X, A, 5 Pratt: Iron Ore on Calambayanga Island 331 



where there are conspicuous outcrops. The strike is about north 5" 

 west. This ore body has a width of as much as 13 meters at several 

 places. Smaller outcrops occur near by. The ore is high grade hematite 

 and is a workable deposit containing an immense tonnage. 



Rinne, previously quoted, found that the blocks of ore at 

 Bato-bolani were distributed over an area 200 meters (650 feet) 

 wide by 400 meters (1,300 feet) long. He questioned the popular 

 belief that the whole mountain was iron ore, however. 



The area on Calambayanga Island over which blocks of iron 

 ore are distributed is roughly 500 meters (1,650 feet) long and 

 200 meters (650 feet) wide, and blocks of the largest size are 

 found all the way from sea level up to an elevation of 70 meters. 

 There is every evidence that these great masses of ore have not 

 been transported far; they must be practically in place. But 

 from the nature of the ore deposit, it is obviously not safe to 

 assume that beneath the surface there is a solid body of ore 

 with dimensions equal to that of the area over which the surface 

 blocks are scattered. The shape of the ore body may be very 

 irregular, and without more data than is at present available 

 no definite estimate of the quantity of ore can be made. If 

 the ore deposit originated as suggested in this paper, the ore 

 should persist with depth — that is, it should not be confined to 

 the present surface. However, its vertical dimensions, like its 

 horizontal dimensions, are probably irregular and cannot be 

 estimated. 



The ore on the island appears to be sufficient in quantity to 

 be commercially important. It is probable that there is even 

 a greater quantity of ore on the adjacent mainland, and the 

 smaller island of ore to the west of a line from Calambayanga 

 Island to the ore on the mainland is evidence of even wider 

 ramifications of the mineralization. The ore in sight is un- 

 doubtedly to be estimated in hundreds of thousands of tons, but 

 the total quantity of ore available is undetermined. It is impos- 

 sible to escape the conviction, however, that the surface indica- 

 tions warrant capital in making the exploration requisite to 

 determine the extent of the ore body. Preliminary exploration 

 could probably be accomplished best by diamond drilling, and the 

 expense of drilling at this site should be close to the minimum 

 for this class of exploration. 



