Chapter XIII: Appendix: I

MINERAL RESOURCES

Salt — Iron — Gold — Monazite — Galena — Tinstone.

Detailed information respecting the principal mineral resources of Northern Nigeria will be found in Professor Dunstan’s Reports on the Results of the Mineral Survey.[192] The following is a brief summary of the more important facts.

(1). _Salt._

Salt has long been a staple article of inter-tribal commerce on the middle Benue, and its manufacture has in the past been extensively carried on in the province of Muri. The introduction of European salt has, however, adversely affected the native industry, and salt-making is now confined only to those localities in which the natural conditions are most favourable. In Muri province the salt is prepared by the concentration and evaporation of the waters of weak brine springs which are distributed over a western and an eastern area. In the western area the town of Awe is the centre of the industry, while Akiri and Azara are subordinate in both production and population. (Plate XVIII, Figs. 1, 2.) Keana on the Nassarawa border forms the western limit of the salt- producing area, while Akwana to the south of the Benue marks its southernmost extension. In addition to these towns which still manufacture a surplus for export, salt-making for local purposes is carried on at Kanji, Doya, Abuni, Ribi and Arofu within the same area. At a former period also salt was made at Lafin Gisheri, between Tunga and Ibi, and this locality may be taken to mark the eastern limit of the salt area. In eastern Muri the salt-producing district is of less importance than that in the west. The centres of the industry are Bomanda and Jenoe, but small quantities of salt are also prepared at Jebjeb, Jebero and Langa.

With regard to geological occurrence it is believed, as already indicated, that the weak brine from which the salt is made in Muri province is located within the upper part of the “Muri sandstones” and immediately underneath the passage beds and the Turonian limestone. Mr. Longbottom found that at Awe the springs supplied from the sandstones of the passage beds are entirely free from salt and cease flowing before the end of the dry season, while the neighbouring brine springs which rise from rocks lying below the surface drainage maintain a constant flow throughout the year. Moreover, wherever the shaly bands within the passage beds were pierced by boreholes, the brine rose with a steady flow under considerable pressure. The sandstones and grits underneath the passage beds appear to be saturated with weak brine which is retained, as in a reservoir, by the overlying shales. It is believed that the western and eastern salt-bearing districts form detached and irregular synclinal areas affected by a subordinate folding. The brine springs at Awe, Azara and Bomanda are especially associated with the subordinate anticlinal axes along which the salt-bearing beds within the synclinals approach the surface. Some of the minor salt towns, such as Ribi, Keana and Jenoe, are probably located on or near the outcrop of the salt-bearing beds. Wherever the brine springs are found, bubbles of a colourless gas, probably carbon dioxide, rise with the water. Calcareous incrustations round the orifices of the springs are found at Awe and Jebero. Some of the springs of Awe are, moreover, slightly thermal and possess a temperature a few degrees above sun heat. This is probably to be correlated with the recent volcanic action in the neighbourhood.

Distribution of Salt, Tinstone, Gold and Galena.

MAP No. 4.

London. Macmillan & Co., Ltd.

_Face p._ 266.]

The present springs rise in stream courses and are unavailable during the rainy season. Boring, however, within the synclinal areas would afford a copious and continuous supply. Professor Dunstan has analysed the salt of various localities and discussed the possibilities of increasing the native output. The general weakness of the brine, however, would appear to be unfavourable to European exploitation.

Salt is won from brine pools in south-eastern Bauchi over an extensive belt of country which stretches northward from the Pero Hills and passes to the east of Chongwom and Tangalto. The pools are presumably fed by springs and the salt is said to be abundant and easily prepared. The whole area, however, is very imperfectly known and largely unexplored. Scanty incrustations of natron, utilised by the local herdsmen, are known from the Gongola valley in the neighbourhood of Nafada.

In Bornu salt is made from the ash of the siwak tree (_Salvadora persica_) which grows abundantly on the ancient dunes which fringe the western shore of Chad. The slaves of Mongonu and Musara prepare salt also from the ash of three varieties of grass, “pagam, kalaslim and kanido,” which are found in the immediate neighbourhood of the lake. Over the whole of central Bornu the waters of the wells are charged with salts of soda in very varying amount. The ancient alluvium of Bornu is evidently impregnated with soda, and incrustations are found in places upon the surface of desiccated swamps. Natron pools, similar to those of Manga and presumably fed by springs, are unknown in central Bornu.

In Sokoto province incrustations of salt are found in the dry season at Zauro in the valley of the Gulbin Kebbi, and natron (kungwa) occurs in a similar manner between Gulma and Argungu. Knots and streaks of gypsum are common in the shales and clays around Sokoto, while efflorescences of gypsum and alum are found on the cliffs of Wurnu to the north-east. Scanty incrustations of natron are found upon desiccated swamps in many localities in the provinces of Sokoto, Kano, Zaria and Ilorin, but never in sufficient quantity to give rise to even a native industry. Hausaland has been in the past supplied with salt and natron from Asben, Bilma and Manga in the French Sudan. European salt, however, is rapidly replacing the native article, and many caravans now bring only natron from the north to the markets of Kano.

(2). _Iron._

As in the case of salt, so in the case of iron, the native manufacture has been very largely superseded by the importation of European bar- iron. Only in the more inaccessible districts or in those places where the ore is abundant do the natives still smelt the local ironstones in their primitive fashion. The surface ironstones were at one time generally utilised throughout the Protectorate as a source of iron. The magnetite sands are still washed and smelted by the pagans of the Mumuye hills in eastern Muri, while in northern Nassarawa the Koro tribe around Kao is still noted for its proficiency in the manufacture of iron from the local limonitic ores which occur within the schists in veins of varying thickness.[193] Similar ores occur in veins in the sandstones around Akiri in western Muri, but are no longer utilised by the natives. The oolitic and earthy ironstones of sedimentary origin and of Eocene age give rise to an extensive native industry around Akwi and Ojerami in central Kabba, around Mahorro in eastern Kontagora, around Aliero in southern Sokoto, and around Kantana in southern Bauchi, as well as in the Kerri Kerri country in western Bornu and in the Tagum hills in southern Bornu. So far as European exploitation is concerned, the sedimentary ores of Mt. Patti and the lower Niger are most favourably situated for transport. The ores, however, while abundant, are of a somewhat low grade character and relatively rich in phosphoric acid. Magnetite and hæmatite schists are extensively developed in eastern Kabba, but their composition would render necessary costly crushing and separating processes before the ores could be available for export.[194]

(3). _Gold._

Traces of gold have been found in some of the quartz veins which are so widely distributed throughout the Protectorate, but no payable reefs have yet been discovered. Small quantities of free gold occur in the streams between Koriga and Birnin Gwari in northern Zaria and around Tagum in southern Muri. In Zaria the gold is evidently located within the northern prolongation of the Zungeru belt of slates and schists, and further exploration may possibly lead to valuable discoveries. All the slaty belts already described within the Protectorate are, indeed, worthy of careful prospecting for gold. Small quantities of gold are also found associated with cassiterite in some parts of Bauchi province.

(4). _Monazite._

Monazite is widely distributed throughout the Protectorate, and appears to be a fairly constant constituent of the gneisses and schist. Small quantities are contained in almost every river and stream within the crystalline areas. It has been found most abundantly in central Kabba and in northern Nassarawa, but, so far as known, it occurs nowhere in sufficient quantity to afford any hope of profitable European exploitation.

(5). _Galena._

A slightly argentiferous galena occurs in veins within the Cretaceous rocks around Arofu and Akwana in western Muri, and in the Kudu valley to the west of Jebjeb in northern Muri. In the Arofu district the galena is associated with fluorspar and calcite, and the formation of the veins has been accompanied as already described by much silicification of the adjoining limestones. The Arofu galena is excavated by the natives for use as a cosmetic, and from time to time small pockets of silver are discovered within the veinstuff. To the west of Jebjeb the galena is no longer dug by the natives, and the old workings are now levelled and grassed over. The galena appears to have been associated with quartz, hæmatite and blende, but there is no evidence of silicification of the country rock.

(6). _Cassiterite (Tinstone)._

Tinstone is the most valuable asset of the Protectorate from the point of view of mineral resources. Its occurrence in western Bauchi was known to the natives long before the advent of Europeans. Recent investigation, however, by the Mineral Survey has proved its presence over considerable areas in widely separated localities within the Protectorate. The most extensive area over which tinstone is found in the surface alluvium occurs in western Bauchi, and includes the summit of the plateau and the greater part of its northern margin. The alluvial deposits of Naraguta, which lie within this area, were originally developed by the Niger Co., but have now been acquired by the Consolidated Gold Fields, Ltd. Elsewhere, however, tinstone becomes equally abundant, and there is little doubt that further investigation will reveal many localities within this extensive area in which alluvial workings may be profitably carried on. Several syndicates indeed are now engaged in exploiting certain portions of the tinfield. In the neighbourhood of Ngell the tinstone, accompanied by sulphide ores of copper, zinc and lead, occurs, as already described, in part as a pneumatolytic modification of the Bukuru granite, and in part as a true lode or pegmatitic formation. This particular occurrence is being developed by the Niger Co., but there is every reason to believe that similar occurrences will be found throughout the area as investigation proceeds.

Apart from this extensive tin-field in the centre of the Protectorate, cassiterite is also found in Bauchi province in many places throughout the Ningi and Burra hills, and detailed prospecting will probably here also reveal several payable localities. The completion of the Baro-Kano railway[195] within the next two years will afford an easy means of access to the tin-producing areas of Bauchi, and will at the same time largely overcome the difficulty of transport which is at present the greatest obstacle in the way of the development of the tin fields.

Beyond the limits of Bauchi province small quantities of tinstone have been found in the neighbourhood of Gadama and Fagam on the borders of Bauchi and Kano, around Gantam and Aribi on the Nassarawa tableland as well as on the eastern slopes of the Vere hills in Yola, the western slopes of the Shebshi hills in southern Muri, and in the neighbourhood of Eri in eastern Ilorin. In the latter locality the tinstone was found to be derived from a richly stanniferous pegmatite vein, but the actual extent and possibilities of the occurrence are as yet unknown. The same may be said also of the other localities indicated, and there can be little doubt that all of them are worthy of further investigation. Tinstone has been reported to occur abundantly in the Mada country in eastern Nassarawa, but this discovery likewise awaits confirmation.

[Footnote 192: Dunstan, _Col. Reps._ (_Miscell._), Nos. 32 (1906), 46 (1908), 47 (1908). A fourth report on the results of the Mineral Survey will shortly be issued.]

[Footnote 193: Sir William Wallace has reported an extensive native iron industry at Fawa in Katsina, where the ore appears to occur in a similar manner to that in the neighbourhood of Kao.—_G. J._, VIII., 1896.]

[Footnote 194: In _The Iron Ore Resources of the World_, Vol. II., 1910, p. 1029, Dr. J. W. Evans has given a _résumé_ of the results of the investigations of the Mineral Survey into the extent and value of the ferruginous deposits of Northern Nigeria.]

[Footnote 195: And the branch line to Leri in Zaria province.]