1898 - Coalmininghistorypa.org

No. 11. THIRD BITUMINOUS DISTRICT. 345Moditiciilioii of the Single Entry System of Extraelinj;;- the Coal Seamsand the Adoption of Fans Instead of Furnaces for VentilatingPurposes.As a necessai-y evil, tlie single entry system of extracting the coalseam has been adopted at a very large number of the mines in thisdistrict. Its sujtposed cheaimess has been (he great considerationin favor of the adojition of this system and no amount of argunu'ntadvanced to disi>r()ve of this eri-oneous method seems to have mucheffect on the mine managers who cling to the old nu^hods of theirforefathers, rather than fall in with the moic modern and economicones. If this system cannot be eliminated entirely, tlien the nextbest plan would be to oHer some suggestions relative to its modificationor imi)ro\('nient.1st. I would saggiest that wherever the single entry plan has beenadopted, that the entry be driven to its boundary line, followed withan air course, befoie any rooms are allowed to be turned tlierefrom.This work being completed, then begin atthe boundar^^ line to extractall of the coal by sections worked on the retreating system.This can be done either by the pillar and room method, oi' by a modificationof the long wall plan. Ky the adoption of this methodscpieezes would be avoided and efficient ventilation maintained atthe face of the workings.2d. If the above method was too long a st(^p to take for a beginning,they could uu)dify the |)lau and still make a gr^Nit improvement on thepresent one, as follows: Drive the entry with a solid air course on oneside of it as before mentioned, making cut throughs no oftener thanthe extreme limit of the law (as to distance) required, having saidcut throughs so i)laced as to serve the purpose of a room neck whenthe coal would be taken from that side. As the entry w as advancingturn rooms on one side of it only. Before turning any rooms, drive theentry at least one hundred feet. The rooms turned off' the entryshould be driven in couplets or 'triplets, that is, the entry pillarshould only be cutat such distances apart as to serve the purposeof a room neck and as an exit for the wagons to the eiitr}- for thesegroups of rooms, instead of cutting the entry pillar so many timesor making a neck for each room. By this method the entry pillarwould be strengthened very materially, thus avoiding annoying andexpensive scpu'ezes and insuring a greater ^illars would have to be determined by the surioundingnatural conditions. After the coal had all been worked out on theone side of the entry, then the other side could be attacked beginningat the boiindiiiy line and working on the retreating system inlimitedsections until all of the coal was secured. This modification of thesingle entry svstem has in a limited way been tried and it has proven