810 THE COLLIERY GUARDIAN. October 18, 1918. ELECTRIC SIGNALS ON A MODERN TIPPLE.* By Frank Huskinson. On a tipple that has two dumps and where coal comes from several mines, a reliable system of signals that can be heard above the noise is necessary to enable the dumpers to know when to start or stop the dumping of coal. Nowadays, when the railroads require that all Cars must be loaded to within a very small per cent, either under or over their rated capacity, it is necessary where there are several scales that these be arranged in such a manner as to give a warning signal when the car is about loaded. It is also necessary that the weigh- master be enabled, by a system of signals, to let the dumpers on top of the tipple know when to stop and when to start to dump coal, while he fui thermore must be able to signal to the lox-car loader opeiator and the car droppers, and they to him. Dry-Cells '"l/O-Vb/tsA.Q. Spring Brass. O ____a FIG.3 Strap Key for Signa) Box Tertn. C Brass Contact- Brass Roc/ -' Bell 9 L Fuses Switch Transformer iB-V. Bell-Rfngf ng Transformer F1G.5 kTerm.fC _-Rart/t/on "'Flexible Lead 'ftr^-Term. B ■ . Support Porcelain Knob^t Coil Spring Combination Bell and.Plungertype Of Push Button FIG.4 Figs. 1, 3, '4 and 5.—Details of Signal System. The tipple at the mines at Delagua, Colorado, have two dumps, each one independent of the other. The average amount of coal handled over this tipple exceeds 2,200 tons per day. There is a weigh-house for each dump on each side of the tipple to weigh the coal as it comes out of the mines. Most of the coal is loaded into box-cars. There are four railroad tracks under- neath the tipple, each with its separate scale. The slack is screened out and the balance of the coal is loaded into coal cars or box-cars. The scales for weighing the railread cars are located together in a room halfway from the bottom of the tipple to the top. One man attends to all of the weighing and billing out of all the railroad cars, and it is seldom that a car is overloaded or underloaded, due mainly to the system of electric signals. QBelltiaSTop Q)Be/iPa/Leader QlBellt/6.3 Loader . Push Button NoBTbp //.RJracks ffa/Side C\BeHKto.3 Stack Track I Fig. 2.—Wiring Diagram. [I !r? In the weigh master’s room each scale is arranged with a signal system, as shown in fig. 1. The scale beam is pivoted at A, and connection is also made here. The stop at B is normally open on the upper side until the scale beam balances. The bottom stop on B is insulated from the beam by a piece of fibre. When the scale beam balances it makes contact with B, to which another connection has been made. This closes the circuit, causing the electric bell to ring as long as the scale beam is touching B. It the eby attracts the weighmaster’s attention to the f-cale. As soon as a car is run on to the scales the weighmaster weighs it and sets the scale so that it will balance at a few hundred pounds less than the capacity of the car. He pays further attention to the scale only when the bell rings. In order to let the box-car loa.der operators know when to start or when to stop loading there is a strap key at each scale that rings a bell at the box-car loader. A strap key is also installed at each scale so that the weigh master can ring the bell at the top of the tipple to let the dumpers know when to stop or when to start dumping coal. Furthermore, the bell box at the top of the tipple is fitted with a special push button, so as to ring the bell at the box-car loader, and the box-car loader is provided with a strap key for ringing the bell on top of the tipple. Two strap keys are located at each railroad track. These keys are placed so that a fhan can signal with one of them from the ground or from the top of a box-car or coal car, to start or stop the dumping. In fig. 2 is shown the complete wiring diagram for the entire system of bells and strap keys. In fig. 3 is shown the construction of one of the strap keys. These are easily and cheaply made, and are reliable and durable, with nothing to get out of order. In fig. 4 is shown the construction of a combination bell box and special plunger type of switch, all completely enclosed in a weatherproof box, so that the weather as well as those persons that are always experimenting and putting * Goal Age. s ch things out of order cannot get to it. This switch is reliable and durable, and will not get out of order. I made up and installed the complete system as shown in the diagrams, over a year ago, and it has not given any trouble other than the dry cells having to be replaced periodically. At the present time I am figuring on taking out the dry cells and putting in a good be]i- ringing transformer. A diagram of the trans'ormer is shown in fig. 5. This can be used instead of the dry cells. The change will mem that the bells, if made for direct current, will have to be readjusted and will require more voltage from the bell-ringing transformer than they do on the dry cells. As shown in fig. 2 the scheme of wiring is interesting since it is designed to give ti e most satisfactory service with a minimum amount of wire. THE REFRACTORY MATERIALS OF SOUTH WALES.* By J. Allen Howe. The broad geological characters of the South Wales coal field are so well known that they require only the briefest notice. The carboniferous rocks lie in the form of a large simple syncline or basin, broad in the east, narrow in the west, with the older members of the systems cropping out on the north, east and smith. The refractory raw materials of South Wales, silica rocks, fireclays and dolomitic limestones are practi- cally all obtained from the carboniferous strata; up to the present time the silica rocks are the most extensively exploited. Silica Rocks. To South Wales belongs the honour of being first in the field with silica bricks. It is almost 100 years since the first company was formed to make the now celebrated “ Dinas ” bricks, which take their name from a rocky eminence, the Craig-y-dinav, situated not far from Hirwain. Silica rocks, that is, quartzites, sandstones, grits or conglomerates, capable of being employed in the manufacture of silica bricks, occur at more than one horizon in this region, but the principal source of material is the millstone grit formation. This is divisible into three portions: — Millstone Grit. Farewell rock, underlying the coal measures ... ... ... ... Oto ‘150 ft. Middle or shale group, with occa- sional quartzites ... ... ... 100 to 1.000 ft. Basal grit, conglomerate and fine- grained quartzites, grits, sandstones and thin shales ... ... ... Oto 700 ft. It is the lowest member or basal grit which alone is used for silica brick; there is abundance of material. On the north-western outcrop the three sub-divisions of the grit are most clearly defined, and the quartzite beds form well-marked ridges with a strong dip; on the north central tract the dip is not so pronounced; on the north-eastern and south-eastern crops both the upper and lower sub-divisions may pass into shales. On the north side of the basin from St. Bride’s Bay by Haverfordwest, Templeton, Kidwelly, Penwyllt, Hirwain, Blaenavon to Pontypool, for a length of nearly 140 miles, the grit outcrop is almost unbroken. Within the basal grit the beds of stone are by no means constant in character. The type most in favour is a hard, compact, fine-grained quartzite with a buff, purple-or blue fringe or colour; of these the buff or cream in some quarries and the blue in others is considered the best. This hard, fine-grained stone may pass into one of a more friable nature or into one containing pebbles of quartz, varying in size from that of a pea to that of a hen’s egg. Thus, although the outcrop of stone is so extensive, much judgment has to be exercised in the selection of quarrying sites to avoid quarrying with an exces- sive amount of waste. Moreover, the comparative inaccessibility of portions of the outcrop limits the regions of actual working to those spots that occur within reasonable distance of one of the numerous rail- ways or manufacturing centres. While the most favoured stone is the fine-grained compact variety, the pebbly and loose sandy phases are not without their uses. In some cases a hard form of the pebbly quartzite is rejected, in others it is crushed along with the finer kind for silica brick ; a certain amount of the incoherent grit may also be employed for the same purpose or for furnace sand. From west to east silica rock is quarried in the following districts: Templeton, in Pembrokeshire; Kidwelly, Llandebie, Brynamman and the B’ack Mountain, Penwyllt, Glyn Neath in the Vale of Neath, Hirwaun and Dowlais. The stone is worked in open quarries except between Upper Cwmtwrch and Pontardawe, where the quartz- ite is obtained from boulders brought down by the River Tawe. The rocks employed for silica bricks are fairly uniform in their microscopic characters; they -con- sist essentially of angular and subangular grains with silica cementation. The grains in most samples average 0-1 to 0-2 mm. diameter, but in some they are smaller, 0 03 to 0-05 mm., and in others they are slightly larger, with occasional small pebWes of quartz and chert. A small amount of mica is present in most samples, and in some a very little felspar is observable. A little iron stain may exist between the grains of quartz, and argillaceous matter in small amount is sometimes present. The following analyses (B and C), made in the laboratory of the Geological Survey, illustrate th'1 composition of representative examples of South Wales silica rocks. (A) is the analysis of a typical Sheffield ganister for comparison. Silica rocks are employed by the following firms : Abernant Dinas Silica Brick and Cement Company, * Paper read before the Refractories Section of the Ceramic Society. A. B. c. SiO 97’02 . 97'55 .. 98'14 TiO~ 0'2 i . 0'39 .. 0'33 ZrO., 0'18 .. 0'03 .. .' 0'04 A1..O3 0'34 .. O'<2 .. 0'42 Fe’2O3 0'31 .. 0'41 .. 0 44 MnO ; 0T0 .. 0'08 .. 0'03 (CONi)O nt. id. .. . . nt. fd. .. nt. fd. BaO nt fd. .. nt. fd. .. nt. fd. CaO 0'05 .. 0'02 .. Oil MgO 0 13 .. 0'03 .. 0'03 K.,0 0'09 .. 0'23 .. OTO Na2O 0 17 .. 012 .. O'T Li2O nt. fd. .. trace .. tra e H2O at 1 5 degs. Cent. 0'02 .. 0'02 .. 0'01 H.O above 105 degs. C. 0'42 .. 0'41 .. 0'19 P.O5 O'o2 .. . nt. fd. .. u'02 FeS.» 0'49 .. nt. fd. nt. fd. C 0'44 .. 0'03 .. (»'O5 CO. 0'04 .. 0'03 .. 0'06 b'0'04 .. . 100'02 ... . 100'08 Glyn Neath; N. B. Allen and Company Limited, Hir- wain ; A. Y. Dinas Silica Brick and Lime Company Limited, Mynydl-y-gang, Kidwelly; Baldwins Limited, Landore'; Black Moutain Silica Brick Company Limited, Upper Cwmtwrch; Brynamman Silica Com- pany, Brynamman; Bynea Silica Works Company, Bynea, Llanelly; Guest, Keen and Nettlefolds Limited, Dowlais; J. B. Jenkins and Company, Neath; Lime Firms Limited, Llandebie; Penwyllt Dinas Silica Brick Company Limited, Penwyllt; Templeton Dinas Silica Brick and Cement Company, Glyn Neath; H. and H. E. Smart, Kidwelly; Stephens and Company, Kidwelly; A. L. White, Morriston. As examples of typical quarry sections we may cite the two following: — Clegars Castle Quarry. (Two miles south of Narberth.) Ft. in. Quartzite, broken ... ... ... ... 4 0 Black shales ... ... ... ... ... 5 0 Quartzite, pale, current bedded ... ... 10 0 Black shales ... ... ... ... ... 9 6 Quartzite, pale, fine-grained ... ... 9 0 Black shales .............................. 0 6 Quartzite, blue ... ... ... ... 6 0 Black shales .............................. 0 6 Quartzite, blue, fine-grained ... ... 5 6 Black shales ... ... ... ... ... — Garn-tria Quarry. Ft. Quartzite, thin-bedded (not used) ........... 15 Black shales ... ... ... ... ... 3 Quartzite, thick-bedded ........................ 30 Black shales ................................. 1 Quartzite ... ... ... ... ..; ... 9 At some works the black shaies that come between the quartzite beds are calcined and ground to be added to the stone in the brick mixture; sometimes a small amount of the disintegrated rock which is found “ pocketed ” in the underlying limestone, in the con- dition of sand or grit, is added to the mix. A sandstone of triassic age, worked for various purposes on Stormy Down, near Pyle, Glamorgan, has recently been employed in silica brick making. It is rather friable and is not so free from felspar as the bulk of the^ silica rock used in South Wales. Fireclays. In South Wales and Monmouthshire fireclays are obtained solely from the coal measures; these are divisible into an upper and lower series with a middle or Pennant series, chiefly sandstones, between them. Refractory clays are worked only in the lower coal and Pennant series. Though fireclays are known in the upper coal series and the millstone grit they are not now exploited. The seams of coal in this district are usually styled “ veins ” ; they are very numerous, and the majority have received distinctive names. These names are not always easy to correlate in different parts of the coal field. The fireclays are commonly, though not invariably, associated directly with coal seams. A knowledge of the relative position of the coals is necessary, therefore, for a proper understanding of the distribution of the fireclays. Full lists of the coal seams and their correlation cannot be given here. The subject has been fully treated in the Memoirs of the Geological Survey. Although fireclays are widely distributed in South Wales, both vertically and horizontally, they are worked in comparatively few districts. The principal centres are Pontypool, Risca and Caerphilly on the eastern border; Beaufort on the north; Ystalyfera, Llanelly, etc., in the Swansea and Tawe valleys; Brynamman, Ammanford and Pontardulais in Car- marthenshire. Monmouthshire and East Glamorgan. Lower Coal Series.—The following fireclays are now raised : — The Soap coal fireclay, 8 to 9 ft. thick, at Graigddu, near Pontnewynydd, Pontypool, is employed for better class goods, together with a small amount of several other local fireclays. A clay about 45 ft. below the Soap coal at Blaendare, Pontypool, is 5 ft. thick. It lies about half-way between the Soap Vein and the New or Elled Vein. Three clays respectively 34, 27 and 21 ft. above the Elled Vein, at Ebbw Valq. The following section shows their position: — Ft. in. "No. 2 fireclay ” (working) .............. 2 6 Black shale (working) .................... 3 0 Shale ... ... ... ... ... ... 1 6 Coal '.................................... 0 8 “No 1. fireclay ” (working)............' 2 0 Rock ... ...... -... • ............. 0 8 Rashings ... ... ... ... ... 0 4 “ Elled fireclay ” (working) ... ... 5 0 Thin sandstone ........................) 9, n Shales .................... ...........)Zi U Elled coal .......... ................. — The Red Vein fireclay and Big Vein fireclay at Wernddu, near Caerphilly, The quarry shows : —