IX, A, 3 Dalburg and Pratt: Iron Ores of Bulacan 245 



who are also slag men {escoriadores) ; and 4 blower men {jila- 

 dores). The success of the operation depends absolutely upon 

 the maestro; competent maestros are scarce and comparatively 

 well paid, although the rate of payment is based upon the 

 quantity of iron produced. The mold men are called upon only, 

 at intervals to attend the pouring, empty the molds, or remove 

 the slag, but they work day and night as do also the blower 

 men. In addition to this smelter force, laborers are required 

 for cutting wood, burning charcoal, and for breaking up the 

 ore, and carriers (cargadores) are necessary for bringing the 

 ore from the mine (tibagan) and the charcoal from the kiln to 

 the smelter, for transporting the finished product from the 

 smelter to town, and for bringing in food supplies. 



When it is desired to blow in a recently constructed or repaired 

 furnace, a slow fire is started in the crucible and allowed to burn 

 for several hours; then charcoal is added until the crucible is 

 filled and a light blast applied. About twenty-four hours after 

 the fire is kindled, the blast is increased and a small quantity of 

 ore together with more charcoal is charged in at the top of the 

 furnace. Increasingly larger charges are now added at intervals 

 until the operation is normal and the furnace is in full blast. 

 Afterwards, ore and charcoal are charged together at intervals 

 of from one to five hours depending on the rate at which the 

 iron comes down. The average charge consists of 43 kilograms 

 of charcoal and 25 kilograms of ore. Charcoal and ore are each 

 distributed evenly over the top of the burden. The ore is broken 

 into pieces with a maximum diameter of about 2 centimeters. 



When the furnace is working normally, iron is tapped off 

 from two to five times per shift. As soon as the reduction of 

 the ore begins, the lining of the crucible is attacked and eaten 

 away to supply the necessary flux for the slag. In this way 

 a small depression below the level of the runner is very soon 

 formed in which the liquid iron collects. In tapping, the clay 

 bridge with which the tap hole is partly closed between tap- 

 pings — although for some reason the tap hole is always left 

 partly open and at each stroke of the blower a tongue of flame 

 rushes through it — is removed, and the maestro with a long iron 

 rod proceeds to pull out first the ropy, viscous slag which is 

 floating on the iron in the bottom of the crucible. As the slag 

 is drawn forth, it is allowed to fall into the ladle which is thus 

 preheated before it receives the iron. The slag is pasty enough 

 to adhere to the end of the rod, and the maestro, working the 

 last of it into a ball, improvises a rake with which he draws 



