The operations of the Pumpherston Oil Company are upon a scale of considerable magnitude, for the Company’s works comprise the crude oil plant, the sulphate of ammonia plant, oil and wax refineries, etc. The Seafield and Deans works, 7 and 4 miles distant respectively, possess only crude-oil and sulphate-producing plants, the refining plants being confined to Pumpherston. The Company’s works cover 100 acres, while the shale fields extend over many thousands of acres in and around the district of Pumpherston. As has already been mentioned, the shale fields so far operated lie, in the main, in the Lothians, and, as one motors by road from Edinburgh to Glasgow, the shale country is passed through. Before the commercial development of a shale field, trial borings are sunk, now more generally by means of a diamond bore, for by its revolving action a solid core is obtained which readily shows the character and inclination of the strata passed through. When a seam of shale has been found by boring operations, and the exact position and depth of outcrop determined, it is necessary, before sinking a mine, to put down a trial shaft for the purpose of making sure as to the true gradient at which the shale is lying, and the thickness as well as the quality of the same. In the shales in the Pumpherston district there are five distinct seams, dipping from 29 degrees to 38 degrees, and the mine is driven in the middle seam, the other seams being entered by level cross-cut mines driven from one to another. Each of these seams is worked separately, the cross-cut shown in the sketch serving the purposes of communication and transit. In some cases, where the inclination of the shales is at a different angle, it is necessary to sink a vertical shaft, and this method is applied to the series known as the Mid-Calder. The usual dimensions of the inclined shaft are a width of from 10 to 12 feet, and the height is from 6 to 8 feet. If the sides of the shaft prove to be of a soft nature, as is generally the case with the shale at the crop, walls are run up and the roof is supported by larch crowns, but, where the shale is hard and the roof good, then the less costly method of timbering is adopted. The supports to the roof in many cases are fixed “centre” fashion, dividing the shaft into two unequal parts. The smaller division has generally a width of just over 3 feet, and is used for haulage ropes and water pipes, while the larger division is utilized for winding. During the progress of sinking, levels are broken away in the seam at regular distances, and driven so as to get communication with, and drive headings to form, the outer mine. These headings are driven in the same direction as the sinking mine to the levels above, until they connect with the outer mine or shaft. The outer mine is then used for winding the shale up to the surface, and the other is kept for sinking purposes, and by this means winding and sinking can go on simultaneously.