The Trafalgar gale was granted in August 1842 to Corneleus Brain of Mitcheldean and was to remain in the possession of the Brain family until 1919.  It would appear that work did not commence at Trafalgar until around 1860 although it must be said that details of the early history of the concern are few and far between.
Since at least 1847 Corneleus and Francis Brain had been lessees of the Rose-in-Hand gale and in 1867 they obtained a Crown licence to work the barrier between that gale and the Trafalgar gale.  This meant that the two gales effectively became one for the purpose of working the coal which would undoubtedly have been raised via the shafts at Trafalgar.  No record of a shaft or level on Rose-in-Hand has been found, coal from here previous to 1867 having been brought to the surface through Royal Forester gale which later formed part of Speech House Hill Colliery.
It is also possible that at around this time the Brains acquired the New Strip-and-at-it Colliery which lay adjacent to Trafalgar.  Strip-and-at-it was a concern which had already been worked for a considerable period.  The 1841 Awards of Coal and Iron Mines stated that a John Harris had been working Strip-and-at-it since April 1832 although his application for the gale had been rejected.  The gale had, however, been surrendered to the Crown in 1864 and was then acquired by the Brains. Strip-and-at-it had been connected to the Churchway branch of the Severn & Wye tramroad in 1842 and, with the commencement of operations at Trafalgar in 1860, permission was gained for a connection to the Strip-and-at-it spur, the new line including a short tunnel.
At Trafalgar itself there were two shafts down to the Churchway High Delf seam at a depth of 195 yards.  They were between 30 and 40 yards apart and worked by the same winding engine, with coal coming up one and empties being lowered down the other.  One shaft was the downcast, where fresh air went down into the workings, and the other had a kind of bonnet fitted over the tacklers which covered the top of the land pit so that very little air was lost.  The main upcast shaft was called Puzzle, as the pit had been driven up-hill to the surface.
The cage was guided down the shaft by wooden guides running inside metal shoes on the side of the cage.  Wooden guides were used on both pits.  Ten men and boys could ride in each cage.
A report in the Gloucester Journal  in February 1867 tells how in working the ëlarge vein of coalí at the colliery the declavity was so great that the ordinary method of hauling to the bottom of the shaft, presumably horse or man power, was impracticable.  Corneleusí son William Blanch Brain, the colliery engineer therefore erected a small winding engine on the surface close to the pitís mouth in order to draw the loaded carts from the coal face to the bottom of the shaft.  The carts were connected to a long chain which ran to the far extremities of the workings.  Initially the great drawback was the delay in communication between the coal face and the pit bank when hauling was required so W. B. Brain who was also an electrician procured a pair of electric bells and placed one in the winding engine house and the other at the top of the ëdippleí or haulage road.  Several tappers were then placed along the road allowing the men in any part of the works to signal for the starting or stopping of the haulage engine.  The bell at the top of the dipple kept the men at pit bottom informed as to what was happening.  The success of the system was such that communication between pit bottom and the main winding engineman was also electrified.  At pit bottom a pair of tappers, one white and one red, were provided and on touching the white one a bell in the engine room sounded and the words ëgo oní appeared on the dial plate attached.  On touching the red the word ëstopí was shown.
Electrical communication was also used on the surface enabling W. B. Brain in his office to be kept in touch with the happenings at the pit.  Another snippet mentioned in the article was that a patent pump was in use at the colliery which instead of throwing successive stream of water threw a continuous one.
Trafalgar appears to have been unique amongst Forest collieries in that it was gas-lit underground, this only being possible due to the coalfield's freedom from gas or firedamp.  A Dean Forest Guardian report of a visit by Captain and Mrs. Wemyss to Trafalgar in October 1874 reads:

. . . that with Mr. T. B. Brain descended the shaft in the ordinary skip.  In this subterranean passage the visitors had not calculated upon finding the roadways lighted with gas similar to that employed in the lighting of streets and dwellings and were agreeably surprised to find instead of impenetrable darkness, the workings clearly defined from the jet burners which were dotted about the roadways . . . It may be of interest to add that the gas is forced down the shaft by means of a one horse horizontal engine
erected in the gas house at the pit bank.

The gas house is the building shown on the 1898 Severn & Wye plans containing a circular structure.
Another account of the gas illumination at Trafalgar comes from a guide book by John Bellows of Gloucester called A Week's Holiday in the Forest of Dean and published around 1880. It also gives some details of the surface workings and other facts about Trafalgar.

Before going down (underground) we may as well look at the large sandstone quarry on the premises where stones are cut for supporting the galleries below.  Let us pass through the tramway tunnel, 150 yards long, cut through the ridge of the hilltop, to a shaft on the other side.  This narrow ridge is the outcrop of the measures, and in the tunnel we can examine, rock, clod and duns, and a little thin coal with rock again below it. Having seen this we turn back again, enter the cage, and, closing our eyes to avoid the giddiness, are lowered 600 feet so smoothly, that we are hardly conscious of motion.  At the bottom we go into the underground office, and are supplied with a little brass lamp, and a bunch of cotton waste to wipe our hands upon, and then attended by 'the bailey' enter one of the main roadways...
... Where necessary, the underground workings are lighted with gas, and one of the partners, Mr. William Brain, is now preparing to adopt the electric light (which is already in use on the surface at night) and also to utilise electricity as a motive power at many of the underground inclines, or dipples, in the colliery, where steam is not available; and thus save many horses.  There are more than forty horses living in this pit.  They never return to daylight until worn out or disabled. Some of them have been down here a dozen years, and are in excellent health.
Fire damp is wholly unknown in the Forest of Dean, and miners work with naked lights. Choke damp breaks in rarely, and seldom gives any trouble.  The pit is remarkably free from water, and being furnished with every known appliance, and most admirably kept, is probably one of the best in the Forest, or out of it.  Eleven hundred men and boys are employed here: 600 underground getting coal, and 500 as labourers &c., above ground, and in subsidiary occupations.  Good colliers earn, at present, 3s 8d per day; masons 3s 4d; and labourers, 2s 4d.  One can hardly imagine anything more severe in the way of labour than that of a miner lying on his side in a four foot passage, cutting away with his pick the hard rock encasing the seam ...
... The output from Trafalgar, at the moment we are writing, which is a dull season is seven hundred tons of coal per day.

The foregoing passage gives a reasonable account of Trafalgar Colliery and is also notable in mentioning once again the use of electricity at the pit.
Francis William Thomas (Frank) Brain had been associated with the use of electric floodlights on the Severn Bridge in 1879 where they had been used to enable construction work to continue at night to make the best use of the tides. After use on the bridge, the apparatus, consisting of a couple of powerful lamps supplied by a Gramme machine, was re-erected at Trafalgar on the surface to light the colliery yard, and a football match was even played at night! Frank Brain was also connected with the Electric Blasting Apparatus Company who made fuses for simultaneous shot firing underground, and had buildings close to Trafalgar Colliery.
Electricity was also used at Trafalgar when the first underground pumping plant was installed in December 1882.  The installation at Trafalgar was the first recorded use of electric power in mines. The equipment consisted of a Gramme machine on the surface driven by a steam engine and a Siemens dynamo used as a 11/2 horse power motor belted to a pump underground. The Gramme machine still exists today, preserved in the National Museum of Wales in Cardiff.  It attained such success that three additional plants were erected in May 1887 and these did the larger part of the pumping.  The last installation consisted of a double-throw nine inch plunger, by ten inch stoke, situated 2,200 yards from the generator and 1,650 yards from the bottom of the shaft.  The pipe main was seven inches in diameter and at its maximum speed of twenty-five strokes a minute the pump lifted 120 gallons to a height of 300 feet.  The current was conveyed to the motor by an 13/16 copper wire carried on earthenware cups.  The E.M.F. was 320 volts and the current required was 43 amperes.  The installation cost of the engine and the electrical plant was £644, whilst the weekly cost for maintenance, including 15% for depreciation and interest on capital was £7 17s. or .002d. per horse power per hour.  The efficiency attained throughout was only 35% but the engine which was an old one lost 6.49 horse power, or 22% alone.  If this was removed from the equation then the efficiency was 45%.
During this period the ownership of Trafalgar changed when the Trafalgar Colliery Co. Ltd. was formed to carry out an agreement dated 22 December 1883.  This was between Thomas Bennett Brain and William Blanch Brain for the Trafalgar Company; John Lysaght and William Sutcliffe Ogden for the Wye Colliery Co, the lessees of Speculation Colliery; and a Charles Bailey on behalf of the new company for the sale and purchase of both Trafalgar and Speculation Collieries.
The capital of the new company was £66,000 in 6,600 £10 shares of which 5,000 were to be issued in equal shares to T. B. and W. B.  Brain in payment for Trafalgar.  A further 1,000 shares were to go to Lysaght and Ogden in respect of Speculation.
The new limited company was incorporated on 22 December 1883.  The first directors were the Brains, Lysaght, Ogden and James Smith, a colliery proprietor of Stroud, who held two hundred shares.  The shareholding of W. B. Brain diminished rapidly as he had raised a £5,000 mortgage on his house, St. Annalls, in Cinderford and to offset this he was to allot 500 fully paid up shares in the company to Lindsey W. Winterbotham, a Stroud solicitor, and a Ferdinando Stratford Collins of Ross.  A further 3,000 of T.B. and W. B. Brains shares were to be given to a trustee for the Gloucestershire Banking Co. in lieu of a joint debt.  This transaction would reduce the debt to £20,000.  From these various transactions it would appear that the main reason for the formation of the new company was to protect it from being taken out of the hands of the Brain family by creditors.  The connection with the Wye Colliery Co. and the Speculation Colliery was that the Wye Colliery Co. could not continue business as the existing mortgages  exceeded the value of the property.
Trafalgar was connected to the Severn & Wye at a point between Serridge Junction and Drybrook Road station. The sidings to the screens stemmed from a loop off the main line on the 'down' side. They were laid soon after the Mineral Loop was constructed, Trafalgar Colliery being one of those which it was intended to serve. Agreement was reached in July 1872 for a siding to be put in, the S & W sharing the cost with the colliery, and by November the following year the S & W's chairman and engineer were able to observe 'the effective working of the new coal screens at Trafalgar Colliery which are well reported of'.
Prior to the construction of the Loop, however, Trafalgar was connected to the Great Western Railway at Bilson by a 2' 71/2" gauge tramway, known locally as Brain's Tramway .  The single line of edge rails laid on wooden sleepers ran east from the colliery, turning south-east at Laymoor, and terminated 1l/2 miles away at interchange sidings at Bilson. It would appear that the authorisation for its construction was a Crown licence for 'a road or tramway 15 feet broad' dated May 1862. The date the line was opened for traffic is unknown as, although the first of three locomotives used on the tramway was built in 1869, it is possible that it may have been horse worked before this date.
Traffic continued unhindered on the line, with a locomotive hauling 20-25 trams of coal on each trip, until 1872 when the Severn & Wye built their branch to Bilson. This crossed the tramway on the level near Laymoor and it was this crossing which caused problems when the Severn & Wye extended beyond Drybrook Road.  When passenger trains began running over it in August 1878, the increased traffic prompted the Brains to complain to the Severn &Wye in November of 'the hindrance and danger to their traffic on the trolley road at its crossing of the Bilson branch'.
Despite this small antagonism, the tramway settled down to a period of peaceful co-existence with the Severn & Wye until, in 1885, the latter decided that far too much of Trafalgar's output was reaching the Great Western over the tramway. An approach was made to the colliery company to provide arrangements for loading hand picked nut coal on the Severn & Wye sidings as well as on the Great Western at Bilson. This was rejected at first but by January 1887, after further negotiations, Trafalgar approved a proposal whereby the Severn & Wye altered the sidings and shed whilst the colliery company altered the screens, thus resolving this 'vexed question'.
Finally, in December 1889, an agreement was entered into between the Severn & Wye and the Trafalgar Colliery Company who, it was said, 'are desirous of obtaining railway communication to Bilson Junction in lieu of their existing trolley road.'
It was agreed that on or before 31 March 1890 the colliery company would construct new sidings and the railway company would lay in a new junction at Drybrook Road. Although the new junction was a quarter of a mile closer to Drybrook Road than the old sidings, the mileage charge was to remain the same.  The accommodation, on approximately the same level as Drybrook Road station, was to be constructed so that traffic to and from the Great Western would be placed on a different siding to that which was to pass over the Severn & Wye system. For taking traffic to Bilson Junction for transfer to the Great Western the colliery was to be charged 7d per loaded wagon, although empties were to pass free. The transfer traffic also had to be conveyed 'at reasonable times and in fair quantities so as to fit in with the ordinary workings of the Railway Company trains'.
The new sidings were brought into use on 1st October 1890 and a circular sent out by the Trafalgar management to traders read:

We have now completed extensive alterations and in future all coal will be loaded by means of improved screens erected at the pits mouth.
It will facilitate our arrangements and ensure the most prompt attention possible if customers will please label their trucks via Severn Bridge and Lydney Junction ó Severn and Wye Railway.

As to the working of the sidings, the 1894 Severn & Wye rule book stipulated:

1st. The Main Line Train on arriving at Drybrook Road Junction is to place the Empties into the left hand Siding, and, if the road is clear, to push them on as far as desired by the Colliery Company, provided there is no delay.

2nd. Take out to Drybrook Road Junction all wagons, the loaded and weighed, for the Severn & Wye & Severn Bridge Railway; but, if the load is too heavy, the Wagons left behind must be drawn down to the lower end of the Siding, so as to leave the upper portion of the Siding free for the Colliery to weigh and place their Wagons.

3rd. Take out the Wagons loaded for the Great Western Railway to Bilson; returning with the Empties to Trafalgar and placing them as before.

4th. Take out to Drybrook Road Junction the remainder of the Wagons then loaded and weighed for the Severn & Wye & Severn Bridge Railway.

Following the abandonment of the stretch of Brain's Tramway from Laymoor to Bilson Junction, two of the locomotives were put up for sale. An advertisement in the Colliery Guardian, 2nd January 1891, read: 'For sale, in consequence of abandonment of pit cart railway, two 6-wheeled locomotives, built by Lilleshall Iron Co. Copper fireboxes, brass tubes. Good working order.' The two locomotives concerned appear to have been Trafalgar (built 1869) and The Brothers  (1870); both were 0ó4ó2 side tanks with 8 x 14 in. outside cylinders and valve gear. The sale, however, did not go through and both locomotives remained at Trafalgar until broken up.
Trafalgar  was in fact in use until 1906 working on the northern extension of the tramway, built in 1869, to the Golden Valley Iron Mine at Drybrook.  The third locomotive was Free Miner  which is also believed to have been built by Lilleshall, but as an 0ó4ó0.
The level crossing over the Severn & Wye at Laymoor was undoubtedly removed soon after 1890, together with the stretch of line to Bilson Yard. However, this isolated the colliery locomotives from their water supply which had been gained from Laymoor Well.  To preserve the facility, pipes were laid under the Severn & Wye to a brick water tank on the north side of the railway. It would appear, however, that this tank was out of use by 1897.
Returning to the affairs of the colliery itself, it seems that by 1913 difficulties were being encountered with water. The managements of both Foxes Bridge and Lightmoor Collieries were worried about the threatened abandonment of Trafalgar; it was feared that if pumping ceased, their own collieries might be under threat from the build-up of water within Trafalgar's workings.  The colliery was offered for sale to Crawshay's, the owners of Lightmoor and with an interest in Foxes Bridge, but at a figure they would not entertain.
At the beginning of 1919 the main dip roadway at Trafalgar was suddenly, and unexpectedly, flooded.  A report in the Gloucester Journal  on 25 January stated that as a result of the flooding 450 men were temporarily unemployed.  Apparently the electric pump, which had drained the deep workings for over 30 years, failed.  On the evening of Saturday 11th the hold in which the water gathered was left empty but on the Sunday morning the pumpsman found not only the hold full but also the pumphouse.  During the day attempts were made to start the pump but on Sunday night it became drowned and unworkable.  Water then began to rise and threatened the ventilation of the entire colliery.  A pump was borrowed from Norchard Colliery and this was put down the pit on Monday night but by this time the air had become severely affected.  Every effort was made to get the relief pump working but then came a serious inrush of black damp and it became too dangerous for the men to continue work in the area.  By Thursday the colliery had to be completely closed and steps were taken to ventilate the whole workings.  The flooding once again led to worries by the Foxes Bridge and Lightmoor managements  about the dangers to their concerns.  Trafalgar was now offered for sale at £16,000. The Foxes Bridge and Lightmoor managements were prepared to offer £10,000 and, in an attempt to meet the difference, the Crown agreed to provide £4,000 should the sale go through.  It was estimated at this time that there was still 21/2 million tons of coal to be worked in the pit and its associated gales which would give the Crown an annual return from tonnage rates of £1,000 for 20 years, certainly paying back the £4,000.
On 4th November 1919 the transfer of the Trafalgar Colliery Co. Ltd. by Sir Francis Brain to Henry Crawshay & Co. Ltd. (represented by Edwin William Morgan) and the Foxes Bridge Colliery Co. Ltd. (represented by Arthur John Morgan) was completed.
The new management obviously continued to work coal from Trafalgar as a total of 4,729 tons were shipped via Lydney and Sharpness in 1923. However, in December of that year it was reported that the colliery was in difficulties for an area of coal to work. An application was made to the Crown to work the barrier between Trafalgar and Foxes Bridge but this was refused.
In December 1923  there were press reports of the formation of the New Trafalgar Colliery Co. Ltd. which it was said had taken over the Speculation, Rose-in-Hand, Twenty Inches and Trafalgar gales from H. Crawshay and the Foxes Bridge Co. It was a private company set up to take over Trafalgar as a going concern.  It had a nominal capital of £30,000 in £1 shares.  The directors were Capt. J. W. Braser Creagh; F. N. Wasbourne; R. C. Heyworth; Major L. C. Bucknell; A.J. Morgan; Capt. R. E. Richardson; & Dr. D. A. Davies.  The qualification of directors was to be the holding of the necessary number of either H. Crawshay & Co. Ltd. or of the Foxes Bridge Colliery Co. Ltd. shares.  Effectively therefore the New Trafalgar Colliery Co. Ltd. was a satellite company of Henry Crawshay & Co. Ltd.   However in August 1924, it was reported to Crawshay's shareholders that Trafalgar was to be abandoned. This would have affected 300 employees, but it was said that the blow would be tempered by a long spell of under-employment as latterly only one day a week had been worked.
Nothing appears to have happened immediately as in June 1925 it was reported that, due to huge accumulated losses, Trafalgar was likely to close in the near future.  On 14 August a report appeared in the Dean Forest Mercury  that notices to terminate the employment of the workforce would be served the following Monday (the 17th).
The final details of the closure are uncertain.  It seems that the colliery closed the following month, September, the private siding agreement being terminated at the same time.  It may have been that pumping continued for a while but was interrupted by the coal strike in 1926, one report stating that upon the conclusion of the strike the workings were found to be flooded.  The effects of the colliery were sold off by auctions between 1925 and 1927.