Thinking that a Paper on this subject would be interesting and acceptable to the Institute, I have drawn together the most prominent features of this extensive undertaking and tabulated some of the more detailed particulars in such a way as may be easy of reference. The details, although not presenting any novelty to the senior members of the Institute, may, I trust, be found serviceable to the student in the art of Coal Mining.

The preliminary process of sinking, or in its more enlarged signification — winning a colliery, is one which is of the most vital importance to the future well-being of the undertaking either as an investment or speculation, whether we consider the amount of capital to be expended before the coal is reached, or again, the position or site of the plant for the future effective and economical working of the mine when completed.

In new or unexplored districts the risk of error in position, or powers of machinery required to overcome the ordinary difficulties met with in sinking is necessarily greater; but even where the district is better known, improper or unfortunate positions have frequently been selected, and the future well-being of the colliery seriously affected.

The general rise and dip of the seams of coal in the county of Durham and Northumberland are now well known, as well as the principal dislocations of the stratification by Dykes, &c.; but a prudent miner will think it advisable before commencing operations for a new colliery to prove the ground, by boring or otherwise, before he embarks the capital of his employer.

The magnesian limestone, overlying the eastern part of the county of Durham, and increasing in thickness in its eastward course by the natural dip of the coal measures in that direction, has attained its greatest known thickness at Castle Eden, the bottom of the bed there found being 105 fathoms from the surface. Depths from the surface to bottom of limestone proved at the following places :—

Murton Winnings	76	fathoms.
Seaton Park	67	,,
South Hetton	64	,,
Shotton Colliery	63	,,
Wingate Grange	58	,,
Seaham Harbour (not through)	56	,,
Monkwearmouth	52	,,
Haswell	50	,,

The upper portion of the limestone is soft and often overlaid by a marl of a light cream colour, generally free from moisture and easily worked. As you proceed downwards the limestone becomes more compact and hard, the lower portion being difficult to work on account of the gunpowder finding vent in the cavities with which this rock abounds.

Underneath this limestone generally lies a bed of sand, varying in thickness and hardness, accompanied by feeders of water also varying very materially in quantity.

Several shafts have been put through this treacherous stratum, in various parts of the county, and its structure, in some places, found very soft and dry, in others interspersed with hard chert riders, having a honeycombed appearance, the cells being divided by cherts, in some cases these flinty parts are almost stratified. Near to the Ferryhill Station, on the North Eastern Railway, a good section of it may be seen capped with the magnesian limestone, also under the Castle and Lighthouse at Tynemouth.

After these preliminary observations, I shall proceed with the more immediate subject of this paper.

Murton Winning is situated to the north-east, or nearly full dip of South Hetton Colliery, and was projected to win the extensive range of dip coal intervening between that colliery and the German Ocean. It is within two miles of Seaham Harbour, and a short distance from the village of Dalton-le-Dale, which circumstance for some time gave it the name of the "Dalton Winning."

After several borings had been put down in various directions, through the limestone rock, to prove the thickness of the sand, the site was selected and the ground broken for the first shaft on the 19th February, and for the second shaft on the 10th April, 1838.

The winning was first arranged to consist of two shafts, of fourteen feet clear diameter each, and to be divided so as to form ultimately three coal drawing pits, and one engine or water drawing pit.

The engine power consisted of three 120-horse power winding machines, and one pumping engine of 250-horse power, together with other small engines in lieu of jacks and gins.

It being the intention of the parties to use some, if not all, the machines as auxiliary pumping engines during the progress of sinking, these machines were so placed that in the event of an accident occurring to any of them, the ropes or other appliances could be made available for a time to the others until any necessary repairs were effected.

To the main engine were attached six sets of 19-inch pumps, in three lifts of twin sets, viz.: the two top sets in a staple worked by the back bram, the two middle sets worked by the V bob in the pit, and the two bottom sets hung on sevenfold blocks in the bottom of the sinking shaft.

To each of the machines were attached three sets of 16-inch pumps, viz. the top set in the counterbalance staple under the end of the crank shaft, the middle and bottom sets being worked by a horizontal spear and quadrants placed over the shaft.

The sinking of the two shafts proceeded, without obstruction, to the depth of thirty-five fathoms each, where the feeders of water, gradually met with, accumulated to fifty gallons per minute in one pit, and seventy-gallons per minute in the other, the water being, hitherto, drawn out by iron water tubs, containing 60 and 140 gallons each. The sinking was then suspended, and the first metal wedging crib (14 inches by 6 inches) laid, and two fathoms of light metal tubbing put on to outset the main body of the feeder, and the shaft walled up and secured to bank, and further sinking suspended until the machinery was ready. The counterbalance staples for the machines were then sunk, and galleries driven between them and the two pits for conveying the water between the middle and top sets of pumps.

The machinery and pumps being in readiness, the sinking was resumed on the 19th November and continued down to the depth of 70 fathoms, when a double metal wedging crib was laid to rest the two standing sets upon, and the shafts tubbed off and closed under the first wedging crib. The sinking was then resumed and continued six fathoms further, where another wedging crib was laid and the shafts rendered dry to this point, being the last tubbing got in before arriving at the sand. After leaving a sufficient strength of limestone as a support to this last named crib, the shafts were enlarged or belled out before arriving at the sand to enable us the better to contend with the anticipated difficulties, and also to maintain in the end the full diameter of the shafts.

This latter resumption of sinking had not been proceeded with far before the bottom of the pit blew up like a blast, and a deluge of water, sand, &c., was thrown up which speedily drove all hands out of the bottom. The lower sets of pumps being then short and hung upon strong 7-inch ground ropes attached to 7-fold blocks and crabs, were hove up out of the bottom, and the water allowed to settle. Upon plumbing the pit it was found that 9 feet in depth of sand over the whole bottom of the shaft had been sent up through the fissure. The two machines went 18 strokes per minute with a 4 feet stroke = 684 gallons per minute.

The east pit was sunk upon one of the boreholes which followed the course of that shaft pretty regularly. The borehole was kept secured in advance by a long plug, when, however, the sinking was within twelve fathoms above the bed of sand, the plug burst out and a considerable quantity of sand was thrown up. This was the first intimation we had of the loose nature of this formidable opponent. The feeder through this borehole kept the 16-inch set going 12 strokes per minute with a 4½ feet stroke. The pressure of water in the other pit being 18 fathoms. Both pits being now opened to the sand, the gross amount of the feeders of water proceeding from it was found to be more than a match for the pumping power applied, which, at this time, was confined to the 16-inch sets attached to the machines, the East Main Engine being yet in the hands of the manufacturer.

During the progress of sinking thus far, the system of intercepting each considerable feeder of water as it was met with, was steadily practised and every good foundation for a wedging crib promptly, and with great success, turned to account. By this means the shafts were kept remarkably dry until the period when the sand feeder forcibly broke away through the bottom.* The metal tubbing being carefully backed up with marl, which, on being saturated with water, became like cement and formed an impervious backing.

It may probably be interesting here to note the successive feeders dammed back by the different batches of metal tubbing.

The metal tubbing used in these shafts was in segments of 2 feet and 18 inches in height, having ten segments to the course or ring. The thickness of metal varied as the pressure increased, being ¾-inch at the top, 1-inch in the middle, and 1¼-inch at the lower part of the limestone and sand. In front of the sand tubbing, where the pressure was greatest, metal rings 9 inches in depth were placed for additional security in front of the joints and set firmly against them with iron keys.

The sheathing used was made out of clean memel deals, planed to a uniform thickness of an inch, and wedged until no moisture was visible at the joints, which were then adzed off. Previously to being put in the tubbing was all carefully examined, the front surface scraped and painted with a strong bodied anti-corrosive paint which remained afterwards like an enamel upon its surface.

* I understand that a different plan is now being tried at the Ryhope Winning, viz: pumping all the feeders as they are encountered in the shafts — this will probably increase the difficulties where they approach the sand.