THE COLLIERY GUARDIAN AND JOURNAL OF THE COAL AND IRON TRADES. Vol. CVII. FRIDAY. FEBRUARY 27, 1914,. No. 2774. Geology of the South Staffordshire Coalfield. IMPORTANT DISCUSSION AT BIRMINGHAM. A meeting of the South Staffordshire and Warwick- shire Institute of Mining Engineers was held at the University, Birmingham, on February 16, 1914, Dr. J. Cadman (president) in the chair, when Mr. F. B. Clark read a paper entitled “ A Description of the Headings Driven from the Aldridge Collieries to Prove the Mines over the Main Eastern Boundary Fault.” Mr. Clark gave a short description of the section at the Aldridge Collieries. The shafts first passed through 136 yards of brickclays, and after penetrating the THE EASTERN BOUNDARY FAULT. troubled ground, would strike the Deep coal lying at a depth of 900 yards below the surface. Two parallel headings were accordingly driven 30 yards apart, dipping 1 in 4. The headings left the Deep coal at a depth of 450 yards, and entered measures which were between the Upper coals and the brick clays. The ground was very broken, and contained numerous slip planes and small faults, but the general dip of the strata was in the direction of the heading and at about the same rate. At 265 yards No. 2 heading struck mottled red and grey marls, but they disappeared at 290 yards. These marls of dip increased, and it disappeared under the floor of the headings. Then followed an extremely broken piece of ground up to 990 yards, but the general dip of these broken strata was in the direction of the heading, although much steeper. At 990 yards, however, the strata became more regular, but still remained very steep. These continued more regularly from 990 to 1,117 yards, and the dip gradually became less. The upper measures were again passed through, but this time in the reverse order (as the strata gained on the heading). At 1,120 yards an upthrow was met which brought up the Four-feet coal into the roof; and at about 1,145 yards another upthrow fault was pierced, which brought up the Five-feet coal into the roof. At 1,187 yards a downthrow fault was struck, and the measures dipped steeply as soon as the fault was passed through. These measures were evidently the passage beds between the brick clays and the productive measures. At 1,230 yards the real brick clays were entered, and the heading continued in them up to 1,310 yards, when it was abandoned; the marls at that point were still dipping, although the ground was so lacking P/T SHAFT IOO Y°-s 2 00 •• 300 •• 4-00” 500” 600 •• 700” 800 ” 900” \ ——• Seven -/ A/’ze-/ 'eet Coal set Cos/ ~eet Coal ch Coal ESI WWMS3 Q \ V Deep and Sha/ low Cos! Vx yard Goa/ z \ “^z? z> . c > \ x\ ■ Feet Cqj! 0 0^5 4?- Q \ —Brooch r_, TvVe Feet F TZTcKZ - teo9 q /■Four-Feet (Five-Feet K A - As/ V*' 1 / i r a sped // //adl 01 Jv II k Clap / \ lOOYR5 200 300 400 500 600 700 800 900 1,000 1. JOO 1,200 1,300 Section of Shaft and Heading at the Aldridge Collieries. passage beds entered the true productive coal measures. The first coals met with are spoken of as the “ Upper coals,” and are named the Seven-feet, the Four-feet, the Five-feet, and the Brooch seams. The coals below are generally called the “ Lower coals,” and are named the Yard, the Shallow, and the Deep seams. The Lower coals are the most profitable; the margin of profit in working the Upper coals is very small—indeed, some of them will not pay to work. Having regard to these conditions, the colliery com- pany considered that, as the mining difficulties would be considerably enhanced if the mines on the down- throw side of the Eastern Boundary fault were worked, probably only the Lower coals could be worked advan- tageously. The best geological opinion that could then be obtained was taken, and it was considered that the headings, after passing through some distance of were not seen in No. 1 heading, and must have been those forming the passage beds between the brick clays and the productive coal measures. At about 515 yards an upthrow fault brought in the Seven-feet coal, but almost immediately another upthrow fault of no great throw brought up the Four-feet coal, and from this point the ground became more regular, dipping about 1 in 8 in the same direction as the roads. The headings thus gained on the ground, and the Five-feet and Brooch coals (the lowest seams in the Upper coals) were passed through. The ground continued to be fairly regular, until at 837 yards a very clearly-defined upthrow fault was encountered. At 860 yards the Yard coal was struck, which proved that the fault passed through at 837 yards must have had a throw of approximately 90 yards. This. Yard coal, which was first struck in the floor, formed the roof of the heading from 880 to 940 yards, when its rate in stratification that it was very difficult to estimate the exact amount. Espley rock was struck at 1,276 yards, confirming the opinion that they were the brick clays. The headings were examined by Dr. T. C. Cantrill and Dr. Walcot Gibson, of the Geological Survey, and also by Mr. J. T. Stobbs, all of whom were of the opinion that they were the brick clays. At various places small quantities of very salt water were struck, and although it never at any time exceeded 6,000 gallons per day, it was sufficient to act upon the numerous places where there was fireclay, causing the floor to heave and the sides to give way. The lateral pressure in places was much more than is usual in the district generally, and in many places the ground was very contorted. It will be gathered from this that the headings were extremely difficult to maintain, and this was particularly so in the brick clays; even when these clays were dry, they seemed to