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The coal from the four seams at present working is bituminous coal of good quality-the Five Quarter and Low Main seams produce household coal, the Hutton and Harvey seams, gas coal.

Fire-damp is very rarely seen in the seams above the Harvey. seam is moderately gaseous.

The Harvey

The depth not being great, and the overlying limestone containing much water, the strata, in which mining operations are carried on, are not on the whole dry. The Harvey, the lowest seam, is dry. The main haulage roads traversed by the intake air currents were the driest parts of the mine, and these roads were occasionally watered on the floor.

The coal worked from Wingate Grange Colliery, like all Durham coal, produces dust when in a dry state. Of the four seams worked the coal from the Harvey seam was of the softest nature, and could be described as the most likely to produce dust, and it lay at the greatest depth where the hygrometrical conditions were most favourable for dry coal.

The downcast shaft, the Lady pit, 14 feet in diameter, is sunk to the Harvey seam. This shaft is traversed by two pairs of cages running in wooden guides; one pair runs between the surface and the Harvey seam, and the other pair between the surface and the Hutton seam.

The upcast shaft, the Lord pit, also 14 feet in diameter, is situated 44 yards to the south of the downcast shaft; it is also sunk to the Harvey seam and continued four fathoms further, but is only fitted with wire rope guides to the Low Main seam; immediately below this seam were three scaffolds; the cages rested on the first, the second was used in connection with the wire rope guides, and the third was a protecting scaffold; a little air ascended past these scaffolds.

Both shafts are cased with cast-iron tubbing through the limestone.

In addition to these shafts there are some subsidiary shafts or staples between the various seams, only three of which it is necessary to describe. Twenty-five yards from the downcast shaft is a staple 10 feet in diameter between the Main Coal and Harvey seams, which acts as upcast for the Harvey and Hutton seams as far as the Main Coal seam. At the top of this staple in the Main Coal seam is a winding engine supplied with steam. This staple is capable of being used in conjunction with a kibble or bucket, not running in guides, for the ascent or descent of persons between any two of the four seams.

A staple, in close proximity to the staple just described, extends between the Low Main and Harvey seams, and is provided with a steam winch at the Low Main seam to raise or lower persons by a kibble between the seams. This staple is not used for ventilating purposes, and is called the "dumb staple."

A staple between the Main Coal and Low Main seams, situated 110 yards north of the downcast shaft, and by the side of the main haulage road, 10 feet diameter, is used for lowering coal from the Five Quarter and Main Coal seams to the Low Main seam, whence it is taken to the upcast shaft and raised to the surface. At the time of the explosion the Main Coal seam, as already stated, was not being worked, and only coal from the Five Quarter seam is dropped down the staple; the coal is run down a self-acting incline in a stone drift between the Five Quarter and Main Coal seams, and then led by horses along a road in the Main Coal seam for a distance of 380 yards to the top of the staple.

The staple is fitted with a drum and two cages, each holding one tub, and is worked in the ordinary manner-the cage and full tub in descending raises the other cage and empty tub.

Two ranges of steam pipes, supplying underground hauling engines in the Low Main and Harvey seams respectively, as well as a small pumping engine in the Harvey seam, enter the upcast shaft at the surface.

The range for the Low Main seam leaves the upcast shaft at the Main Coal

Low Main seam; the range for the Harvey seam also leaves the upcast shaft at the Main Coal seam and is then carried down the downcast shaft.

A range of pipes extends down the downcast shaft from the surface to the Hutton seam, supplying a pumping engine there with steam; a branch pipe from this range supplies a pumping engine in the Main Coal seam, which provides the village with water, and also the winding engine at the top of the Harvey seam staple; another pipe leaves this range at the Low Main seam, supplying the steam winch at the top of the dumb staple.

Considerable feeders of water, amounting in the aggregate to 650 gallons per minute, met with principally in the seams above the Hutton seam, but running to that seam by staples, are forced to the surface by the pumping engine in the Hutton seam, which is the main pumping engine of the colliery.

A vertical section showing the two shafts and the three staples described is given on Plate I.

The seams are worked both on the longwall and bord and pillar systems.

In the Five Quarter seam there are extensive workings. In the Main Coal seam a large area has been worked over, but operations in this seam have been suspended for two years.

The Low Main seam is, as the plan on Plate II. shows, worked over a large area.

The Hutton seam has not been worked as extensively as the other seams, and its working was only resumed four years ago after standing for forty years.

The Harvey seam has been worked over a large area and now produces the greatest output

Hauling engines are placed underground near the shafts in the Low Main and Harvey seams. An engine-room for a hauling engine is being prepared in the Hutton seam. The coal is led from the working faces in the various seams by ponies, then by horses or self-acting inclines, and lastly by engine power actuating ropes on the main and tail rope system. The engine haulage roads are in all cases on the intake air roads.

One hundred and seventy horses and ponies were in the mine on the day of the explosion.

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The tubs used are of four kinds. Iron tubs carrying 10 and 8 cwts. respectively are used in the Harvey and Hutton seams. Wooden tubs carrying 8 cwts. and 10 cwts. respectively, are used in the Low Main and Five Quarter seams. All these tubs were well constructed.

The return air roads are only used as such and not as travelling roads or main haulage roads.

The miners in going to and returning from their work used both shafts and the main haulage roads. During the intervals between the coal winding shifts only a winding engineman at the Harvey seam engine was on duty.

The colliery is ventilated by an exhausting Waddle fan 25 feet in diameter running ordinarily at 85 revolutions per minute, placed on the surface 25 yards from the upcast shaft, with which it is connected by an arched tunnel.

During the evenings of ordinary working days, while the pit was not occupied by the hewers, and at the ends of the week, the speed of the fan is reduced from 85 to 82 or 83 revolutions, and the water-gauge from 3 inches to 2.80 inches; this slightly reduces the quantity of air circulating in the mine.

A Guibal fan 36 feet in diameter and 12 feet wide, producing about 102,000 cubic feet per minute under a water-gauge of 1.80 inches, had satisfactorily ventilated the colliery up to three years ago; at that time the colliery was partially flooded by surface water, the foundations of the fan rendered insecure, and it was replaced by the present fan.

The total quantity of air extracted by the Waddle fan amounted to 193,478 cubic feet per minute when measured in the fan drift on the 27th September last. On the same day the quantity measured in the various splits in all the seams amounted to 155,138 cubic feet per minute under a watergauge of 3 inches.

In order that the top of the upcast should remain closed while either cage is at the surface, a suitable wooden casing with sliding doors is provided; a similar arrangement is in use at the Low Main seam, in order to secure the advantages of fresh air in the vicinity of the shaft.

The currents of air ventilating the mine leave the downcast shaft at the various seams in which they circulate, with the exception of the current ventilating the Five Quarter seam, which leaves the shaft at the Main Coal seam, passes along the road in that seam already mentioned, and then up the stone drift to the Five Quarter seam.

The return air current from the Harvey seam ascends the staple extending between that seam and the Main Coal seam, and on reaching the Main Coal seam passes to the upcast shaft. Part of the return air from the Hutton seam enters the upcast shaft direct, and the remainder ascends the staple between the Main Coal and Harvey seams. The Low Main seam return air also passes up this staple.

The discontinued workings in the Main Coal seam are ventilated by scales of air from the intake air passing to the Five Quarter seam.

The return air from the Five Quarter seam enters the upcast shaft direct.

The stoppings, doors, air crossings and regulators, used for directing and controlling the air currents, are of the usual type, but all the crossings in the Low Main seam except two, one of which is a brick arch and the other a point of crossing where the return air-way is in strata above the intake air way, are of the flat-topped wood type.

The air ventilating the Low Main seam leaves the downcast shaft by three short roads leading on to the main haulage road, one small current passes to the upcast shaft and provides the onsetters there with fresh air.

The main current, amounting to 36,348 cubic feet per minute, as measured on the 27th September last, passes in-bye and past the drop staple. This staple is in communication with the intake in the Main Coal seam above and with the intake in the Low Main seam below, and the air in it sometimes moved up and sometimes down; it was described by the under-manager as being "on

the balance."

Arrived at the Stable way junction the current splits, 10,140 cubic feet per minute passes into the Stable way, while the remainder, 26,208 cubic feet per minute, continues north. There are doors in the haulage road beyond the landing in the 1st East way, and only a scale of air passes up this road.

The current continues north to the curve, and then passes to the faces of the 2nd East way, and on its way back to the upcast shaft, ventilates the working places of the 1st East way.

The course of the air currents and the necessary doors, stoppings, air crossings and regulators are shown on the plan, and need not be further described.

At the working faces, in all the seams, only safety lamps of the Marsaut or Donald type are used by the workmen, locked by means of a lead The plug. The officials use lamps of a similar type or tin-can Davy's. lamps used by the officials are secured by a screw lock. Near the shafts in the intake air ways incandescent electric lights are used during ordinary working hours supplied by a current brought from the surface by a cable in the downcast shaft. A limited number of naked lights were used, in the Low Main seam only, by wagon-waymen and other persons working on the

main haulage roads, in the intake air ways up to the caution boards, which are shown on the plan. At the caution boards, a lighted tin-can Davy lamp, with red glass, is hung during the time the pit is occupied by the hewers, &c.

Explosives are used both in coal and stone in all the seams. In the Five Quarter, Hutton, and Harvey seams, Faversham powder is used for blasting the coal and geloxite for blasting stone. Both these are Permitted Explosives and are fired by battery. In the Low Main seam compressed gunpowder, fired by the deputies by the application to a squib, of a wire, heated at the flame of a safety lamp, is the explosive used by the hewers, while geloxite with fuse and detonator fired in a similar way is used in stone. Explosives were rarely used in the Low Main seam at any point except the working faces, which are not dusty and are free from fire-damp, in which situation it was held the Explosives in Coal Mines Order did not apply, and the geloxite, although a Permitted Explosive, was only used as an extra precaution, and because it was found not unsuitable for blasting in stone.

Geloxite is described as follows in the Explosives in Coal Mines Order of the 10th December, 1903 :

Gexolite, consisting of the following mixture:

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the wood-meal to contain not more than 15 per cent. and not less than 5 per cent. by weight of water.

Provided :

(1) That the explosive shall be used only when contained in a non-waterproofed wrapper of parchment paper;

(2) That the explosive shall be used only with a detonator or electric detonator of not less strength than that known as No. 6 (i.e., the detonator or electric detonator to be used shall possess an effective detonative strength as great as, or greater than, that of one containing 15 grains of a composition consisting in every 100 parts by weight of 80 parts of fulminate of mercury and 20 parts of chlorate of potassium);

(3) That the explosive has been made at the works of the Cotton Powder Company, Limited, at Uplees Marshes, near Faversham, in the county of Kent, or at their works near Melling, in the county of Lancashire;

(4) That the explosive is in all respects similar to one or other of the samples submitted to test on the 26th day of May, 1902, or on the 15th day of September, 1903;

(5) That in addition to the marking on the outer package required by an Order of the Secretary of State, made under the Explosives Act, 1875, and in force for the time being, such outer package shall bear the words "As defined in the List of Permitted Explosives:" and, further, that each inner package shall be clearly marked with the words "Permitted Explosive, to be used only with not less than No. 6 detonator," and also with the name of the explosive, the name of the manufacturer, the date and place of manufacture, and the nature and proportion of the ingredients; and

(6) That the explosive, if in a frozen condition, shall be thoroughly thawed in a safe and suitable manner before use.

No person was allowed to use explosives in the mine, or carry detonators, without an authorisation, partly printed and partly in writing, signed by the under-manager.

There is a screening plant on the surface for both pits; these plants, shown on Plate III., are in separate buildings and are not connected except by a gangway.

The shifts of workmen are arranged as follows:

A shift of hewers, known as the fore shift, descends the shaft at 4 a.m. and works up to 10.30 a.m., and the places they occupied are then filled by a similar number of hewers in the back shift, who descend the shaft at 9.30 a.m. and work up to 3.30 p.m.

A haulage shift of men and lads descends the shaft at 6 a.m. and leads the coal produced by both shifts of hewers, ceasing work at the same time as the back shift hewers.

A repairing and stonework shift occupies the mine at night. On ordinary nights, the shift in the Five Quarter seam extends from 8 p.m. to 4 a.m., in the Low Main seam from 9 p.m. to 5 a.m., and in the Hutton and Harvey seams. from 10 p.m. to 6 a.m., but on Sunday nights this shift descends together at 10 p.m., being preceded by a shift of examiners.

The general control of the whole mine is exercised by Mr. W. Armstrong, who acts both as agent and manager. Mr. Armstrong is a mining engineer of considerable eminence, and was President of the North of England Institute of Mining Engineers in the year 1898. He is also the senior partner in the wellknown mining engineering firm of Messrs. Wm. Armstrong & Sons.

The under-manager, Mr. Robert Owen, holds a second-class certificate of competency, and has passed through all the grades of mining work, and has been at Wingate Grange Colliery in various capacities for 40 years.

There is a sufficient staff of under officials, consisting of 4 overmen, 3 backoverman, 1 master wasteman, 3 master-shifters, 42 deputies, and 15 examiners in the night shift. Mr. T. Robson, a competent mechanical engineer, has charge, under the manager, of all the machinery and boilers, both above and below ground.

There was nothing unusual in the atmospheric conditions on the day of the explosion.

The barograph taken at the Colliery for that day and the two preceding days is given below:

FRIDAY OCT. 12" SATURDAY OCT 13TH SUNDAY OCT 14TH MONDAY. M'2 4 6 8 10 XII 2 4 6 8 10 M2 2 4 6 8 10 X 11 2 4 6 8 10 MT2 4 6 8 10 XII 2 4 6 8 10 MT 2 4 6 8 10

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