TINSTONE CONCENTRATES ANALYSED
Eleven specimens of tinstone concentrates from the Zagi River, south of Bauchi, from Bula, Tilde, and the river beyond Joss were forwarded to the Imperial Institute, and with only one exception were found upon analysis to contain tin in quantities of from mere traces up to 80.85 per cent, of tin oxide, equivalent to 63.5 per cent. of metallic tin in the concentrate.
The official general remarks on the specimens analysed were as follows:
“Most of the concentrates were obtained from the plateaux of Tilde, Rukuba, Joss, and Ngell. On the first three of these the principal surveyor reports that the Niger Company has prospecting camps. The finest grained tinstone is found on the Tilde plateau, the coarser material coming from Joss and Ngell. The tinstone is said to be irregularly distributed, and adjoining pits may furnish such different yields as 10 lbs., or less, and 400 lbs. per ton on gravel worked. The average yield at the Rukuba camp is 25 lbs. per ton. The present works, it is stated, are all in the near neighbourhood of the river Delimi, but it appears that the gravels are more or less rich in tin over the whole surface of the plateau. The river-beds in some cases contain valuable tinstone-bearing gravels, as is shown by the results of the analysis of the concentrate from the river-bed at Tilde, which contained 68 per cent. of tinstone. That from beyond Joss contained only 40 per cent. of tinstone, possibly owing to the difficulty of separating the ilmenite from the tinstone by washing. The concentrate from the Kende River consisted almost entirely of ilmenite. The presence of the latter mineral in the stream beds will introduce a difficulty in the concentration of the tinstone, as it is not readily distinguishable by inspection from tinstone, and collects with it in the first concentration.
“The results so far obtained show that tinstone is widely distributed in the province of Bauchi in the alluvium of both the high and low plateaux. As these tinstone districts are in process of being prospected, it is scarcely worth while to discuss the commercial value of the tin concentrates here, but it may be pointed out that several of these concentrates contain monazite, and this may be worth recovering. The amount of monazite present is usually small, and it is scarcely likely that its recovery under present circumstances would pay for the working of an electro-magnetic concentrator, which would be required to effect its separation. If, however, it becomes necessary to use such concentrators in order to separate the ilmenite, which occurs with the tinstone, then it would probably be worth while to recover the monazite as a by-product.
“The question of the origin of the tinstone occurring in this region is of great interest, and the officers of the Survey propose to devote further attention to the subject.”
The Colonial Report for 1907-8 carried us no further, as the third Survey party which arrived in the country in December 1907 were still upon their seven months expedition, and the results of their work had not been received. The report referred, however, to the fact that the Niger Company, continuing its work on its licensed area in the Bauchi Province, were exporting black tin to the amount of 500 tons per annum, and added: “The main difficulty in the development of this promising industry is its situation. With the construction of the railway through Zaria it should be possible to place the mines in close connection with it by means of a road, which should also serve the Bauchi Province.”
THE REPORTS OF EXPERTS
In one of his reports on the Bauchi tin area, Mr. Lush says: