340 



The Philippine Journal of Science 



19tS 



The chemical composition of the Surigao ore is shown in the 

 following tables. Table I contains the analysis of a sample taken 

 by Mr. Cameron and an analysis of similar ore from Mayari, 

 Cuba, quoted from Kemp.* 



Table I. — Analysis of iron ore from Surigao Province." 



Constituent. 



Hygroscopic water 



Combined water 



Silica (SiOa) 



Alumina (AI2O3) 



Ferric oxide (Fe203) 



Ferrous oxide (FeO) 



Chromium oxide (CraOs) 



Sulphur 



Phosphorus 



Nickel oxide (NiO) 



Total 



Metallic iron, dry ore 



Metallic iron, ignited ore 



Surigao 



Cuban 



ore. 



ore. 



Per cent. 



Per cent. 



13.50 

 6.60 





11.15 



1.04 



2.26 



10.56 



14.90 



66.80 



68.75 



0.36 



0.77 



1.15 



1.89 



trace 





trace 





none 



0.74 



100.01 



100.46 



54.29 



48.65 



58.20 



54.20 



' Analysis by Francisco Pefia, chemist. Bureau of Science. 



Two other samples submitted by Mr. Cameron contained 51.92 

 and 54.15 per cent, respectively, of metallic iron in the dried 

 ore. 



The determinations appearing in Table II were made upon 

 drill-hole samples taken by us. The figures show the percentage 

 of metallic iron in the dried ore and in the sintered ore. The 

 latter figure is employed for the purpose of making possible a 

 direct comparison of the Surigao ore with the Cuban ore, which 

 is sintered or nodulized before it is smelted. Sintering is a 

 necessary preliminary to the smelting of clayey ores, and the 

 column containing the figures for the iron content of the sintered 

 ore also shows the proportion of iron which a smelter could 

 expect in ore from Surigao. It is assumed that the Surigao ore 

 will reabsorb about the same quantity of moisture after sinter- 

 ing that the Cuban ores do. Kemp ^ states that the nodulized 

 or sintered Cuban ore contains from 3 to 3.5 per cent of water ; 

 therefore the column of percentage of iron in the sintered ore is 

 based on the weight of the ignited ore plus 3.5 per cent for 

 reabsorbed water. 



* Op. cit., 147. 



= 0p. cit., 131. 



