Thornley colliery began to draw coals in 1834. The Harvey seam would then probably not be extensively worked, but in 1858 the workings had reached a considerable extent in all directions. The coals were brought to the shaft by a hauling-engine and boiler, both placed underground the boiler-flue being made in the coal-seam.

In June 1858, the coal adjoining the flue-way took fire, and it was found necessary to drown it out and a considerable quantity of water ran into the face of the east headways district, at that time being driven in the whole mine (Fig. 1, Plate III.). There would probably be no opportunity of surveying the face of this district, although the plan might be drawn, roughly, by making use of such information as was then available. The south way, out of the east headways, continued working until 1881, when the Harvey seam was laid in. There would probably be an opportunity of surveying the south way and other districts, which were abandoned either at this date, or previously, except the east headways, and of having the plans of the workings completed to the extreme extent of the workings, although there can be no certainty if this having been done. After the seam was laid in, the water in the east headways gradually rose, until it closed all connections with the south way, leaving the higher workings of the south way water-sealed but dry.

The Harvey seam has always made a considerable quantity of gas, and this, at intervals. burst out of the south way, through the water, and towards the shaft. This gas is supposed to have been the cause of an explosion, which occurred in the downcast shaft, on August 23rd, 1865.

On May 8th, 1875, a disastrous fire practically destroyed all the surface-plant, and timber in the shaft. The feeders of water which had previously been pumped to bank, were necessarily allowed for a time to run into the workings of the Harvey seam, which had up to this date, with the exception of the east side, been kept clear of water. No further attempt was made to keep down this water, and the downcast shaft, below the Hutton seam, was blocked with debris from the fire. On March 24th, 1881, the water had risen to a level of 53½ feet below the Hutton seam. On April 23rd, 1888, to 47 feet below and on December 8th, 1884, to 43½ feet below that seam (Fig. 2, Plate III.).

After the fire, the downcast shaft was filled with stones and other rubbish, to about 25 feet below the level of the Hutton seam. It is supposed that this was done, because there was a risk of the gas from the Harvey seam escaping into the shaft through the water and debris.

Between 1884 and 1887, all operations at Thornley colliery were suspended. Meanwhile, the water rose above the level of the Main coal-seam, to an altitude of about 120 feet below sea-level.

On May 11th, 1888, a commencement was made to draw the water with water-cages. On February 9th, 1889, the water was lowered to the level of the Hutton seam hanging-on, and was afterwards lowered to about 20 feet below this level (Fig. 2, Plate III.). The water has since been maintained about this point although it was never lowered to the same level in the upcast staple between the Harvey and Hutton seams, but stood about 14 feet below the level of the Hutton seam, until disturbed by the operation about to be described in this paper.

The Harvey seam at Wheatley Hill colliery was first worked in 1892 ; and in 1894, some of the working-places in the northwest district began to show signs of water. This, taking into consideration the proximity of the drowned workings of the Harvey seam of Thornley colliery, was rather alarming, although the Wheatley Hill workings were still, according to the plans, about 525 feet from the nearest workings of Thornley colliery in the Harvey seam. The working-places where the water had made its appearance were stopped, and it was decided to leave a barrier of at least 450 feet of solid coal against the workings of the Harvey seam of Thornley colliery, as delineated on the plan, as it was possible that this plan was incomplete.

Early in 1900, it was decided to hole into the Thornley workings from Wheatley Hill colliery, so as to run off the water to the Wheatley Hill pit, through the Burnside safety-boring apparatus.

A vertical hole was drilled from the Busty seam of Wheatley Hill colliery, at a point where a little water was made at a crack in the roof, lying in the same course as the edge of the goaf in the overlying Harvey seam of Thornley colliery, and in the face of a place, A, which had previously been driven a few feet under the goaf for this purpose 1 and 2, Plate III.). This hole penetrated the goaf on 3rd, 1900, but as the goaf was close, only a very little water came away, with a little gas. The hole was then plugged and left.

A narrow headway, BCD (8 feet wide), was then driven, with bore-holes, from the north-west district of the Harvey seam of Wheatley Hill colliery in the direction of the east headways of Thornley colliery: this was the lowest point of the Thornley workings (Figs. 1, 2 and 3, Plate III.).

The bore-holes were drilled with a hand-rotated stone-drilling machine of suitable height, constructed so that the feed-worm and nut might be quickly released, and the rods withdrawn through the stand of the machine. The feed-worm had a Whitworth thread, 6 turns to the inch, 1 3/8 inches in diameter, the screw being 2 feet 7½ inches long. The boring-machine had a double handle, with a 12-inch throw, and was worked by two men turning together. Ratchets were only used when going through a piece of pyrites, and this did not often occur (Figs. 4 and 5, Plate IV.).

The Burnside safety-boring apparatus consists of the tube which is wedged into the hole ; the wedges and the necessary taps and glands outside the hole. Special drills are used to enlarge the outer end of the bore-hole to the necessary diameter so as to admit the tube and wedges ; and bore-rods of round section, may be added, as the hole advances, without opening the apparatus.

The hole is drilled of the diameter, it is intended to continue, for a length of about 5 feet. A length of 3¼ feet is then enlarged with the intermediate drill (Figs. 7 and 8, Plate IV.), and 2 feet 10 inches of this hole is again enlarged with the large drill (Fig. 9, Plate IV.), leaving a shoulder C, against which the water-tight joint is made (Figs. 4 and 5, Plate IV.).

A thick india-rubber washer is placed on the end of the tube against the flange, C, and the four wedges and the machine are pushed carefully into the hole, the upper and lower wedges, E, E, being placed with their heads against the flange, D; and the side-wedges, G, G, are fixed against the flange, C. When the india-rubber washer reaches the shoulder, C, left by the large drill, the upper and lower wedges are driven in with a hammer, and the side-wedges are drawn outward by turning the nuts, U, on the bolts, V, fitted for this purpose. While the side-wedges, G, G, are being drawn out, the tube moves into the hole for a certain distance, and compresses the india-rubber washer. This compression can be assisted also by setting the drilling-machine, and pressing the apparatus into the hole with the feed-worm (Figs. 4 and 5, Plate IV.).

The apparatus, when set, can be tested by means of the hydraulic test-pump (Fig. 14), and pressure-gauge, H (Fig. 4) ; and if well set there will be practically no leakage of water or gas at a pressure of 200 pounds per square inch. The test-pump may be fitted either upon the gland, M, or the tap, N; but the pump, as supplied with the apparatus, will only work efficiently in a vertical position, owing to the valves with which it is fitted (Figs. 4 and 5, Plate IV.).

The tap, N, may be left open while drilling a horizontal hole in order that the drillings may escape, if there be sufficient water to bring them out, and the tap, P, may be used for the same purpose in the case of a vertical hole (Fig. 4, Plate IV.).

It any other section of rods than the round section, supplied with the machine, be used, these rods should be added next to the piston-rod, R (Figs. 4 and 5, Plate IV.), so as to keep this piece working through the gland, M, and next to the feed-worm. In this case, it will be necessary to open the gland, M, every time another rod is added.

If the round section of rods be used, they may be added outside the apparatus, between the feed-worm and the piston-rod, R : and it is then only necessary to open the gland, M, when changing a drill; or, if the drill be not clearing itself, to remove the debris.

At T T, are pieces of india-rubber, which can be screwed against the rods, and these will, if necessary, make the apparatus almost water-tight, even when the gland, M, is open. This arrangement is adopted so as to guard against the possibility of water breaking away while the rods are being withdrawn, for any reason, from the hole. The large tap, L, can only be closed when the rods are drawn out of the apparatus. The gland, M, makes a gas and water-tight joint with the round rods, or the piston-rod, R. The barrel and taps of the apparatus are made of gun-metal, and the wedges, etc., of iron.

The chief advantages of the Burnside safety-boring apparatus are — (1) The comparative ease and quickness with which it can be securely set, or withdrawn. (2) It can be tested with the hydraulic pump, before proceeding to bore. (3) The remarkably small leakage of water and gas when the apparatus is well set. (4) If any taps are for any reason left open, when the rods hole, they can be easily closed. (5) The - ease with which pipes, to conduct the water away, can be connected to the machine, when necessary.

The writer found, in holes 54 feet long, that two men drilled an average length of 48 feet in a shift.

In the first length of 348 feet of the headways, 8 feet wide, B C, the flank-holes were drilled at intervals of 9 feet, at an angle of 30 degrees from the line of the place, alternately 27 feet and 54 feet long; and the straight-on hole was kept 54 feet in advance of the coal-face (Fig. 3 Plate III.). For the remaining length of 132 feet, C D, previous to the holing, the flank-holes were made 54 feet long. In the south-east headways district of Thornley colliery, the bords were driven 12 to 15 feet wide, and the walls 7 or 8 feet wide.

Considerable difficulty was, at first, experienced in boring holes as long as was desired, without their penetrating into the roof of the seam. The holes were, at first, set away about the middle of the seam, for convenience in turning the handle, and having the same rising inclination as the seam ; but it was soon found desirable to incline the holes slightly towards the bottom of the seam and even these holes penetrated into the roof-stone more frequently than into the bottom-stone, if continued far enough, but few holes got either into top or bottom stone within 40 feet. The seam is about 3 feet 8 inches thick.

Very few of the straight-on holes were lost through deviating to either side of the place. Some of the straight-on holes were continued as the face advanced, to a total length of more than 100 feet: 95 feet being the greatest length on any hole at any one time.

The tendency of the holes to rise into the roof may have been due to the cutting-edge of the drill being larger in diameter than the rods (Fig. 5, Plate IV.). The rods would of their own weight lie along the bottom of the hole, while the centre of the drill would be in the centre of the far end of the hole; this position would give to the drill and the last few rods a slight upward inclination, and would continually tend to cause the hole to rise towards the roof.

When the drill encountered pyrites or any other irregularity in the seam, the holes were diverted from their course in any direction, sometimes so great that the rods would hardly follow the new line of the hole.

In the beginning, the Burnside safety-boring apparatus was wedged into every hole, and this took a considerable time : moreover, if a hole was not bored to its distance at the end of the borer's shift, the apparatus had to be removed out of the way of the coal-hewers and afterwards reset on the same hole. It was therefore decided only to use the Burnside apparatus in holes, showing signs of water; consequently it was only set two or three times before September 13th, 1900, when a straight-on hole, which had so far not been unusually damp, reached a breaker in the coal, E, and encountered a feeder of about 10 gallons of water per minute (Fig. 3, Plate III). This hole happened to be 67 feet long, as the flank-holes were not due to be bored, and the borers had therefore continued the straight-on hole past its usual distance.

After setting the apparatus on this hole and closing it, the pressure in a few minutes rose to 85 pounds per square inch, which agreed, at the time, with the level of the water in the Harvey staple at Thornley colliery. There was a dropping of water at one or two of the glands and a very slight leakage out of the hole, and the total leakage may be estimated at less than 1 quart of water in the hour; and this speaks strongly for the utility of the apparatus, which had been in the pit for some months, and had been used several times previously. The apparatus was left in the hole until a cistern was set, and pipes laid from the cistern, to conduct the water to the standage.

On September 20th, 1900, the taps were turned on, but the quantity of water did not increase as was expected, and on the following day the hole was bored another foot, through the Burnside machine. This produced more water than the cistern and pipes would carry away — probably about 60 gallons per minute — and the taps were set so as to allow of the issue of about 40 gallons per minute — the full carrying capacity of the pipes (Fig. 15, Plate V.).

This quantity not being so large as was desired, on September 26th the cistern being removed, the apparatus was coupled direct to the pipes, and the tap on the machine opened to its full extent. The water then increased to about 50 gallons per minute. As this feeder was still not considered sufficient, the rods were again put through the machine, on October 11th, and the hole bored a further 3 feet. This gave a further increase of water, to about 80 gallons per minute.

This feeder then slowly became less, probably due to loss of pressure, and on November 10th, although it was thought that the hole was bored through, the rods were again put in, and 2 feet farther bored to F, still in broken coal (Fig. 3, Plate III.). The water then came away with great force, clearly showing that the hole was through, and that it had not previously been so. The quantity of water running through the pipes then increased to 140 gallons per minute, while the pressure indicated at the Burnside machine was 45 pounds per square inch, when the water was running.

The range of pipes by which the water was conducted from the machine was connected to the tap, N, 1½ inches in diameter, on the under side of the machine (Fig. 4, Plate IV.). The range consisted of 12 feet of pipes 2¼ inches in diameter, next the apparatus ; 216 feet of pipes, 8 inches in diameter and 2,100 feet of pipes, 4 inches in diameter : giving a total length of 2,328 feet.

On November 28th a second connection was made with the machine, by laying a range of pipes consisting of: 12 feet of pipes 1½ inches in diameter, and 216 feet of pipes 4 inches in diameter, and connecting it to the fore-end of the machine, and to the first range at the point where the pipes 3 inches and 4 inches respectively in diameter were connected together. The quantity of water, which had fallen to 108 gallons per minute was increased to 145 gallons, and the pressure which had already receded to 39 pounds, was further reduced to 28 pounds per square inch. The level of the water in the Harvey seam staple had lowered considerably by this date (Fig. 15, Plate V.).

As the water lowered down the staple, water-blasts were feared, but beyond the slow lowering of the water, which varied very much with the barometer, no change took place until January 24th, 1901, when the water was only 26 feet above the thill of the Harvey seam. At this date, a considerable quantity of gas began to be given off in the staple, with a faint rumbling noise, the surface of the water became disturbed, and the float, with which the level of the water was measured, rose and fell as much as 6 inches, 3 or 4 times a minute. On February 11th, 1901, the float reached some debris, 13 feet above the bottom of the staple; and on February 15th the rumbling noise was heard for the last time.

After the float reached the debris, it was still possible to obtain a fair idea as to the extent of the drainage of the Thornley workings by drawing a contour-line across the plan at a level corresponding to the pressure indicated at the Burnside apparatus, when the taps were turned off. This was done periodically until May 25th, 1901, at which date no pressure was indicated and the water-feeder had diminished to 35 gallons per minute, probably due to the feeders made in, and escaping down, the Thornley shaft and Harvey staple, together with a little drainage from the Harvey seam

Previous to this, a final attempt had been made on May 21st 1901, to get more water by boring the hole further; the rods travelled 7 feet in soft material, and at a total length of 80 feet they again encountered a hard substance. This was followed by no increase of water.

On June 13th, 1901, the boring-apparatus was withdrawn, and a few days later the headways was again set away, the boreholes being continued. Several more bore-holes were put through into the Thornley workings, and on July 11th, a coal-hewer holed into a narrow headways (Fig. 3, Plate III.). The headways was partially open at the holing, but it was quite close a few feet away Very little gas was evolved, and very little air travelled in either direction through the holing.

The water, particularly when it first came away, had a distinctly soapy feeling and a sickly taste ; and when first relieved from the pressure, it was white, but it quickly became clear, without any visible deposit being formed. The temporary whiteness was probably caused by gases escaping from solution, on account of the reduction of pressure. The water left a white slimy deposit wherever it flowed, for a distance of about 360 feet from the pipe-end ; beyond this point there was a thin red ochreous deposit for a short distance. There was no white deposit in the pipes, only a thin black scale, and no white deposit was found in the Thornley workings.

The water had a strong smell of sulphuretted hydrogen, and at the pipe-end a large quantity of gas issued with the water. There would probably be some methane, but the sulphuretted hydrogen was most prominent. The writer could devise no method of proving either the presence or absence of methane, as the action of sulphuretted hydrogen on a flame is similar to that of methane. The sulphuretted hydrogen was easily recognized by its odour, and by its action on test-papers impregnated with a solution of lead acetate and dried: these papers were quickly turned black when placed near the pipe-end. Sulphuretted hydrogen is the only gas that will turn lead acetate into lead sulphide.

Blue-litmus papers were turned of a reddish tint at the pipe-end.

The cap produced on a Marsaut-lamp flame, at the pipe-end, was much more blue than the usual fire-damp cap. There was no dimming of the flame, as might have been expected had any carbon dioxide been present.

The white slimy deposit left by the water largely consisted of sulphur, precipitated through the sulphuretted hydrogen being partially oxidized by the air. This deposition of sulphur usually takes place when a solution of sulphuretted hydrogen in water is exposed to the air, and the water in flowing over the rough bottom would facilitate this action.

The water originally came partly from the workings in the Low Main seam of Thornley colliery, and some of these water-feeders are salt.

About 4 years ago, the writer exposed some lead-acetate test-papers at the top of the Harvey staple, and detected the presence of sulphuretted hydrogen.

At times, with a low barometer, gas bubbled out of the water in the Harvey staple, but more usually the gas rose from its surface without any visible movement. The effect of the barometric pressure on the level of the water in the Harvey staple was very marked in the year 1884 as shown in Fig 16 (Plate V.). On this diagram, the measurements of the water-levels are inverted and reduced in the ratio of the specific gravity of mercury to that of water, so as to give parallel results. Similar variations are also recognizable on Fig. 15 (Plate V.) though not so marked, as the scales are not suitable for showing it, and there were other disturbing influences at that time.

Mr. J. B. Simpson asked what was the actual distance driven and the head of water at the time of holing. He would also like to know whether the workings were holed into exactly at the position which the plans indicated.

Mr. W. B. Wilson, Jun., replied that the length driven was about 480 feet, when the drill-hole 67 feet long encountered the feeder of water, at a pressure of 85 pounds per square inch. It was not yet known whether the workings had holed exactly at the position indicated by the plans; the distance, however, was correct, but the workings might be somewhat out of position.

Mr. Phil. Kirkup remarked that one of the greatest difficulties with which he had had to contend in boring against water was that the machine became very much clogged when the hole was damp, but with running water there was no difficulty. He also asked whether in drilling holes, which were damp, the power required was such as to necessitate the use of a ratchet.

Mr. C. C. Leach asked why the Burnside apparatus was adopted.

The President (Mr. J. G. Weeks) drew the attention of the writer to the statement that "some of the straight-on holes were continued as the face advanced, to a total length of more than 100 feet; 95 feet being the greatest length on any hole at any one time." What did this mean?

Mr. W. B. Wilson, Jun. stated that trouble had been experienced from the rods clogging in the holes, and this was especially the case in damp holes. The Burnside apparatus was used in order to have control of whatever water was found, and they were afraid of encountering more water than they could deal with. He did not think that a ratchet had ever been used, in consequence of the hole being damp. There were always two men at the handle of the boring-machine, although the services of both were not always required, unless the hole was damp, or when drilling through unusually hard material. The greatest length on any hole at one time was 95 feet; the 100 feet referred to a straight-on hole, where the hewer was continually hewing off a certain length of hole. The same hole was extended on the following night; and the total length measured from where the hole was started exceeded 100 feet in several holes. The 95 feet hole was a flank hole, and it was extended to that length because it showed signs of water.

Mr. T. E. Forster stated that he had seen the Burnside apparatus in use in Hartley colliery, and it seemed to him to be a very efficient apparatus. He thought, however, that when a machine of this kind was adopted, it should be used in every hole from the commencement to the finish of the work. He thought that considerable risk was involved in allowing the man in charge to determine when the apparatus was to be used. At a colliery in Durham, where there had been an inundation resulting in the loss of several lives, until the pick was put through the coal into the water, there was not the slightest sign of any "bleeding."

Mr. R. A. S. Redmayne stated that the Burnside apparatus had been used in the exploration which had been made against the old Hartley workings. In that case, two men per shift were employed at the machine, and a deputy was placed with them in each shift as an extra precaution. The use of the Burnside appliance only slightly enhanced the cost of boring the holes. Occasionally there had been difficulty in setting the machine, and sometimes it was difficult to withdraw, if it were tightly fixed. The longest hole at Hartley was bored to a length of 63 feet. The same men were employed continuously at the machine, although the rest of the workmen objected and claimed that they should have a turn at this bargain, but it was very necessary that they should only employ the most practical and capable men. The same front hole had been extended for 300 feet, and, except when the holes met with a "trouble," he did not think that they had once run into the top stone. Flank-holes were bored on both sides of the headings, every 6 feet, at an angle of 45 degrees and 25 degrees alternately. and for a distance of 30 feet. The front hole was kept 30 feet in advance of the face. There were no signs of water until they actually holed into the old workings with the drill: the head of water was 82½ pounds per square inch, and the workings were found within 1 feet of their position on the plan.

Mr. W. C. Blackett stated that in the accident at Kelloe, where they holed into the workings of Old Cassop colliery, the pick holed through without any previous indication of water, and the deputy (who had an extraordinary adventure, being so long underground) saw nothing whatever to alarm him before the water broke away.

Mr. J. Southern said that he had experienced great difficulty in boring with rotating machines, and owing to the rods slurring up, the men were just able to bore about 5 feet per shift. The difficulty was overcome by the use of hollow rods, which enabled them without difficulty to bore 50 feet in a shift. He had also tried the Burnside apparatus; it was very safe and reliable, and there was very little waste of water coming through the plugs. The hole was driven 80 feet, and the pressure was 180 pounds to the square inch.

Mr. Phil. Kirkup understood that the usefulness of the Burnside apparatus was really one of safety, in so far that they were enabled to control the water when it was tapped. He asked whether an angle of 30 degrees from the line of the place was the best angle at which to drill the flank-holes.

Mr. R. A. S. Redmayne said that flank-holes should be arranged so that they almost cut each other, and that no place could come in between them.

The President (Mr. J. G. Weeks) said that the safety of a colliery sometimes depended on the way in which drowned-out workings were broached, and Mr. Wilson's paper would prove valuable to students as well as to those having charge of mines. The introduction of the Burnside appliance would give confidence to the workers and secure additional safety; and where there was a heavy head of water, it should be adopted in and applied to all the bore-holes that were being made. These holes could probably have been drilled without any safety-appliance, but in certain positions, such as boring in a place to the "dip," if the workman lost his head he would probably lose the colliery as well, whereas with the Burnside apparatus he could turn a tap and attain security at once. The angle of the flank-holes and their distance apart from each other and their lengths must be left to the discretion of each manager; but he advocated the use of two straight-on holes, driven about 18 or 24 inches from each corner of an 8-feet or less place, instead of a single front hole, though each one should consider the question for himself. Care must be used so as to be as well protected on the flanks of the exploring-place as in the front of it. Cross-cuts and other ways could come in between the holes at different angles, and the bore-holes must be placed so that it would be impossible to miss such places. The smaller the width of an old working, the more likelihood there would be for the boreholes to miss it, and in making calculations as to the angle of the bore-holes they should assume that the place into which they might hole might be only 5 feet wide. He had pleasure in proposing a hearty vote of thanks to the writer of the paper.

Mr. John Daglish seconded the proposal, which was cordially adopted.