Mabch 20, 1913. _________________________________________________________________________________________ — PROGRESS. - _____________ Mine LocomG tires in the Dortmund District. An interesting account of the use of locomotives in collieries in the Dortmund district has appeared in the Zeitschrift fur das Berg, Hutten- und Salinenwesen. This development has been greatly fostered by the rise in the cost of production dating from 1890, the increased wages of hauliers having entailed considerable changes in method and organisation. In the period 1889 to 1898 no less than 71 endless rope haulages were installed, but the tortuous roadways in the Westphalian collieries have militated against the employment of this system, especially in the subsidiary haulage roads. Consequently there has been an increasing application of benzine or benzol locomotives—electrical locomotives on the trolley or accumulator systems, and more lately compressed air and single-phase electric locomotives. The course of this development is indicated in the accompanying chart (fig. 1). Fig. 1.—Chart showing the Employment of Mine Locomotives in the Dortmund District. 1904 1905 1906 1908 1909 I90D __BENZINE & BENZOL LOCOMOTIVES LOW-TENSION CONTINUOUS CURRENT DO. HIGH-TENSION SINGLEPHASE DO. ♦ BATTERY DO. COMPRESSED-AIR DO. 20 10 300 90 80 70 60 50 40 30 20 10 g200 90 .80 70 60 50 40 30 20 10 100 90 80 70 60. 50. 40. 30. 20 10 ! 1907 YEARS One of the consequences has been a change in track construction. Formerly rails were used weighing from 6’8 to 12 kilogrammes per metre, with a height of from 65 to 80 millimetres. The weight has now risen to from 14 to 18 kilogrammes and the minimum height to 80 millimetres, approaching in some cases 100 milli- metres. Another result has been a consistent enlarge- ment of the section of roads, the dimensions of the double-track roadways generally adopted being as follows:—Width at ground level. 3 5 to 3’7 metres; width at roof, 2 3 to 2 7 metres; height, 21 to 2 2 metres. The gradient for locomotive haulage may be put at 1 in 400 to 500, but inclinations of 1 in 150, or even 130, are encountered. Taking first benzine and benzol locomotives, the great preponderance of those used in the Dortmund district have been constructed by the firms of Deutz and Oberursel. Their general construction is as follows: A 4-cylinder motor is mounted on a chassis of forged iron, the weight on the axles being taken by springs. In the Deutz locomotives the transmission is effected by sprocket wheels and chains, with friction coupling; but the Oberursel locomotives are driven direct by gearing. The usual capacity is 12-horse power, but recently locomotives of ‘16-horse power have been installed. The general dimensions of these two types are as under:— 12-h.p. 16-h.p. locos. locos. Length ..................(metres) 3 5 ... 3’8 Width ..................( „ ) 0’9 ... 10 Height without hood......( „ ) 1’5 ... 1*6 Weight ....................(tons) 5 0 ... 6 0 Maximum speed per second— ----v----* First speed ..........(metres) 1’7 Second speed ........( „ ) 1’7 and 2’5 The motors are protected against firedamp. The direct-current trolley locomotives employed are uniform in type, being governed generally by tramway controllers, and comprising two motors. For normal speeds the motors are arranged in parallel. The usual voltage is 220. At each point in the roadway it is possible to transmit signals to the haulage station. The single-phase locomotives take current on one phase of a three-phase circuit of from 1,000 to 5,000 volts. At distances of 400 to 500 metres transformers THE COLLIERY GUARDIAN. 607 are placed, the secondary poles being connected on the one hand to the ventilation pipes, and on the other to the rails. The high-tension current is transformed to 250 volts. Mechanically the single-phase locomotive does not differ from the continuous-current locomotive. The battery locomotives are provided with portable Bohm accumulators, each locomotive carrying a spare battery. Otherwise they are similar to those already referred to. The dimensions are as follow :— Dimensions of loco, and battery Horse- Capacity of in millimetres. power. battery. t----------------------K-------------- Length. Width. Height. 8 [80 elements 7 2,740 930 x 500 (30 ampere-hours J * ’ 16 f elements j 3 999 __ 959 1 500 (74 ampere-hours J ’ * 20 £ 74 1 3-990 - 1,060 - 1,500 (74 ampere-nours) ’ ’ Charging is carried out at a station placed in the road- way or near the source of the current. A compressed-air installation comprises compressors, delivery mains and locomotives. The compressors furnish air compressed to 100 atmospheres. The mains consist of weldless steel tubes 35 mm. internal diameter; at the pit bottom five reservoirs, each 500 mm. in diameter by 5 m. long, serve to regulate the pressure, but in more recent installations the diameter of the mains has been increased to 75 mm. and the reservoirs obviated. The accompanying illustration (fig. 2) shows, with sphere in low and tortuous roads. On the other hand, in roads of ampler section, where the haulage is of an intensive character, it is preferable to adopt the trolley or compressed air systems. ________________________ THE GEOLOGICAL SOCIETY OF LONDON. Dr. Strahan’s Address. At the annual general meeting of the Geological Society of London, Dr. Aubrey Strahan, F.R.S., delivered his presidential address, as the main object of which he discussed the form of that part of the palaeozoic platform which underlies the secondary rocks of the south-east of England. He said upwards of 40 borings had been carried down to it, and have provided sufficient evidence for the construction of a contoured map of parts of it. Two regions are still unknown, namely, the southern counties and a tract extending north-westwards from the estuary of the Thames ; but, between the two, counter lines at 500,1,000 and 1,500 feet below sea level can be drawn for considerable distances. The form of the platform thus illustrated shows no connection with its geological structure, so far as that is known, and may be attributed to planation, for the most part by marine action, and to warping by the post - oligocene movements which produced the dominant structure of the south-east of England. ------------0.10 ------------ MM /fOO -HMM- +0OU- Fig. 2.—Schwartzkopff Compressed-air Locomotive. Dimensions : —Diameter of cylinder, 125 mm.; piston stroke, 250 mm.; diameter of wheel, 500 mm.; pressure in main reservoir, 50 atm.; pressure in working reservoir, 10 atm.; capacity of main reservoir, 1,664 litres; Weight of locomotive (empty), 5,400 kg.; ditto (in operation), 5,650 kg.; width of track, 520 mm. principal dimensions, one of the locomotives made by the firm of Schwartzkopff. The quantity of air necessary for feeding the cylinders is furnished by a reservoir of 1J cubic metres. A reduction valve reduces the pressure below 10 kilogs. A reservoir of 100 litres receives the expanded air before it reaches the cylinders. The principal dimensions and capacities of these locomotives are as follow:— Diameter of cylinders, 125 mm.; capacity of main reservoir, 1,664 litres; stroke of pistons, 250 mm.; weight (empty), 5,400 kilogs.; weight (in use), 5,650 kilogs.; diameter of wheels, 500 mm.; pressure in main reservoir, 50 atmospheres ; pressure in secondary reser- voir, 10 atmospheres ; width of track, 520 mm. A typical locomotive, with a speed of 9 to 12 kilo- grammes per hour, will do the following work:— Admission Extrac- Power required for the following of air in tion cylinders, effort. >---------- Per cent. Kilogs. 75 ... 780 ... — 60 ... 547 ... 18-4 42 ... 390 ... 12’2 33 ... 312 ... 10’5 25 ... 235 ... 7’8 Trials made in various speeds at starting: 2’77 m. 3’05 m. 3 93 m. H.p. H p. H.p. 20’4 *” 22 5 7. 24 5 ... 14’4 ... 15’8 ... 173 ... 116 ... 127 ... 140 ... 8’7 ... 9 6 ... 10 5 mines have resulted in the following costs per kilometric ton:— A. Benzine or benzol locomotives (including Pf. depreciation)......................... 13 B. Direct current trolley locomotives (in- cluding depreciation) ................. 11*3 C. Single-phase trolley locomotives (including depreciation) ......................................... 8’4 D. Battery locomotives (including deprecia- tion) ................................ 137 E. Compressed-air locomotives............ 11 The conclusions arrived at are that the benzine loco- motives present dangers in the direction of fire and the ignition pf firedamp, and the cost of upkeep of their parts is excessive. The trolley locomotives present a great elasticity from the point of view of realisable work, and the cost of running is lower than with any other system, but there is the danger of fires through short- circuiting. The battery locomotives are very safe from the point of view of fires and explosions, but the upkeep of the batteries is a delicate and troublesome matter. The compressed - air locomotives are very strongly constructed, easily managed, and, by reason of the simplicity of their upkeep, no more costly than the other systems. Benzine and battery locomotives find their principal To illustrate the effect of these movements a second map had been constructed, showing contour lines in the base of the gault at intervals of 500 ft., extending from 500 ft. above the sea to 2,500 ft. below it. The result was to give a comprehensive view of the warping undergone by the upper cretaceous and tertiary rocks, and of the magnitude of the movements. The height above sea- level to which the base of the gault has been raised, and the depth below sea-level to which it has been depressed can be estimated approximately at every point from the contouring. It thus became possible to see what corrections are necessary to restore the base of the gault to horizontality, and thus to eliminate the effects of the post-oligocene movements. By making this correction in the first map, the palaeozoic platform was restored to the form that it possessed before those movements came into operation. A third map, thus constructed, showed that considerable changes were effected. A tract of high elevation clearly defines itself under London and near Harwich. On the northern and southern sides the contour lines run with much regularity, and those on the south give evidence of a bold slope continuing downwards far in that direc- tion. It appears that the London syncline has come into existence in an area that was long one of elevation, and that the Wealden anticline has been superimposed upon a region of depression. It was further pointed out that, for a continuance of these investigations, we are dependent upon the making of borings for coal or water; but that no machinery has been created for the systematic registration of borings, notwithstanding the recommendation made in the Report of the Royal Commission on Coal Supplies. The information gained in a borehole may come to hand by chance, or it may be lost. Frequently no permanent record is kept of the site, diameter, or depth of boreholes. It was noted with pleasure that a precise levelling is being carried out by the Ordnance Survey to replace the levelling made in 1841 to 1859, which was not of modern precision, and was recorded by marks which were not permanent. It was pointed out that in work of the precision contemplated, factors of unknown value may have to be taken into account, such for example as earth-tides or the effect of the oceanic tide upon coastal regions, but more especially the variations in gravity which are known to exist, although they have never been systematically examined in the British Isles.