Mr. Buddle on Mining Records. 333 



perseverance, which were so discouraging during the first few years, it be- 

 came one of the most prosperous and lucrative undertakings in the 

 country. 



10. — System of Ventilation. 



The workings were ventilated strictly according to Mr. Spedding's sys- 

 tem of shething and coursing — generally in sheths of two and two. It was, 

 however, found necessary to limit the length of the sheths to 10, 12, or 16 

 pillars, say from 220 to 352 yards, as a greater length was found to load 

 the air more than was prudent for the ordinary coal-work to be carried for- 

 ward in. The sheths were, therefore, shortened by making lonings at the 

 intervals mentioned, so as always to give the front of working places the 

 the first of the air. 



This mode of proceeding was continued till about the year 1810, some- 

 time after the working of pillars had commenced in the A, B, C, D, E, and 

 F Pits, but the G Pit being a separate winning, and not having any under- 

 ground communication whatever at that time with those pits, I established 

 my system of " pannel-work" and double ventilation in this pit. 



The system of double ventilation was also adopted in the other pits, 

 when the working of the pillars could not be carried on with safety under 

 the old system. 



What I call the system of double ventilation consists in dividing the 

 principal current of atmospherical air, at the bottom of the down-cast shaft, 

 or in any part of the workings into two or more currents ; which currents 

 may be earned separately, through different divisions of the workings, and 

 discharged by separate passages into the up-cast shaft. 



Those discharging drifts into the up-cast shaft are so constructed as to 

 admit of having furnaces for the purpose of rarefaction placed in them* 

 Experience has proved that a good furnace placed in one of these drifts 

 rarefies the air in the up-cast shaft sufficiently to induce a powerful current 

 of air from the other drifts, which have no furnaces in them. It is, there- 

 fore, only necessaiy to supply the burning furnace with a current of inex- 

 plosive air, while the return currents, after having become loaded to the 

 firing point by traversing the inflammable parts of the workings, pass 



vol. II. 3 it 



