X, A, 5 Pratt and Lednicky: Iron Ore in Surigao 343 



obtained by dividing the whole deposit into two classes — good 

 areas and poor areas — the boundaries of which were determined 

 by our observations in the field. This classification applies to 

 the nature of the deposit, not to the character of the ore. The 

 average depth of ore in each area is estimated from the results 

 of groups of drill holes in that area. The various areas over 

 which the ore is of good depth (indicated in Plate I) are again 

 divided into two groups, one of which includes two areas which 

 are accessible from Dahikan Bay and the other includes five 

 areas which must be exploited from another base — probably 

 from Taganito. 



The total area of the ore deposit is about 100 square kilo- 

 meters. This figure is less than the area of the deposit as 

 outlined in Plate I by reason of the exclusion of several patches 

 of alluvium and some of the steeper slopes which are not covered 

 by ore. Probably 30 per cent of the deposit, exclusive of the 

 good areas, is so inaccessible and so covered with forest that 

 the ore upon it would have no commercial importance. 



The areas classed as good aggregate 30 square kilometers. 

 They include flat-lying portions of the deposit over which the 

 ore is known to be of good depth. The two areas which are 

 accessible from Dahikan Bay, the most feasible base of oper- 

 ations, contain 15 square kilometers. 



Four groups of drill holes were located in the areas classed 

 as good: One group of 56 holes placed regularly (some 150 

 meters, some 300 meters, and some 500 meters apart) in the 

 vicinity of Dahikan Bay; one group of 2 holes in the vicinity 

 of Hinadkaban Bay; and one group of 23 holes, 300 meters 

 apart, in the vicinity of Taganito. One group of 17 holes, 

 spaced at 150-meter intervals, was located in a poor area near 

 Dahikan Bay. It may be objected with some reason that the 

 number of holes and the area over which they are distributed 

 are both limited and are hardly a sufficient basis for judging 

 the whole ore deposit. The result which we obtained, however, 

 both on the chemical character and the thickness of the ore, 

 from widely separated groups of holes, are uniform enough 

 to make us confident of the approximate correctness of our results 

 considered as preliminary estimates. At any rate, the reader, 

 knowing the basis upon which the estimates are made, will 

 draw his own conclusions as to their accuracy. 



Of the drill holes located in good areas, 6.8 per cent fell on 

 bare rock, thus encountering no ore; 28.8 per cent encountered 

 from 0.5 to 3 meters of ore; 34.3 per cent encountered from 



