'THE GEOLOGY AND MINERAL RESOURCES OF DHUFAR PROVINCE, MUSCAT AND OMAN' [‎39v] (68/96)

52
Hanun water-hole and camp site) there are bedded middle Kocene
limestones, some with a strong taste of salt, below the Dolomite beds.
An analysis of the limestone which tastes of salt (Sodium chloride)
was analyzed by Messrs. R V. Briggs & Co., Ltd., Calcutta, with the
following results: Calcium carbonate 92-41%, Magnesium carbonate
3-32%, Insolubles (Silica, etc.) 1-26%, Oxide of iron 0-23% and
Alumina 0-17%, and 2-42% of water-soluble matter. This water-
soluble matter (2-42% of the whole limestone) was composed of
Calcium sulphate (0-48%), Magnesium sulphate (0-03%), Magnesium
chloride (0-24%), Sodium chloride (1-67%) and a trace of Potassium
chloride. The limestone itself is of high grade, but I did not collect
the specimen for its quality; but for the salt it contained. Indeed, I
was of the opinion that it was not a particularly high grade lime
stone, and that material of better quality was there present. I was
not interested in the chemical composition (for commercial utilization)
of limestones in the Qarn Shaiba region when there was so much
limestone near and along the coast of Dhufar, including the Miliolitic
limestone of Salalah, etc.
An analysis of a sample of the Miliolitic limestone from between
Salalah and El Balad, made by Messrs. R. V. Briggs, gave:—
Calcium carbonate . . .. . . 90-25%
Calcium sulphate
Magnesium carbonate
Insolubles (Silica, etc.)
Oxide of iron
Alumina
Alkalies, etc.
0-92%
4-55%
3-28%
0-17%
0-31%
0-52%
Limestone of this quality is suitable for the manufacture of
Portland Cement. The Magnesia content would be 2-14% (from
4-55% Magnesium carbonate) and allowing 1 -| tons of limestone
per ton of cement the total Magnesia in the latter would be about
3-2% (which is below the 4% permissible in specifications of the
British Standards Institution). However, while the miliolite lime-
stone might be suitable for making the best quality Portland Cement,
and the quantity is very large, this limestone is not as high in purity
as the saliferous limestone (Nummulitic) from Hanun, and I was
m\seli anxious to locate good quality limestone on, or close to,
the coast for chemical purposes, such as preparing Soda Ash,
Bleaching Powder or in the purification of sugar. I therefore took,
as fairly average samples on the slopes as I descended to the Rizat
spring on the 10 th February (see paragraph 45 ). At the time I was
somewhat disappointed, as the material I was collecting appeared to
be siliceous and inferior-looking to most of the limestones I had
superficially noticed elsewhere in Dhufar. The results of the chemical
analyses made by Messrs. R. V. Briggs & Co., Ltd., are as below:—