ON THE NEWCASTLE AND DURHAM COAL-FIELDS.

BY MATTHIAS DUNN, ESQ.,

Mining Engineer, Newcastle-on-Tyne.

IN submitting the following paper on this important district, it must be borne in mind that the space limited must necessarily preclude much information, with details interesting to the practical miner and collier, but which have been treated on in the works published by me* on the subject under notice, the object on the present occasion being rather to give a popular treatise than to enter into those minutiæ affecting the working of collieries or their results. I am free to confess that the paper is far from perfect in itself, but the object being to portray the most important features of this coal district, and to draw such practical conclusions as to the future which might be calculated to lead others of greater erudition than myself to investigate their truth, and draw from them some general results; if such object be achieved, I shall consider that the time devoted to the consideration of the subject will have been well employed.

Extent of explored Field.

To persons unacquainted with the locality it will be sufficient to say that the area of this coal-field is now well ascertained to consist of from 700 to 800 square miles, comprehending about 600 square miles in the county of Durham, and the remainder in the county of Northumberland.

In the former county, the present explorations are terminated to the southward by the intervention of the magnesian limestone and the new red sandstone, the thickening of which strata appears to bear down and displace the Five-quarter and Main coal-seams, which form the principal subjects in that part of the district.

To the westward, the coal-field is terminated by the outcropping of the seams approaching to the lead-mine district, of Wear Dale, Teesdale, the Derwent, and the Tyne.

In all the other parts of the coal-field it is terminated by outcropping upon the approach to the mountain limestone and the new red sandstone of Cumberland and Berwickshire. The most southerly collieries in the district are those of Castle Eden, Wingate Grange, Hartbushes Trimdon, Little Chilton, Redworth, Cockfield, and Westpits.

"View of Coal Trade, North of England," 1844; "Winning and Working Collieries," 1848.

The most westerly are those of Crook Medomsley, Mickley, Prudhoe, and Wylam, and the collieries upon the northern margin are those of Radcliffe, Broom Hill, and Acklington, in the neighbourhood of Warkworth, now likely to become important from the completion of the Warkworth Harbour and the Newcastle and Berwick Railway.

The German Ocean bounds the whole of this coal-field to the east, for, owing to the great depth at which the coal lies underneath it, there have as yet been scarcely any minings executed, although the collieries of Seaham, Monkwearmouth, Harton, &c., contemplate, in the course of time, the prosecution of their operations underneath this terra incognita, for the mines of coal, in approaching the sea-shore, for the most part flatten, would lead to the conclusion that the bottom of this important basin is not far distant from the shore.

The seams of coal of a workable thickness throughout this coal-field are numerous, but by no means so thick as in some of the coal-fields of Scotland, Staffordshire, and elsewhere, since from 6 to 7 feet constitute the thickest bed in the series, and many of them are extensively worked of the thickness of 30 to 36 inches.

Identification of Seams.

A circumstance common to all coal-fields occurs in this, and which serves to mystify the identification of the seams, viz., that in progressing from one part of the district to another, they are affected by thickening or thinning, or by the commencement or termination of bands of stone, which unite two seams into one, or separate a thick seam into two thin ones; the quality of these seams is also known to alter, from a caking quality to an open-burning white ash coal, which, together with the dislocation by dykes and the intervention of blanks in the course of exploration, served to confuse and bewilder the best-informed persons in the early stages of this trade; but in this era, when the whole field may be said to be perforated with borings and sinkings, a synopsis has been adopted, the correctness of which may be said to be admitted by the practical viewers; I will therefore subjoin it, for the purpose of drawing observation to the curious classification of qualities in the different districts :

*At Monkwearmouth Colliery, near Sunderland, at the distance of half a mile from the sea, the coal is working at the depth of 290 fathoms.

The foregoing table will show how difficult it must have been, under different local names and different characteristics, to identify the various seams in this extensive coal-field, until extensive explorations have at length reduced them to undisputed matter of fact.

Qualities of Coal.

I have already observed that the qualities of the different beds of coal are found to vary in different districts; for instance, the High Main, or Wallsend Seam, which is in the highest possible state of perfection, and 6 feet thick beneath the bed of the Tyne, in proceeding south, is split into two distinct seams of but medium quality, and a similar fate attends it at the distance of 6 miles north, where it is reduced to the height of 3 feet. The Low Main at Cramlington stands upon the highest pinnacle of reputation as an open-burning steam coal; at the river Tyne it is a good gas and smith coal, but in the Wear district it forms the subject of the Hetton and Londonderry Wallsend, or the highest-priced coal for household purposes. Many other examples may be cited, but it will be more important to notice the prevailing quality of each division of the coal-field, as it will serve to illustrate future observations as to the general bearing of this trade.

The prime household coal, then, since the exhaustion of the Tyne High Main, is the produce of the district around Houghtonle-Spring, because of its bright appearance and caking quality; but because it contains a considerable quantity of pyrites and sulphur, it is not highly estimable either for the making of gas or coke.

Coal of a similar quality to this is found in the neighbourhood of Bishop Auckland, but of a less cohesive character. Around Coxhoe, to the eastward of Durham, the Five-quarter and Main coal-seams produce coal of a similar quality, but of a secondary value; and although a hard coal, and samples in large pieces, yet it is not liked for steam purposes, on account of its admixture with pyrites and sulphur.

The Tees collieries in general possess coal of excellent quality, but deficient in value from its softness; but it has of late years become an important locality for the manufacture of coke, the whole produce in many collieries being devoted to that purpose, which is not only exported foreign, but is transmitted up the country by railways into Staffordshire, Lancashire, and much more distant counties. The coke thus made to the westward of Brancepeth is considered equal to any in the kingdom.

Of a similar nature are extensive tracts of coal around Tanfield, where, although distant from the port of shipment 20 or 25 miles, yet depend upon making their return from the manufacture of coke and the selling the coal in its raw state for the production of

gas.

coals.

The Five-quarter and Main coal are standard household

The tract of country west of Newcastle consists of the lower seams, which are there of good general quality for both house, gas, and coke, but of minor value except for smiths' purposes, the small of which brings more price than that of any other district.

The district north of the Tyne (with the exception of a few collieries working the High Main as second rate) is occupied exclusively in working the Low Main seam as a steam coal, for which purpose it stands unrivalled, and is exported in vast quantities to all parts of the world; and it does but exhibit the difficulty there is in appreciating future events in mining, when I state that until the demand for steam coal took place, this district stood so low in the scale of value, that in one property the whole minerals were purchased for £2,500, which now yield a rental of £4,500 per annum.

Mr. Richardson, an accomplished chemist of Newcastle, has analyzed several specimens of coal belonging to the district, and has obtained the following results :

:

According to the analyses of Sir H. De la Bèche and Mr. L. Playfair, in 1846, the following results were given of the relative qualities of the inflammable gases :—

To those who have perused the pages of my last publication