Rizal Province directory, Volume I.

MINERAL RESOURCES

LIMESTONES
Pure hard crystalline limestone deposits occur in Binangonan and Montalban. In 1914 Binangonan deposit was
utilized for Portland cement manufacture by the Rizal Cement
Company, Limited, under the supervision of Ynchausti and
Company, and at present by the Madrigal and Company. The
Montalban deposit has been quarried and sold as lime. As
early as 1903 limestone claims were stuck in Antipolo and
Morong but none was developed. Beds of oyster and marine
shells are distributed along the coast towns of Manila Bay.
They are exploited only for mortar purposes by the towns of
Malabon, Navotas, and Paraiaque for they are of inferior
quality.
GOLD
Gold speculation has been active since the early years of
American occupation. Lodes were claimed to occur in Montalban, Tanay, San Mateo and Antipolo and places in the Marikina river, but no active operations were attempted. During
the gold rush of 1933 several hundred claims were registered
with the Division of Mineral Resources. The towns of Tanay,
Montalban and Antipolo became the centers of fever heat speculation. Each claim covers an area of 9 hectares.
IRON AND PLATINUM
Iron deposits that occurred in the district of Morong
(Rizal) were first exploited by the Spaniards before they
worked on the ores of Angat and San Miguel de Mayumo of
Bulacan. Iron-ore deposits were known to occur in Pililla,
Tanay, Antipolo and Montalban, but no attention was given
them. In the alluvial deposits of Rizal, native platinum was
reported to have been found in minute flattened grains.
SAND, GRAVEL AND ADOBE STONES
Large quantities of sand and gravel deposits consisting
chiefly of andesitic and basaltic origin are exploited from the
Marikina, Pasig and San Juan rivers. They are dredged or
hand quarried, loaded into bancas and exported to Manila, where
they are used for concrete construction. The quarrying in Talim Island which supplies the city with crushed stone is done
by dynamite blasting and machinery crushing. Adobe stone
is quarried from San Pedro Miakati, Pineda (Pasig), McKinley
and Mandaluyong.
GUANO AND KAOLIN
Guano deposits were reported to exist in Montalban, Tanay, San Mateo, Binangonan, Antipolo and Pasay. No commercial exploitation was done of this fertilizer. In 1912 kaolin
was reported to occur in Montalban.
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