MINING 



out of employment. This difficulty 

 is provided for in the various Acts 

 which allow persons partly in- 

 capacitated to be paid at rates 

 below the minima. The same 

 principle is also introduced with 

 regard to juvenile workers and 

 learners ; the Trade Boards Act, 

 for instance, allows them to be 

 employed at lower rates. In 1920, 



5434 



in connexion with the strike of the 

 agents of the Pearl Insurance Co., 

 it was generally recognized that 

 3 per week was a minimum wage 

 for an adult male worker. The 

 principle of the minimum wage is 

 also enforced in Canada, Australia, 

 and other parts of the British 

 Empire. See Cost of Living ; 

 Sweating ; Wages. 



MINING: OLD AND MODERN METHODS 



Henry Louis, M.A.. D.Sc.. Prof, of Mining, Armstrong Coll., Newcastle 



See in connexion with this general sketch the articles Coal, Gold, 



Lead, Tin, etc. See also Bord and Pillar ; Cage ; Longwall ; 



Prospecting : and other subjects connected with mining operations ; 



Geology ; Metallurgy ; and Mineralogy 



The art of mining, in its widest 

 sense, is the art of extracting 

 mineral substances of intrinsic 

 value from the crust of the earth, 

 and rendering them marketable. 

 The word mineral is here used in 

 its legal and commercial sense, and 

 not as defined by mineralogists ; 

 furthermore, the word extracting is 

 not intended to apply merely to the 

 removal of the mineral, but to all 

 the operations incidental to the ex- 

 traction, and further, it is ap- 

 plied so broadly as to include not 

 merely the mechanical act of sever- 

 ing the mineral from its deposit in 

 the earth's crust, but also to cases 

 where such severing is performed 

 quite indirectly. For example, 

 boring for oil is included under the 

 general head of mining. 



Mining must have been amongst 

 the earliest of the technical arts. 

 The ancient Greeks were skilled 

 miners as well as metallurgists, and 

 in their time special legislation was 

 enacted to regulate mining, show- 

 ing that the industry was one 

 of considerable importance. In 

 Roman times mining was carried 

 on extensively throughout all 

 Roman colonies, and Central 

 Europe in particular was the seat 

 of an important mining industry. 

 In Britain mining must have been 

 pursued vigorously even before the 

 Roman occupation ; the fact that 

 the Phoenicians traded to Cornwall 

 for tin is quite generally admitted, 

 while evidence of the mineral 

 wealth of Britain is to be found in 

 Tacitus and other Roman writers. 



Early Mining 



The first systematic description 

 of mining methods is that given by 

 Georgius Agricola, manager of the 

 mines of the Electorate of Saxony, 

 whose De Re Metallica was pub- 

 lished in 1556. The miner's tools 

 were picks and pointed bars for 

 working soft ground, and wedges 

 and hammers for harder ground, 

 while the hardest rocks were at- 

 tacked by firesetting. This process 

 consisted of laying a great fire of 



wooden billets against the face of 

 the rock to be worked, the flames 

 being directed on to the rock. 

 When this had been sufficiently 

 heated, the fire was raked back and 

 water thrown on the heated sur- 

 face ; the latter was thus shattered 

 and fissured sufficiently to enable it 

 to be broken out by means of 

 wedges ; when the solid face was 

 again reached, the operation was 

 repeated, and so on. This method 

 continued in limited use in 

 Southern Norway until as recently 

 as 1884. 



Use of Gunpowder 



Meanwhile, however, the first 

 great improvement, that may be 

 regarded as the commencement of 

 modern methods, had been made, 

 namely, the application of gun- 

 powder to the blasting of rocks. 

 Gunpowder does not seem to have 

 been used for blasting until 1613, 

 when it was employed for this pur- 

 pose in Saxon}'. It continued to be 

 the only explosive used until 

 Schonbein discovered gun-cotton 

 in 1846, while in the year following 

 Sobrero discovered nitro-glycerine ; 

 these substances were not used at 

 all extensively until Nobel pro- 

 duced dynamite in 1866 and blast- 

 ing gelatine in 1875. Meanwhile 

 Bickford had rendered all blasting 

 easier and safer by the invention of 

 the safety fuse in 1831, and electric 

 shot firing, first used in mines about 

 1870, contributed still further to 

 the development of this branch of 

 the mining industry. 



Long before this, however, the 

 steam engine had been invented. 

 Its first use in mines is said to 

 date from 1711, and it has affected 

 every aspect of mining engineering; 

 in particular it has led to the em- 

 ployment of mechanical means of 

 getting mineral, as witness the rock 

 drill and the mechanical coal- 

 cutter. The first conception of a 

 mechanical drill was due to an 

 American, Fowle, who patented 

 such a machine in 1871, but it was 

 first really employed by Sommeil- 

 ler at the Mont Cenis Tunnel in 



MINING 



1861 ; two years later it was ap- 

 plied to mining at Moresnet in Bel- 

 gium, and mechanical drilling in all 

 its different forms is to-day an 

 essential in mining operations. 



Coal-cutting seems to have been 

 attempted much earlier ; the first 

 record of an attempt at mechanical 

 coal-cutting was a patent taken out 

 by Menzies in 1761, which was not, 

 however, successful. He was fol- 

 lowed by a number of other inven- 

 tors, and the prototype of the 

 machines in use to-day appeared 

 soon after 1850 ; the first disk ma- 

 chine is said to have been made in 

 1851, the chain machine in 1853, 

 and the bar machine in 1856. 



The general result of these great 

 modifications, the use of explosives 

 and of mechanical power, has been 

 to bring about the present aspect of 

 the mining industry, namely inten- 

 sive mining, where the object 

 aimed at throughout is that of pro- 

 duction on the largest possible 

 scale. Until about 1870 mining 

 was practically confined to rich de- 

 posits, or such as could be worked 

 on a small scale with a minimum of 

 expense. Modern mining aims at 

 the working of low-grade or poorer 

 deposits, utilising mechanical 

 means to the utmost in order to 

 reduce working costs. 



Principles of Modern Mining 

 Modern mining has thus become 

 an exceedingly complex art. It 

 includes : 



1. Prospecting or searching for 

 minerals, including, of course, pro- 

 specting by means of boreholes. 



2. Opening up mineral deposits 

 by means of shafts or adits as may 

 be necessary. 



3. Exploitation or the getting of 

 minerals properly speaking, cover- 

 ing all methods of getting by hand 

 and machinery, dredging, blasting, 

 etc., as well as the methods of lay- 

 ing out the mine in order that all 

 the various operations may be 

 performed most economically. 



4. Transportation, covering the 

 various methods employed for 

 transporting the broken mineral to 

 the surface. 



5. Keeping the workings free 

 from foul air and water, this cover- 

 ing the subjects of ventilation and 

 drainage; under this head may 

 also be considered all questions re- 

 lating to the health and safety of 

 miners, the lighting of mines, and 

 prevention of colliery explosions. 



6. Mineral after it has been ex- 

 tracted is only exceptionally clean 

 enough to be marketable, and it 

 usually has to undergo an opera- 

 tion, or more often a series of oper- 

 ations, to fit it for the market ; 

 these operations are included under 

 the term " dressing " ; in the case 

 of coal this is often spoken of as 



