652 REVIEWS 



The Mineral Resources of the Philippine Islands for the Years igiy 

 and I pi 8. Contributors: Elmer D. Merrill, Victorla.no 

 Elicano, Leopoldo a. Faustino, W. H. Overbeck, and T. 

 Dar Juan. Issued by the Division of Mines, Bureau of 

 Science, Bureau of Printing, Government of the PhiHppine 

 Islands, Manila, 1920. Pp. 75, pis. 8, tables 12, and analyses. 



This issue of Mineral Resources of the Philippine Islands deals with 

 the years 191 7-1 8, following the plan expressed in the first issue of 1908, 

 which was continued by annual publications until 1916. Of great 

 interest in the publication under review is the increase in the importance 

 of coal, the slump in gold mining, the appearance of asbestos as a mineral 

 product of the Islands, and the discovery of more deposits of iron. 

 Lesser resources treated are sulphur, manganese, and asphalt. The gold 

 production in 1917 was about 1,990,000 grams; in 1918 it was about 

 50,000 units less. Silver production increased from 81,000 odd fine 

 grams in 1917 to 128,000-odd in 1918. A still greater advance is recorded 

 in the coal production — from 5,000 tons (round numbers) in 191 7, to 

 15,000 tons in 19 18. Since the year 1907 there has been a steady increase 

 in mineral yield except in 19 10. 



In spite of the increasing gold production of the Islands, it must be 

 admitted that gold mining is still in the formative stage. The largest 

 production comes from Masbate and the Mountain Provinces, and the 

 largest single mine is the Benguet Consolidated Mining Company, in 

 the Mountain Province district. 



Three sources of iron ore have been exploited in the islands, and 

 magnetite sand, briquetted, is also being experimented with. Lead and 

 zinc deposits in Marinduque Island are described. They are fissure 

 veins, 4 to 10 feet wide, running as high as 60 per cent lead or 45 per cent 

 zinc; the minerals are galena and sphalerite, the gangue is quarts, and 

 the country rock andesite. Manganese has been produced to some sHght 

 extent, and copper is mined in Mancayan. 



Most Philippine coal is really lignite, but good bituminous coal is 

 known from Polillo Island and in the Zamboango district. At the close 

 of 1918 twenty- three mines were producing coal. In the better mines 

 a modified room and pillar method is used, the room being also an entry. 

 Considerable waste, especially on the part of small operators, is the rule. 

 Mine gases are rare, the walls are good, and ventilation problems in 

 these shallow mines are simple; transportation, however, is a real diffi- 

 culty in coal mining. An interesting feature of coal production is the 

 development of producer gas plants on the Islands. 



