The impacts of guano and rock phosphate mining - The Great Barrier Reef: An Environmental History - page 161

Phosphate mining at Holbourne Island commenced in 1918, but the grade of
the phosphate was found to be too low to supply the inter-state and international
markets profitably . 9 However, the material was suitable for local markets, and
phosphate was transported from the island via Bowen to Brisbane and Townsville
for processing. One source recorded the import of 25 tons 4 cwt of phosphate to
Bowen Harbour by the A.U.S.N. Co. Ltd in May 1918 . 10 A total of 450 tons of
material was removed from the island in 1918; in 1919, the amount increased to
850 tons. However, in 1920 the annual yield declined to 450 tons, and in 1921
only 369 tons 10 cwt (valued at £1,570) were shipped (Linedale, 1922, p600; The
Bowen Independent , 29 January 1971, p4). Hence, the industry was short-lived
and the company ceased its operations at the end of 1921. The following factors
contributed to the decline of the industry:
(a) high production costs due to unreliable shipping;
(b) the high cost of freight to the mainland;
(c) the lack of drying facilities on the island, increasing the weight of the
shipments;
(d) labour and provisioning difficulties;
(e) the low tonnage output; and
(f) a high proportion of lime contained in the Holbourne Island phosphate,
which made the cost of manufacturing superphosphate too high, in
comparison with other sources.
( The Bowen Independent , 29 January 1971, p4)
After 1921, no further working of phosphate took place at Holbourne Island;
subsequently, phosphate was imported from Nauru and Ocean Islands instead
and, in the 1970s, the Holbourne Island deposits were declared not commercially
viable (QEPA, 2003b) . 11 Subsequently, Hopley (1982, p376) confirmed that
evidence of the rock phosphate quarry remained in the landscape of Holbourne
Island.
Summary
Profound changes in the landscapes of some of the Great Barrier Reef's islands
and cays, spanning almost the entire period of European settlement in the
region, have been described in this chapter. Island landscapes were modified by
the construction of the navigation beacon at Raine Island, in 1844, and as a
result of guano and rock phosphate mining at various other islands and cays.
Overall, the impacts sustained in the Great Barrier Reef as a result of guano and
rock phosphate mining were relatively widespread - occurring in at least ten
locations - and prolonged: from 1860 until around 1940. However, those impacts
also varied in their intensity as different mining strategies were adopted, and as
deposits of varying qualities were worked. The earliest instances of guano mining
in the Great Barrier Reef were informal and unlicensed; however, by the 1860s,