sea-bed contours from charts or based on sea-based boreholes would be plotted on the plan.
Spontaneous Combustion Plan
A Spontaneous Combustion Plan would be kept at high-risk collieries. This plan would show all such previous sites of underground fires or heatings, and outbursts of gas if any with dates, and also all stopping sites etc and sites for fresh air bases. Updated as required, with the workings updated quarterly.
A Pumping Plan would show the position of all pumps underground and their horse power and working capacities, the difference in height or head, the pipe lines and sizes to the pit bottom and up the shaft, the capacity of any water lodge, the position of any waterlogged areas, etc. Several copies made. Information supplied by the Mechanical Engineer quarterly. Pump positions, tanks and lodges etc measured up by the survey personnel on installation.
Airborne Dust Plan
An Airborne Dust Plan showing any roadway which had been treated with crystals etc. to dampen the dust and would also show the direction of air flow. Areas measured up and several copies distributed.
A Conveyor Plan showing all the conveyors underground with their relevant horsepower, length, width, capacity, head or gradient, speed etc and whether it is used for manriding etc. Several copies made, and distributed. Information supplied by the Mechanical Engineer quarterly. Positions of jibs, motors and return ends measured by survey personnel on installation.
A Haulage Plan showing each haulage engine with its relevant horsepower, the length of rope, the return rope pulley position, the gradient etc. Updated quarterly. Information supplied by mechanical department. Positions of engines and return pulleys etc measured by survey personnel on installation and periodically. Several copies made.
Sometimes haulage rules would have to be stencilled out and printed.
A Manriding Plan showing the layout of the various manriding facilities underground, and the type, such as rope hauled, diesel or conveyor. Details of horsepower, speed, length and possible timings. The basic information would be supplied by the Mechanical Engineer via Planned Maintenance department. Timetables for riding times would be made periodically. Calculations would be made by the Surveyor.
Fire Certificate Plan
A Fire Certificate Plan was required to be kept at the mine, with a copy at the Health & Safety Office. This plan shows every building required, with its relevant construction, and denoting the number of personnel working therein, and escape route, together with any fire extinguisher and type, hose etc, and submitted to the Health and Safety. A Fire Certificate was issued to the colliery when the local Inspector of Mines was satisfied that everything complied.