Princess Royal was first galed on 15th June 1842 to four brothers by the name of Priest, all of whom were Free Miners.  They in turn assigned it in November to a Mr. Morpeth.  By October 1855 the deeds had been transferred to Thomas Dyke.  It was stated that he had begun to drive a level into the upper coal measures of the Princess Royal gale seeking the Yorkley seam and he applied to the Crown for permission to build a tramroad from the level to the main line of the Severn & Wye at Tufts.
The lower coal measures were leased by Dyke to William Mullinger Higgins in March 1856.  These consisted of the Whittington and Coleford High Delf seams and in July 1857 the Bristol and Forest of Dean Coal Company Ltd., with which Higgins appears to have been connected, wrote to the Crown offices expressing their desire to sink shafts and erect steam engines on land alongside the Whitecroft to Bream road.  They also requested permission to construct a tramroad to join that laid by Dyke.  The Bristol and Forest of Dean Coal Company Ltd. was incorporated on 24th December 1856 with the aim of purchasing 'certain coal fields and collieries', the authorised capital was £25,000 in £1 shares.  Initially the registered office was in Bristol, from which city all the proprietors of the company came from, but by April 1857 it had moved to the Princess Royal Colliery.  The Managing Director was a Benjamin D. Collins from Breams Eaves.
In October 1857 the Bristol and Forest of Dean Coal Company informed the Crown that they were contemplating building three engine houses, a boiler house, an office and stores, a blacksmith's shop, a carpenter's shop and a stable and shed.  In December they wanted to add some miners' cottages and saught permission to dig clay on their land to enable them to make bricks.  There was, however, some difficulty in the Crown issueing leases for the above as the company were not the registered owners of the gale and consent for the works had to be gained from Dyke,  The consent to dig clay was finally obtained in March 1859, although there still appears to have been problems over the main lease as the Crown refused permission for the engine houses and warned that the buildings constructed already might have to be removed.
In July 1863 the Crown increased the royalty rate for Princess Royal to 3d. per ton.  The gale was now held by the Reverend William Dyke and his brother Henry who were the trustees of the estate of the late Thomas Dyke.  William Dyke thought that this increase, of 50%, was unreasonable, pointing out that the Yorkley seam could not be worked to any large extent in a profitable way.  The other two seams of coal in the gale had not yet been cut although a large sum of money had been expended.  He also pointed out that the whole of the works was at a stand and entirely unproductive.  The Crown in reply stated that Dyke was in fact letting the two lower seams to the Bristol and Forest of Dean Coal Company for £400 per year plus 8d. per ton on all coal raised.  Furthermore, he was letting a portion of the Yorkley seam to a Samuel Morgan at £240 per year plus a tonnage rate.  Dyke countered claiming he was removing the tramplates from the mouth of the level having abandoned any idea of profitable working.  He was also going to take the tonnage matter to arbitration, but the Crown won the day and the rate stayed at 3d!  Some of Dykes worries may have been caused by the fact that in February 1863 the Bristol and Forest of Dean Coal Co. was wound up under a petition from Charles Nash and Mark Whitwell, the company finally being dissolved in February 1866.  In early 1864, during the period that the company's affairs were being wound up by the Court of Chancery, William Dyke stated that he would like the lower measures to be surrendered to the Crown and that he would then apply for a fresh lease on them.
Some work obviously continued as in January 1865 the Gloucester Journal gives a report of a fatal accident at the colliery.  It would appear that the winding engine had broken down and that work had been suspended for several days leaving the problem of feeding the pit-ponies who were still underground.  One Charles Lewis volunteered to descend the shaft and carry out the necessary tasks and this was accomplished.  On the return up the shaft, however, the rope, which had been put on especially for the job broke when Lewis was within 14 yards of the top.  He fell between 40 and 50 yards to his death.  The manager of the colliery at this time was a Samuel Morgan.
By March 1866 the Princess Royal gale was in the hands of Messrs. Francis and Brain and in 1874 it was owned by the United Colliery Company whose manager was a Mr. Dunning.  They wished to lay a line of tramroad from Dyke's Level to a siding off the Severn & Wye main line near Whitecroft, but the Crown refused permission.  However in 1876 the Severn & Wye extended their Oakwood branch further along the course of Dyke's tramway to Dyke's Level, now also known as Whitecroft Level.  At this time Captain Ross was the sole owner of the Princess Royal gale, but in February 1887 he conveyed the ownership to William Camm and Richard Watkins, both of Bream.
This meant that the Princess Royal, Flour Mill and Prince of Wales gales were in the hands of Watkins and Camm.  The Princess Royal gale had been opened but was not being worked,  Flour Mill was being worked to a limited extent whilst Prince of Wales was unopened.  Watkins was hoping that the Crown would remove the barriers between the three gales and allow him to work them as one.  This, he ensured the Crown, could be done if he installed good pumping plant at Park Gutter and he had such machinery at Flour Mill which he would move.  The Crown were not so sure and wanted firmer assurances that the gales would be fully opened up before they would remove the barriers.  Watkins initially was not prepared to meet this condition as it would involve him in a great deal of capital outlay with no guarantee that the Crown would remove the barriers.  At this time Watkins was also leasing the Park Hill gale from Messrs. Crawshay and he was desirous of driving a cart way through that barrier as well, in order, he said, to improve the ventilation.  This permission the Crown was certainly not disposed to grant.
With regard to the conditions imposed by the Crown Watkins had to invest the sum of £5,000 before the barriers would be removed and it was to this end that he finally got a company formed to finance the work.
On 23 December 1890  the Princess Royal Colliery Co Ltd. was incorporated with a capital of £10,000 in £10 shares.  The company was to adopt an agreement made on 2nd December 1890 between Sir William Henry Marling Bart., Frederick Winterbotham, Richard Watkins and Charles Bailey for the sale and purchase of the Princess Royal, Flour Mill, Ellwood and Prince of Wales Collieries.  It would appear that prior to this agreement as well as mortgaging the colliery to Marling for the sum of £2,000 he also had an advance from Winterbotham.
In November 1890 it was reported that work was being pushed forward rapidly.  The provision of new railway sidings alongside the Park Gutter pits, and the necessary extension of the Oakwood branch, was well in hand and the new machinery and boilers were mostly erected with about £2,500 of the £5,000 being spent.  It was at this point that a problem arose in transfering the ownership of the gales to the new company.  The Gavellers records showed that Watkins and William Camm were the registered owners and that for any conveyance to take place the consent of both registered owners had to be given.  Camm now re-appeared on the scene and refused to give his permission but Watkins countered this by showing that he had been made solely liable for the mortgage debt and interest payments on a mortgage taken out in February 1887 with Sir W. H. Marling.  In November 1892 the company were re-opening the Flour Mill pits and wished to construct a rope worked tramway from Flour Mill to enable coal to be brought down to the new screens being built on the loading bank at Park Gutter.  In 1896 the Severn & Wye Co's. fence, which lay between the colliery company's tramway and the railway sidings was moved to the far side of the tramway as materials being loaded over the fence had damaged it!
When the company began to raise coal through the Park Gutter shafts in 1897 it became necessary to lay extra siding accommodation at the end of the Oakwood branch to deal with the anticipated extra 300-500 tons of coal per day.  The sidings were further altered in 1902 when a weighing machine was also installed.
For some reason yet to be ascertained the Princess Royal Colliery Co. Ltd. was wound up in June 1900 and in November a new company was registered.  This was the Princess Royal Colliery Co. Ltd. the new arrangements probably being just a restructuring of the old ones!
By February 1900 the company was considering sinking a new pit at Flour Mill down to the Trenchard coal and working the Diamond No. 2 gale which underlay Flour Mill.  Once this was completed one of the existing Flour Mill shafts was also to be deepened to the Trenchard.  One of the reasons for this was that the Flour Mill Colliery was working the coal from the bottom of the existing shaft, which was 190 yards deep, upwards towards the western boundary of the gale, almost to the outcrop of the seam.  It therefore became necessary to sink a new shaft, 140 yards deep and fourteen feet in diameter, which enabled the company to develop the dip of the seam.  The area they were working in, however, proved to be very heavily watered and required the pumping of up to 3,000 gallons per minute.  Later considerable geological difficulties were met and it became necessary for yet another shaft to be sunk.  As will be seen later this was overcome by deepening the shaft at Park Gutter.  Trial borings to the Trenchard were made but the seam proved uneconomic to work and so the new shaft was taken only as far as the Coleford High Delf.  The seam here was 4' 9" thick.This work was in hand in December 1903.
Soon after the passing of the Forest of Dean (Mines) Act of 1904 several gales were amalgamated to be worked by the Princess Royal Company.  These included Flour Mill, Princess Royal, Rising Sun Engine, Venus & Jupiter, Union, and the Princess of Wales, all of which were already owned by the company.  They also acquired High Delf Engine, Royal, Beaufort Engine, Skinners Garden and part of New United Deep No. 1.  All of the barriers within this area were to be abolished and a barrier of coal 30 yards wide was to be left all the way round the new perimeter.  Barriers had to be left between adjacent properties as a form of protection, both from influxes of water and encroachment by the adjoining works.  The dead rent for the whole of the new area was £1,200 per annum, but the royalty remained at 3d. per ton.  The company were to drive a dipple and a parallel airway forward in a straight line to the deepest part of the Coleford High Delf seam within their area.  To enable them to do this the Crown were to give financial assistance for pumping equipment if any undue quantity of water was encountered.
In 1905 the company reported that the Yorkley seam in the Park Gutter pits was being worked at a continuing loss, and thay they were only kept open for pumping purposes in order to keep the High Delf seam free of water at Flour Mill.
In 1906 increasing traffic from Princess Royal made further extensions to the siding accommodation necessary.  The loaded wagon road was extended to hold fifty vehicles, the screen roads were altered to provide an extra machine for weighing empties, and the wagon storage sidings were also lengthened to give a capacity of ninety-six.  All of these alterations were completed in 1908.
The Dean Forest Mercury  for 28th May 1909 gives a good description of the colliery and plant where a large capital investment programme was being undertaken especially at Flour Mill.  At this time Mr. Charles Cooke was the general manager, Mr. G. Lunn was underground manager, and Mr. T. Summers was the foreman at Flour Mill.  At Park Gutter 150 were employed getting house coal from the Yorkley seam which was two feet six inches thick.  The shafts were 100 yards deep but were only nine feet in diameter which caused some problems, especially in the pumping shaft, or water pit, where some peculiar practices were necessary.  The engine for this was the only one of its kind in the Forest and was a Hawthorn Davy compound condensing engine.  This operated two 19 inch diameter pumps and two 11 inch diameter bucket pumps.  There was also a 14 1/2  inch bucket set and their presence in the water pit reduced its diameter so much that no ordinary cage could go up and down and the bottom of the shaft had to be reached by a roadway from the winding shaft.  This shaft also contained a fifteen inch bucket set which was worked by a direct action fourteen foot cylinder and four foot cam arrangement.  The pumping capacity was equal to a maximum of 2,500 gallons per minute.  Steam was generated by three eight feet diameter by thirty feet Lancashire boilers.  There was no cage as such in the winding shaft but a simple device designed by Mr. Cooke was fitted on the wire rope guides used for holding the carts in the shaft.  Two stong iron bands dropped underneath the cart allowing them to be raised or lowered.
The main work of reconstuction was being carried out at Flour Mill where preparations were being made to work the colliery along modern lines.  By the date of the article some of the new works at Flour Mill were already in use and the developments were said to have changed the face of the Oakwood Valley.  The old Oakwood chemical works belonging to Messrs. Trotter of Coleford had been demolished and the large pond connected to them was being filled in.  The site of the old works was to be used for offices, workshops etc. which were in the course of construction.  A new, large power house had been built which was a substantial stone structure built on an eight foot bed of concrete.  The power house was 100 ft. long, 40 ft. wide and 25 ft. high to the eaves.  It was well ventilated and lit and at night there were three central arc lamps and a number of side lamps.  A ten ton capacity overhead crane ran its length to allow easy maintenance of the equipment.  This consisted of two sets of Bellis and Moorcombe's high speed electrical engines, one set of 350 kw. capacity running at 333 revolutions per minute and the second of 750 kw. running at 250 revolutions.  The first had three lines of compound engines whilst the second was a triple expansion.  All of the steam piping in the power house was encased in plannished steel sheets 12" in diameter.  The switchboard was provided by Westinghouse and had nine panels supplying a voltage of 3,300 for the pumps and head gear work and 550 for haulage work.  Space was left in the power house for a third generating set if necessary.  Outside the house a Westinghouse-Lablanc condenser was being erected together with four new Lancashire boilers, each 30' x 8' 6", working at 160 p.s.i. with superheaters.  There was also a set of Greens economisers.  To obviate the expenditure on a tall chimney stack to provide the draught for the boilers a small Marshall automatic engine and sirocco fan were used to induce a draught into the existing chimney although the foundations had been laid for a new stack if eventually needed.
The underground workings, which were accessed by a dipple from the new shaft bottom and new dipples had advanced about 300 yards.  It was hoped that coal would be being brought up the new shaft, which was 145 yards deep, in a single decked cage within a week or two.  The winding engine on this shaft was said to be 'an ordinary compressed steam winding engine'.
The underground steam haulage, a pair of 150 h.p. Fowler egines, were to be replaced by an electrically operated 250 h.p. Fowler haulage.  The original pumping plant, consisted of two of Messrs. F. Peams duplex pumps worked by a Cornish engine having a 52" diameter cylinder by 8' stroke.  This was fed by steam from five Lancashire boilers, three of which were 7' diameter by 30' and two 8' x 30', and two egg-enders 6' x 35'.  The new pumping power was to be was to be three high speed  five stage centrifugal pumps by Sulzer Bros.
Flour Mill Colliery suffered from a strike in October 1909 when six buttymen came out in dispute over the cutting of a pillar of coal.  The rest of the 700 men also came out and the pit ponies were put up for sale. The buttymen took the matter to Court but lost and the srike was over within the month.  A more serious strike was the national one of 1912 and it was after this shutdown that the decision was made to start work on the deepening of the Park Gutter shaft to assist the winning of coal from Flour Mill and to open up new areas of the Coleford High Delf as laid out in the 1904 arrangements.  Work commenced in stripping all of the old equipment out of the shaft in October 1913.  A new headframe was erected and new boilers installed in 1914, and on 12th August the following year the shaft reached the Coleford High Delf seam at a depth of 205 yards.  From the bottom of the shaft a main dipple was driven, as per the terms of the 1904 agreement, until an overall depth of 1,500 feet below the surface was reached.  Coal from the Yorkley and Coleford seams was then raised through this pit.
Flour Mill and Park Gutter were connected underground in early 1916 to provide efficient ventilation and to enable the start of coal production on a larger scale.  Some coal was still being brought up the middle shaft at Flour Mill until 1928, a peculiarity here being that the cages in the shaft were small and pit ponies had to sit on their haunches when entering them to be let down the shaft.
A scheme was mooted by the Princess Royal management in 1914 to build a works for converting coal into fuel oil, smokeless fuel and various by-products for use by the navy.  This was to be built on Crown land alongside the tramway to Flour Mill.  Negotiations with the Crown, who were worried about environmental damage, continued for several years, but eventually the idea was abandoned.
In 1922 the company erected new screens which, however, encroached upon Severn & Wye land, and for which no agreement had been reached.  Although the Joint Committee consented to their remaining, subject to a suitable agreement being entered into, it was discovered that the screens had insufficient clearance to allow the passage of box vans with stores for the colliery.  The Princess Royal management, showing considerable nerve, then approached the Joint Committee with a request to contribute towards the cost of additional siding accommodation to allow such vans to be dealt with and inprove the general working arrangements.  The Committee, not surprisingly, decided that the accommodation was solely for the convienience of the colliery company, and declined to assist.
In 1925 water from Norchard Colliery burst into Princess Royal and the company became involved in legal disputes with their neighbours.  This also raised the question of amalgamation of the two concerns and in 1930 the Princess Royal Colliery Company purchased a controlling interest in Norchard from Lord Bledisloe.  This enabled the whole of the southern area of the coalfield to be worked more economically, especially after the New Norchard slant had been driven to the surface at Pillowell in 1937.
In 1938 the steam winding engine at Park Gutter was replaced by an electric one, all of the pumping underground also being electrically powered, with the capacity to deal with 5,000 gallons per minute in winter.  The average quantity of water pumped was 2,700 gallons per minute, which was equivalent to twenty tons of water for each ton of coal produced.  In the 1930s the annual output of coal from the Coleford High Delf was about 300,000 tons.
When in 1944 the New Fancy Colliery closed Princess Royal was able to find employment for most of the 300 workmen.  In 1953 work was restarted in the Yorkley seam but due to bad conditions was stopped again in April 1958.  In 1955 it had been decided to drive another road between Princess Royal and Norchard, which had already been united in 1932 for ventilation purposes and other services.  This new link was to be a rock heading, 1,778 yards long, off which it was intended to open up a large area of the Coleford High Delf seam in the Howbeech area towards eastern United.  Coal faces were also being driven northwards towards Cannop Colliery, which closed in 1960.  However, the bad conditions met with in several areas, together with the increased pumping costs caused by the closure of Cannop, forced the decision to close.
Final closure took place on friday, 30th March 1962, although some coal was still screened at Park Gutter from the re-opened Pillowell shaft until 1965.  This coal was brought in by road and created enough traffic for two or three outward trains per week.  Part of Princess Royal was opened up to pump water from the Pillowell area, but in 1965 the cables in the Park Gutter shafts were cut and the cages allowed to fall to the bottom.
At its peak Princess Royal had employed 1,300 men and had an output of up to 1,000 tons per day.