Exploration and Exploitation of Hard Coking Coal in Kianga-Moura Field

Abstract

Owing to a very limited amount of hard coking coal production in Japan, Japanese Steel Mills have been constantly seeking nearer and adequate supply source for that kind of coals at cheaper prices. They have been producing hard cokes by blending domestic soft coking coals with imported coals of which American coals were dominant until 1955 or so.
In order to fulfill these demands and upon request of the Mitsui & Co., Ltd., we have paid keen attention and made studies of the Kianga-Moura Field in Central Queensland, Australia. Through our first field survey from January to April, 1959, we gained the followinge knowledge which lead us to the conclusion as mentioned below.
(1) In Baralaba, the northern extremity of this field, occurence of anthracite had been reported in 1889 and since then the mines were opened. Many prospecting works were carried out to disclose the geological features of coal seams in and around the area. The results revealed that the coal is semianthracite or anthracite containing 10% or less volatile matter, and that the structure is somewhat contorted with NW-SE faults and folds.
(2) In Kianga, southern sector of the field, the Thiess Bros. (Qld.) Pty., Ltd., disclosed the coal seam in box-cut after prospecting by drillings. Coal is soft coking coal with 34% or more volatile matter. The coal seam has a gentle westward dip of 6-8 degrees.
(3) Judging from the geological features of the above two areas, the coal seams of both areas seem to occur in the same horizon or nearly in the same horizon.
(4) The difference in coal quality between Baralaba and Kianga is thought to be closely related to the tectonic movement by which the complicated structure of the Baralaba area was brought about.
(5) The above-mentioned, geological assumption leads to a conclusion that medium or low volatile coal with a possibility of hard coking coal, may be concealed underneath the vast uninvestigated plain between Baralaba and Kianga, covering a distance of 60 km.
From the said point of view, the second prospecting work was commenced in June, 1959 to search for hard coking coal required by the Japanese Steel Mills, with the cooperation and support of the Thiess Bros. and Mitsui & Co. Strenuous efforts revealed that our geological conjecture was right, that is, volatiles in coal seams decrease from south to north, and the samples extracted from a trial shaft at Moura, the central part of the field that was selected by us as a hopeful place for aimed coal, of large reserves, were proved to be hard coking after many tests by the Japanses Steel Mills. This was in November of 1960.
Exploitation of the Moura Mine was thus inauguarated in January of the following year and the first shipment of the Moura un-washed coal was delivered to Hirohata of the Fuji Steel Mill in August. The development has since progressed in rapid strides. In the fisycal year of 1964, the mine is to offer a total output of one million tons of hard coking coal with low sulpher content (less than 0.5%) and low ash content (less than 6%) to the Japanese Steel Mills, at cheaper price than other Australian coals, not to mention American coals. Furthermore, a bright future was promised. A long-term contract for thirty million tons of coal in thirteen years from 1965 was concluded between the Japanese Steel Mills and the Thiess-Peabody-Mitsui Coal Co., operator of the Moura Mine.
This paper deals with the methods of prospecting, such as geological field investigation, surveying, aerial photograph interpretation, as well as drilling and sampling. It also describes a brief history and the present status of the Moura Mine.