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Bob
Robert Bradley
Retired Surveyor


Surveyor - Page 5


A Surveyor’s Job
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The Surveyor’s Job At A Coal Mine


Regarding Support Rules, in future every coal face, gate ripping and development heading would be different, as more and more different chocks, props, roadway supports, cutting or development machines were experimented with, each one requiring its own individual plan showing the method of support. It was not unusual to have more than a dozen different support rules. Every Support rule plan would have to have all the Manager’s Rules written out using pen and stencil as an addition to the layout ‘sketch’ (drawn to scale). Special plans were made for support when special jobs were carried out such as coalface machine changes or repair/maintenance etc. The Manager would sign the Rules after thorough checking by himself and the Surveyor. A copy of these rules would be posted at the relevant site. These plans along with the information could take several days to prepare. Furthermore a method of work for each job had to be worked out and generally that fell on the Surveyor’s shoulders as well.

Over recent years, the number of coal faces at a mine have been reduced dramatically, from up to 10 faces at some pits advancing around 8 metres a week each, down to only one face producing coal, at dramatic rates compared with the past, using the latest computer aided technology and modern mining machinery. All of the new faces are now worked by the retreat method, i.e. the development headings are driven out to the projected planned position and the face line coupled up, both at terrific rates of advance, then the face line is equipped and the face retreated, most of the surveying work being done in the development stage, only measurements required later to plot the position of the face line on a particular day.

From the planned support rules, the positions of the face chocks and other tackle would be marked out by the Surveyor with due allowance made for gradient or gate lead required etc to balance out panzer creep.

Many of these developments require thirling surveys to be carried out so that work can be carried out in two or more places at one time. The thirling or thurling is where two headings or gate roads are being driven towards one another from different or opposite directions and must couple up or hole through to one another either directly in line or to a pre set position in the correct place. Both sides of the thirling survey need to be done at least twice to eliminate the chance of any error. Some surveys can be many miles long and obviously can be high on manpower and time and of course out of necessity need to be ultra accurate. In certain roadways special times may have to be assigned for the survey work to be done, e.g. on manrider or haulage roads.

Elsecar

Following the Aberfan disaster in 1966, where a waste tip on the side of a mountain in South Wales collapsed after prolonged rain, and engulfed a school, killing 128 people, mainly children, a new Tips Act, 1969 and Tipping Rules were brought in, and plans of dirt tips were required, with contours and levels, along with sections, calculations of the amount of spoil tipped, and method of tipping, along with geological information, the position of housing within proximity of the tip, all underground workings and final tip contours in the form of overlays, needed to be updated yearly, and not exceeding 15 months between. This created many months of extra work as well as many more plans to be drawn up. The site of every dirt tip had to be investigated, right back to its ‘green field’ site position to identify the original ground contours, and the source of any stream, clay etc which could lie under the site. Plans for each year (later) or 5 yearly interval or thereabouts were made from old information and kept together with the current plans. Numerous plans had to be constructed at the very old mines still working. Special surveys and information were required by the Mines Inspectorate at the time for any colliery with a live working beneath or adjacent to a colliery waste tip, in particular slurry ponds or lagoons.

Prior to this, dirt tips were updated on an ad hoc basis, usually at the whim of the Surveyor during the summer pit holidays, when normal pit routine work was interrupted, but if other underground work took precedence, the tips were left un-surveyed!

Special tip-courses were run by the Board at selective sites for all personnel involved in tipping operations such as the workmen themselves, engineers, surface superintendents and surveyors. New standards were set for the actual deposition of the waste material. In future no McLane pyramid type tips or tips created by overhead bucket tipping. Existing waste tips were to be ‘rounded off’ and berms or tip edges or heaps were not to be created by just bulldozing material over the edge to form loosely made tips. All material had to be layered and compacted using large Euclid machines and to follow properly designed profiles. Batter boards and gradients were set out for the workmen to follow. Boreholes were drilled into old lagoon areas on the tips and electric plumb bobs or piezometers were used to record the depths of any water in the tip. These were recorded to note any rise or fall in the water table and kept with the tip plans. If problems were found, contractors were set on to excavate and right the situation.

As soon as practicable, areas of the tip were to be soiled and grassed and sapling trees planted in various areas, restoring the land, and where possible handed back to the farmer. Good crops of barley can be obtained after only one year of restoration.

In the past, both surface and underground surveys would have been plotted using a variety of protractors and parallel rulers, giving a bearing, along which a line would be drawn and a distance marked off, due allowance being made for the angle of dip (sometimes). With the introduction of grids, positions of survey stations were plotted using co-ordinates, arrived at by calculation from the survey notes. Further allowances were made with this system, as the adjustments for sea level and local scale factor needed to be applied also, to allow for the Earth’s curvature. This was using Grid North, the others being Magnetic North and True North.

Calculations were executed using logarithmic tables for numbers, sines, cosines, tangents, etc which were long and laborious. In the 1950s several types of unwieldy calculating machines were introduced e.g. ‘Brunsviga’, later followed by the ‘Curta’ and ‘Facit’, allowing the use of natural tables for the sines, cosines etc. In the 1960s electric machines came on the scene eg the modernised ‘Facit’, which speeded up the process, and in the early 1970s the hand-held battery calculator with scientific notation, e.g. ‘Texas and Casio’, but it was the late 1970s that heralded the introduction of hand-held electronic programmable calculators with rechargeable nickel cadmium batteries, ‘Hewlett Packard HP 45s and 65s’ - simple computers. Programs for different survey calculations could be written and then stored on magnetic plastic strips for future use. These were purchased for all the collieries locally by the NCB at a cost of around £400 each, and certainly speeded up the calculations. However check calculations were still necessary, as they are today, and initially these were done using previous long hand methods - just to be sure! Consternation regarding the price of these machines was voiced by members of the mining department who thought that they were not necessary!

In the 1970s and 1980s the development of the main frame computer and its associated large printer, allowing mine plans to be drawn and copied, were introduced and pioneered at a couple of local pits, Calverton and Thoresby. The earlier computers had been developed at Cannock, and used for wages calculations and then survey programmes were designed enabling the calculation of intricate closed polygonal traverses to be made, with the choice of several methods e.g., Least-squares adjustment, Bowditch or Smirnoff. These calculations could have taken days to do by long hand methods. The specially designed white, pink, green and blue coloured input sheets were sent by internal post (‘Wells Fargo’) to Cannock and received back several days later. The comparison of the results enabled the most likely value for the underground survey stations to be chosen. Copies of each were kept in special calculation folders to accommodate the A3 sized computer paper. Normal calculations at the majority of pits were on A3 or A4 sized paper and kept in envelope folders. Most of the pits left in the area after the last British Coal reorganisation was issued with PCs (Personal Computers) for use in the department. Training courses were run for all the types of calculator and computer.

Weekly or even daily face or gate advance measurements, together with face lengths and faceline surveys to detect bends and panzer creep etc as outlined before, are taken and the information given to the mining Under-officials, Undermanager, Deputy Manager and Manager, and other departments.

A sketch or plans to scale, or graphs would be drawn out following the face survey and distributed to the various departments to allow corrections to coal face cutting to be made if necessary.

Also coal face seam sections and ripping sections and cross-measures drift sections would be taken likewise. The position and size of any fault or other disturbance would be measured also and recorded and plotted on the plan of the mine.

These measurements along with lineal advance would enable the vend calculations to be done. Some of these measurements are used to plot the workings on the mine plan. Those measurements were kept in survey notebooks or foolscap / A4 sized books originally and later inputted directly from the pit note-books into the computers as they were introduced. Quite a lot of the information would be plotted on various scales and retained for future use or reference. It is important to have a good filing system for both correspondence and calculations.

Check incentive measurements taken by Deputies would be noted and kept until seen by the auditors. However this system was stopped after a while as it was finally realised that the only accurate measurements were the ones taken by the surveying staff and ultimately the Surveyor was responsible whether it was for men’s contract payments or otherwise.

Special calculations used to be done each year end from tracings made of the mine workings for the previous 12 months advance. Each working place would be traced from the working plan and ‘scaled’ and the average coal seam extraction applied to this along with the area of slope and specific gravity of the coal and dirt by calculation to arrive at a tonnage that would be compared with the actual saleable tonnage. The workings would also show the surface position of each Parish boundary that may cross such a working and by calculation after meaning the line of such a boundary by graphic means allot the amount of tonnage worked under that Parish and the neighbouring Parish. Payment would then be worked out by the rate agreed for each by ratio.

Workings from neighbouring mines that are within 115 metres (125 yards) of the boundary, need updating on the plan within 3 months. In practice, neighbouring mine Surveyors liaise on a much more frequent interval and are thus aware of any workings approaching or within the boundary of the mine. Copies of each colliery’s workings are exchanged and visits to the neighbouring pits made on a regular basis.

The Owner and Manager must provide the Surveyor of the mine with all plans, drawings and sections, and other documents and information in their possession, along with materials to prepare plans, including good office accommodation, storage and equipment to carry out surveys.

The Manager also has an obligation to the Surveyor to inform him, in writing, of a decision to finish working a district, enabling the Surveyor to carry out a final survey of the working place, before the district or seam is abandoned and sealed off. Usually this meant liaising with the Undermanager to get onto the district as soon as coal production had ceased and survey the final position of the workings and take levels, and note whether there was any make of water, any boreholes etc, before any drawing off of supports was done and the district sealed off. Many sources of potential error need to be guarded against. First of all, the instruments being used for the survey, such as a theodolite, dial, level, tacheometer, optical plummet, etc, need to be in perfect adjustment, and these need to be checked regularly and compensation adjustments carried out. The later modern instruments need to be sent to specialist instrument firms for any adjustment, due to their intricate internal design. The older instruments could have constructional defects such as eccentricity of the plate and also with use the clamps and slow-motion or tangent screws become ‘jerky’ in operation. Skill is needed also to centre the various types of reading device with the optical type instruments and particular care was necessary with the vernier types. Only with practice is it possible to note all these things and also to carry out surveys in as short a time as necessary, particularly if shaft riding times are to be kept to.

In practice readings are taken on ‘both faces’ of the instrument several times and the results meaned thereby giving the most likely value. Furthermore, all measuring tapes need checking against a known standard base, set out using an invar band, which has a very low expansion factor.  Tapes that are too long, will give a length which in practice is too short, and vice versa.   On important main traverses the correction for expansion or contraction of the steel band may be necessary if extreme temperatures are worked in.   When ground-measuring methods were used, it became very important to pack up the underside of the band or tape, in order to obtain the correct reading.  Important surveys using this system would be carried out using the bay levelling system and was painfully slow and high on manpower as level readings at each change of grade along a measurement line were necessary in order to calculate the true length of the line.   When using catenary measuring on traverses, allowances for the sag and pull of the band were necessary.  Experiments were carried out using the subtense bar method of measuring, which uses small angles and trigonometry calculations to arrive at a measured distance, but generally proved unsuitable underground due to confined space.  Nowadays, instruments using electronic distance measuring methods are used.  An infra-red beam of light is sent along a sighted line from the instrument to a special target at the other end of the line to be measured, and the beam is reflected and sent back to the instrument, which records the time taken and transposes this into a meaned distance.   Several readings are taken to ensure a good average and also several horizontal angles and vertical angles are observed from a known position, allowing a further base to be given a known value, and so on.  This instrument needs to be calibrated occasionally and is generally adjusted by a firm specialising in this type of work and are to an accuracy of + or - 5mm.  These instruments are allowed to be used underground and are sanctioned by the Mines Inspector, under a Safety Lamp approval, because a 12 volt battery is necessary in order to power it.  These instruments must not be used in places where the methane content of the general body of air reaches 1¼ %.   Methanometers are read at the site of the instrument to check for gas on a routine basis whilst observing and the reading noted down.

Levelling instruments require adjusting occasionally also, to ensure that the line of collimation is correct and that the difference in height form one point to another is correct.  In practice sighting between two points that are equidistant apart, and check levelling in the opposite direction eliminates most of these errors, and the ensuing result can be accepted as correct.  The 3-peg test would be carried out on the surface to check the amount of error and adjustment of the diaphragm and levelling bubbles would be needed to adjust the line of sight to its correct position.  Checking for ‘sluggish’ bubbles, sticking compensators on automatic levels, faulty focusing, defective ball and socket joints and slipping adjustment screws on tripods need to be guarded against and can cause errors which are not always apparent at first.

Occasional closed polygonal levellings and check levellings between a stable bench mark maybe in the pit bottom, and the bench marks in the workings inbye are carried out, and the inbye bench mark values adjusted if necessary.  Many levelling instruments used today are automatic, ie there is no final adjustment to make when lining up the instrument with the staff, as in the past, thereby speeding up the process.  These instruments, should they be thought to be in error, usually need to go to an instrument repairer for adjustment.

Occasionally some levelling would be done for checking subsidence damage on large buildings such as churches, houses factories as well as roads where damage had been done to underground services such as sewers and sewage works. For checking the underground benchmark after measuring the shaft with a modern electronic distance measurer (EDM) a check levelling with a precise levelling instrument such as a parallel plate micrometer would be carried out from a stable point nearby such as on a church where a bench mark (BM) had been created in stable ground by the Ordnance Survey.

Today, laser levels are used on building sites particularly. The instrument is set up and a revolving level beam of light is emitted and can be seen to strike the hand held staff at various positions around the site.  The main difference with the new system is that this can be a ‘one man band’ - the staff man does the reading or adjusts a positional marker on the staff and there is no one at the instrument. Other types can be used for gradients.  Underground lasers are used and set up by the Surveyor for direction and grade in cross measures drifts etc. I was the first Surveyor to install laser beams in North Notts Area for use in the dipping steep drifts from Top Hard for developing the Parkgate seam. The system was successful in keeping the headings on line and grade. These drivages both exceeded an average of 18 yards (17.5m) per week and at the time was a European record.

Some other errors can either be human, or accidental.  These types of potential error need to be guarded against, and only good surveying practice will eliminate almost all of them.   Checking the position of the instrument under or over a survey base mark by replumbing after the angling has been completed, will check to see if the instrument has accidentally been knocked slightly out of its correct position.  Likewise checking the position of the levelling bubbles on all instruments, before and after readings will also guard against the instrument having been moved by accidental knocks, either by the observer or passers by.  By checking the bubbles constantly and also by checking the centering of the instrument either over or under a station one can tell whether this has occurred or not. Careless levelling up and setting and failure to adjust for parallax of the eyepiece can cause errors.  Also the habit of gently resting one’s hands on the instrument or tripod that causes the instrument to give a false reading, as it returns to its original position when the hands are removed giving the appearance that all is well. Also, checking to see that all bolts, nuts or screws, holding the various parts of the tripod together, are tight.

The tripods used for any instrument need to be thoroughly set into the ground and clamped and skill is needed to set up an instrument over or under a survey station in low places, steep gradients or wet areas or in places where haulage ropes are running, particularly in swilleys etc.  Again speed is sometimes required and this as suggested earlier only comes with practice.

It is also very important to ensure that if a sight is being taken by an instrument or even lining in by eye, that the point being sighted to, is the correct one and has been duly marked with its own unique reference number.  Only diligence and checking will fulfill this.  Thorough training and tuition to ensure that survey assistants are diligent when using survey base marks, is a must.

A check should be made periodically to ensure that all springs are working correctly on expanding levelling staves and also that after any repair that the tape on the staff has not been stretched, or on a rigid staff that the joints or extended lengths fit correctly in their slots. Failure by the assistant to hold the staff vertically can cause major errors.  Rocking the staff gently backwards and forwards in line will give the lowest and correct reading, or the use of a staff bubble clamped to the staff will ensure its verticality provided that the bubble is physically centred by the assistant. Shining a good light onto the staff so that reading is seen easier by the observer is a skill necessary for an assistant.

Further error can be caused by not bisecting the target properly when sighting with the theodolite or dial and also failure to finely centre the instrument over or under a station after setting up and sighting to an illuminated string when close, or generally to an oil lamp flame as a target when further away.  Relighter lamps are used by subordinate staff, after training by them on the care of lamps and how to test and recognise gas. I personally attended an evening course and passed a Gas testing and hearing exam to obtain a Shotfirer’s certificate and a Deputy’s certificate. This was particularly useful during strike periods when being alone underground. Although it shouldn’t have happened it did on two occasions.

When using a levelling instrument, care must be taken by the observer to sight through the centre cross hair and not a stadia hair above or below this line when looking through the telescope eyepiece.

On the surface care must be taken to eliminate as far as possible any effect by the sun, wind and curvature of the earth.  Refraction and obstructions that ‘graze’ the sighted target causing distortion are other features to be guarded against.   When underground, the effect of a strong ventilation air velocity can cause problems with buffeting as well as whipping up dust particles into one’s eyes.

Major errors can be caused by mistakes in addition or subtraction in both setting out work using a theodolite or dial or in levelling when setting out a point or a grade line.  The arithmetic needs to be checked and preferably by another person before leaving the site.

Generally a system of signalling by cap lamp is used by the observer to the assistant when sighting, as distances between survey stations can be quite considerable or one could be in a noisy place, such as close to a ventilating fan or haulage engine, and voice instructions in these circumstances would be useless.  Hand held two-way radio transmitters have been used on the surface and proved quite successful. Underground the use of such transmitters has been outlawed in the past in coal mines, but it is possible that ‘spark proof’ transmitters may be on the horizon.  Radio transmitters are in use at the Boulby potash mine near Whitby in Yorkshire on the main roads, and for shaft signals but of course they can only be used in straight roadways without undulations.  This is Britain’s deepest shaft at about 1,200 metres.

When measuring shafts in the past either by wire or tape, allowance had to be made for the stretch or elongation and a formula for each was used in calculating the depth.  Nowadays shaft depths are measured using an electronic distance measurer laid on its side at the surface, usually supported in the stabilised cage and a sight to a reflector positioned in the pit bottom taken, from which a reading is taken to the nearest bench mark.  Similarly a levelling point is established at the eyepiece of the instrument at the surface from a stable benchmark and from the distance obtained down the shaft a value can be obtained for the pit bottom benchmark. I was the first Surveyor in North Notts to use this system to measure the shaft and the whole exercise was carried out during the 20 minutes snap time plus 10 minutes on an ordinary working day.

Checking the reading of the instrument after booking the reading is important.  It is so easy to observe say 1.080 and book down 1.008 for example, or read 120o 12’15” and book down 120o21’15”.  Good surveying practice is to read the instrument, book the reading and then read the instrument again and check what is written in the book.  This is instilled into you at the early apprenticeship stage.  Another ‘do not’, was not to sit on the instrument box.  Many surveyors broke this rule!

Inputting readings direct into a ‘storage tape’ or geodat on a modern ‘total-station’ theodolite eliminates the use of notebooks.  Field results are then downloaded into a computer and the results are calculated and if connected to a large computer printing table can be plotted out on various scales. 

Of course this system of surveying is not always suitable for general duties and maybe would only be used on a major traverse on main roadways or surface tipping complex etc.

Care is still necessary of course to make sure that the correct reading or information has been entered.

Checking that the correct number of tapes lengths have been chalk marked and recorded, and properly lined in when using steel bands or tapes to measure survey lines from one theodolite station or dial mark to another.   Measuring one direction in metres, and then in feet and inches in the opposite direction, and comparing the result by calculation can eliminate that potential error.   Check measuring to a previous known Surveyor’s mark also that can be checked up on later in the office.  However all this checking takes time, and with the best will in the world, someone interrupting one’s train of thought, someone speaking, a telephone ringing, moving machinery, men passing by etc, booking the wrong reading, can still upset the best laid plans.  Only the Surveyor’s built in ‘home-made’ checking system will ensure the best possible results, these of course would vary greatly pit to pit.  Ideas would be pooled and the best one for the conditions adopted, until a better idea came along.

All surveying instruments and tripods etc need frequent care and maintenance and should be cleaned after every underground visit.

But for the evolution of the theory of errors, it would be impossible for the various methods in use to have been devised.  This theory enables the standards of accuracy required and also the limits of error for the different types of work to be found.

The results of the majority of the surveys undertaken would be plotted on the 1:2500 scale working plan of the mine, following the calculation and check calculation of the observations of the surveys.

In an extractive industry such as coal mining, the position of the mine working, until that part is abandoned, would only be properly ‘up to date’ at the moment of the survey, and within minutes would be out of date again as further extraction of mineral continued. 

Many plans at a mine are constructed on several scales and used for a variety of purposes.


Working Plan

The Working Plan as mentioned earlier, is sectionalised and measures 2 x 1 km and contains all the workings in a particular  seam  and shows numerous other features such as all gate roads in the seam, and the outline of the workings in carmine colour; drifts or roadways out of coal or from one seam to another in burnt sienna, the boundaries of the mine in green, the shaft pillar in green;  the shafts shown as a black open circle with a horizontal line through the centre, made into a cross when abandoned;  seam sections at specific intervals in black;  faults with throw in metres, washouts, swilleys or intrusions coloured burnt sienna; levels and contours coloured violet or direction of dip of a seam shown with a black arrow with the general gradient if the area of the mine’s take is of a very shallow gradient;  borehole positions shown as a small red circle with a centre dot and annotated with a ‘u’ for underground; panel numbers and dates of surveys and other relevant information in black;  and the workings outlined and the gates drawn in red ink and internally coloured red by stipple, and any part that was known or thought to contain dangerous substances would have a green verged line at the requisite distance away from the working, and the plan would be plotted on 1:2,500 scale. 

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Abandonment Plan

Each section would have a title block along the base giving the National Grid information etc, the plan number eg, SK 43/4664, the co-ordinates of the grid lines at 500 metre intervals, the shaft co-ordinates, a graphical scale, seam name eg, Top Hard seam, seam section with immediate strata above and below, datum for levels, level at top and bottom of the shaft, any insets in the shaft with levels and a North point, showing grid north and true north.  Additional information could include shaft-sinking dates etc.


Abandonment Plan

The Abandonment Plan of a seam at a mine is deposited with the Mines Inspector and a copy kept at the mine, photographic copies on 1:2500 scale of the original Working plan being accepted as the best.  As well as showing all the workings, and all the other things on the Working plan, would also show the position of all pumps and their size and the amount of water being pumped by each at the time of abandonment, any waterlogged areas, water dams, water lodges, contours of the seam and levels around the boundary of the mine and any connections to neighbouring mines.  Having contacted the Mines Inspector regarding the abandonment he would visit the colliery and examine the plan, fill in a M I 7 form for his use, take notes given by the Surveyor regarding the number of sectional sheets or otherwise to be deposited and any other relevant information, particularly regarding safety such as waterlogged areas etc. 35mm photo slides in colour also used to be made to be kept at a different location just in case of any damage or disaster. The plan and Surveyor’s report is then sent or taken to the Mines Records Office.

The Surveyor would write and sign a report regarding the seam or mine abandonment, with starting dates for the colliery, if known, the history of the workings with relation to all available information, such as correlations and connections to other mines, shaft section, the seams worked etc. together with details of how the colliery had been oriented with the surface, etc.

The Surveyor would also sign every sectional plan to state that after thorough examination and inquiry, to his best knowledge and belief, the plan was an accurate plan of the mine. The Manager of the mine would also sign the plan stating that no further working had taken place since the date of the Surveyor’s certificate. A pre-designed block is stencilled or stamped for the purpose. The Surveyor’s and the Manager’s Certificate numbers are included as well.

If the mine is being abandoned and closed, all relevant underground plans and surface plans, including plans and sections of the dirt tips would be deposited also. All notebooks that had been used for the production of plans and sections required to be kept, would be deposited too. He would then examine every plan or document kept at his office and make the decision whether to send it to the Mining Records Office for safe keeping, send it to Head Office or to a neighbouring mine for use in the future, or destroy it. Today at the Coal Authority Mining Records office all the plans of all mining have been scanned and copied and are available to be seen on a computer screen in colour to various scales or copied via printer should a copy be required.      

With the closure of a mine, the Surveyor would also check the depth of shafts and widths and drifts etc for insets, sumps etc to enable him to calculate the amount of concrete and stone chipping fill required to fill them, and would monitor the fill by measuring the shaft depths on a daily basis by pre-measured wire incorporating an electrically operated circuit which registered when the plumb bob tipped over on reaching the top of the fill. By calculation a check on the amount actually filled against the pre-calculated amount was made and any error above say 2 or 3% for example would be investigated, and filling would be halted until the error was identified. It could be possible for a wall to collapse for example and cause slumping. A section of the shaft filling would be drawn to scale, noting all the various stopping sites, insets, type of fill and dates etc, and any measures taken to prevent the escape of gas. A booklet issued by the NCB in 1982 entitled ‘The Treatment of Disused Mine Shafts and Adits’ gives practical guidance. A further re-enactment gave The Derelict Land Act 1982 which deals with dereliction of all kinds, including coalfields.

He would also follow the demolition of the surface buildings and update the relevant plans as necessary by erasing the structures or buildings from the plan.

Mine water underground is a major point to be considered and all sources of the make of the water need to be identified. The main sources are usually aquifers that are replenished from the surface and in shallow mines may enter the mine directly via fissures, or may be from the overlying Permian or Permo-Triassic water-bearing measures where much of our local water is pumped from. Another source could be from neighbouring mines either via purpose made connections or passing through boreholes, fault planes or fissures in barriers caused by underworking in lower seams. As Surveyor at Ollerton I was also Water Officer and on occasions would take a sample of water to the Scientific department for analysis to prove whether the water was deep zone strata water or water from old workings. Usually where areas are waterlogged in a mine invariably the amount of water contained would be worked out by the Surveyor using various formulae and approximate times for pumping the water out given the size and efficiency of a pump again would rely on the Surveyor’s judgement. I had carried out several exercise in my career and it was pleasing to note that the amounts and timings were extremely close to the projected figures. A report is made out by the Surveyor outlining all the possible makes of water and its routes within the mine boundary. Further investigations are then made over a wider field by a Senior Surveyor and could even involve collieries in different Areas or different companies. Following further reports, decisions are then made by the Mining department as to the likelihood of danger to a neighbouring mine and whether continued pumping would be necessary etc. Most mine waters are highly saline and ochrous and would need treatment before being discharged. Involvement with the Water Company and National Rivers Authority would be necessary. The Surveyor would fill in relevant forms yearly with the amount of water pumped out of the mine. Some pits pumped millions of gallons a year, e.g. Creswell produced 750,000 tonnes of coal a year but pumped 125,000,000 gallons of water.