1RODUCTION OF PHOSPHATE ROCK. 
163 
of hard rock exported during 1911 as reported by the producers was 
462,072 tons, as against 461,353 tons during the preceeding year. The 
total amount of hard rock phosphate shipped is in excess of the 
amount mined, indicating a further reduction of the stock on hand. 
PEBBLE PHOSPHATE. 
The production of pebble phosphate, which has steadily in¬ 
creased year by year, shows a further increase during 1911. The 
total output for 1910 was 1,637,709 long tons. The output for 1911 
was 2,020,477 long tons, thus verifying the prediction of a year ago 
that the production of pebble rock during 1911 would exceed 
2,000,000 tons. Seventeen companies operated in the pebble phos¬ 
phate fields, although only sixteen were actually producing rock 
during 1911. 
The domestic shipments of land pebble rock during 1911 
amounted to 1,274,056 tons, as against 703,589 tons exported, thus 
contrasting with the hard rock phosphate practically all of which is 
exported. The domestic shipments of pebble rock during 1910 
amounted to 995,728 long tons, while the amount exported was 
606,110 long tons. These figures indicate an increased percentage 
of rock remaining in the United States. 
The statistics on the production and shipments of phosphate 
rock have been supplied direct by the producers, and are complete 
for all plants operating in Florida. 
Thirty-one companies in all were engaged in mining phosphate 
in Florida during 1911. In addition to these the Amalgamated 
Phosphate Company began the construction of a plant for the pro¬ 
duction of pebble phosphate. 
