First Report On The Geology And Mineral Resources Of British Somaliland With Map

4. GALENA

Samples of galena collected by Somalis were sent from Berbera to the Imperial Institute for analysis in 1920, but, beyond the fact that they had been obtained in the Warsangeli District in the north-east of the Protectorate, and the results of the analyses, no reliable information about the occurrence was obtainable. By means of enquiries from the District Commissioner at Las Gori and with the help of local guides and tribesmen, two occurrences of the mineral were found by the writer:

(1) At Unkah, about 1 1/4 miles north-north-west (bearing 336°) of Inda Ad, south-east of Las Gori.

(2) At Kul, about 13 miles east of Inda Ad, and about 2 miles up the Kul tug, which flows from the Eocene limestone escarpment.

Unkah is about two camel-treks and Kul about three south-east of Las Gori, and Kul is about 16 miles south of Ras Adaddo on the coast.

(1) At Unkah, the galena was found on the top of a small saddle just to the right of the track from Inda Ad and on the site of a small Somali karia (collection of huts). It appears to have been first obtained by a Somali woman engaged in erecting a hut. Under the existing conditions as regards time, labour and implements, and, on account of the presence of the karia, it was not possible to open out the occurrence to any appreciable extent, but, with considerable difficulty, a hole was sunk to a depth of about two feet, a trench was cut along the strike of the slates for about fifteen feet, and a crosscut about eighteen inches wide was put in across the strike. From this amount of work it was apparent that the galena occurs in the old series of (probably) Palaeozoic slates, more or less sporadically as slugs between the laminae of slate and in the laminae themselves. It is associated with chalcedonic quartz and with barite. The mineralization extends parallel to the strike of the slates for a proved length of about fifteen feet, for a proved width of about eighteen inches and for an unknown depth. To the north-west and to the south-east of the karia, the lode or vein was cut off by a dyke of a grey, very much carbonated and decomposed rock of a porphyritic character, standing up as small bluffs. No solid mass of galena was seen, but of course the amount of work done on the deposit was quite insufficient to determine accurately its value or possibilities. An effort was made to find the continuation of the lode to the north-west and to the south-east beyond the intrusive bluffs, but, owing to the surface being obscured by debris and undergrowth, it was not possible in the time available to ascertain whether it continued on or not.

Specimens of the ore were collected and were assayed at the Imperial Institute.

The results were:

The amount of lead present is quite satisfactory from a commercial standpoint, but the amount of silver is not large enough to render the metal a valuable byeproduct.

(2) At Kul, the galena occurs near the base of the Eocene limestone scarp in a small hill composed of slates similar to those at Unkah. It was originally found more than twenty years ago, apparently by Colonel Ashby in a small hole near the bank of Kul tug. In the hole, the mineral occurs in association with barite along a cleavage plane in the slates, in part as slugs, in part as small crystals, strings and veinlets in the barite. On examination of the hill —which was rendered difficult by continuous rain over a period of five days—it was found that the galena and associated barite could be traced from one side of the hill over the top to the other side owing to the fact that the minerals form a well-defined white vein and that numerous fragments of galena, and of barite enclosing galena, lie scattered over the surface. The vein is from three to four feet in thickness and consists in places of two, in places of three parallel veinlets which occupy cleavage cracks in the slate running in a north-easterly direction. On each side of the veinlets, the slate is ferruginous. The strike of the slates is north-north-west—south-south-east, the direction of dip is about N. 82° E. and the amount of dip varies between 35° and 40°. Several small holes had previously been sunk along the course of the main vein, probably also by Colonel Ashby, but these were so overgrown by scrub that, under the existing conditions, little information could be obtained from them. Though a few crystals were got in the first hole, the galena of the main vein is largely a finely granular, somewhat friable variety, in patches, strings, or streaks in the barite. The occurrence of the mineral, however, so far as could be seen, is sporadic, no large deposit was met with, and the veins contain, probably, too small an amount of ore to be of much value in themselves.

An analysis of a sample chipped from the barite mixture, but containing a considerable amount of barite, was made at the Imperial Institute, with the following results:

The low percentage of lead present is, of course, due to the amount of associated barite in the sample, and it is probable that had the lead ore only been assayed the percentage of silver obtained would have been higher.

In view of the above facts and the comparative inaccessibility of the locality, the occurrence is of little economic importance except as an indication of mineralization of the country, of the presence of galena over a wide area, and of the presence of that particular variety of galena—the finely granular or indistinctly crystallized—which, according to experience elsewhere, usually contains a greater proportion of silver than the coarsely crystalline material. The occurrence is somewhat similar to that at Unkah, but at Unkah there is more galena and much less barite, and the locality is readily accessible.

The deposits are probably to be classified amongst the so-called disseminated leadore bodies which are the result of the abstraction of lead from waters circulating along channels and bedding-planes or from solutions rising under hydrostatic pressure along more or less vertical channels.

The significance of the discovery of these deposits is that they indicate the possibility of the presence of sulphide ores in the Black Slate Series. This series has not hitherto been known to occur in the Protectorate, and in no other part of the latter so far examined, except at Dobo in Western Somaliland where molybdenite occurs in granite pegmatite, have sulphide ores been found. It is known that in Italian Somaliland, some miles to the east, both galena and cinnabar are present. As, in all probability, both these minerals have been obtained in an extension of the Black Slate formation, and as galena is present in British territory, there would appear to be a reasonable chance of cinnabar also being found in it. That mercury is known to the Somalis in the east is shown by the fact that they have their own name for it—biyu lagh (silver water). The writer, however, was unable at short notice to get a native who knew of any occurrence of it.

Moreover, it is to be noted that these two localities were found by Somalis quite by accident during the setting-up of huts. It is, therefore, more than likely that other deposits of the mineral exist in the Warsangeli district in the Black Slates, particularly as Unkah and Kul are situated about 13 miles apart.

As statements had been repeatedly made in Berbera that an old disused lead mine existed at Gedweda, between Hais and Las Gori, a search was made for the mine in the hills behind this place. The alleged mine proved to be a subterranean cave in Eocene limestone, of the same origin as similar caves in limestone elsewhere. Some vertical solution-channels of cylindrical form simulate small shafts. No galena or other lead ore, in fact no ore of any kind, was found in any part of the cave.

5. SALT

Salt has been produced for many years in brine pans or pools round Zeyla, and it has been found in a natural state in a hill one-and-a-half miles south of Hais, and, according to report, in Daga Der and Darraboh Hills, twenty-five miles east of Berbera and thirty-five miles north-east of Dagaha Shabell.

Formerly, there was a considerable trade in Zeyla salt inland to Abyssinia and overseas by export from Zeyla, but of late years this trade has fallen off very considerably and there is a danger of its ceasing altogether. The reasons for this are clear and may be set out briefly.

The industry has been all along in the hands of Somalis, Arabs or Indians, and the methods originally adopted many years ago have never been altered. When there was a good market for the salt no efforts were ever made to bring to its production up-to-date methods; no analysis of the product was obtained to ascertain the impurities present, the faults of the article, and the best means of getting rid of them and bringing the salt to the highest grade. It is true that a sample was sent to the Imperial Institute for analysis and report, but it was sent by the Administration and not by the holders of the concession, and only when the state of the industry had become seriously affected. The salt “pans,” in places mere holes in the ground, are dirty, not enough care has been taken to ensure a bed free from impurities, or to ensure protection of the pans from surface drainage. No attempt has been made on the part of the owners or management of the concession to acquire a knowledge of the working of successful pans elsewhere, or if it was possessed, no effort has been made to apply it.

In short, from the very beginning, the management has been extremely inefficient, and its attitude has apparently been that, so long as sufficient of the product could be sold to give a profit without incurring any expenditure except for labor, only so long should the industry be carried on, and the article sold should only be that which has been produced from the beginning.

The result has been that, when salt pans formed by the French at Djibouti and properly chosen and arranged began to produce salt that was of superior quality, the demand for Zeyla salt immediately fell away and has now become very small. Doubtless the construction of the railway from Djibouti into Abyssinia has caused some of the loss of trade, but this amount is small in comparison with that brought about by the inferior quality of the product.

The writer, in the course of a journey from Djibouti to Zeyla and of his stay in Zeyla, was able to make a brief examination of the salt-pan area, and from this examination and from information obtained from the District Commissioner, it would appear that there is, under certain conditions, a reasonable prospect of the revival of the industry.

To begin with, the salt capable of being produced is of high quality. Samples of the crude material analyzed at the Imperial Institute gave these results:

This analysis shows that even without purifying the salt compares very favorably with ordinary table salt.

By the simple method, moreover, of making a saturated solution, allowing the insoluble matter to settle and decanting off the clear brine into evaporation and crystallization tanks, the material can be purified to give the following composition:

From this analysis, it is clear that salt can easily be obtained from the pans equal to any on the market.

Again, the area suitable for salt production is of considerable size. It extends from Warabod, about eight miles south of Zeyla, to El Ghori, about twenty miles west of Zeyla, and comprises the “pans” of Abdi Kalil, Surir, Dawanboth and Laheiloh.

Moreover, it is well-known that Somalis, accustomed always to the use of camels, prefer this form of transport to any other, and it is, therefore, probable that provided the article is equal to any sold, the competition of the railway as regards transport to the interior will not prove as successful as it is at present when only an inferior article is being carried from Zeyla.

Further, with a high-grade article, and cheap transport facilities from Zeyla, there is no reason why the former overseas trade in salt from this port should not be revived. Some effort will, of course, be required, but efficient management of the industry should provide it.

To rehabilitate the industry, however, several conditions affecting the product must be observed. These include:

(1) Efficient management. The manager should have not only business ability but a knowledge of modern methods and requirements.

(2) Proper salt pans should be made to replace the crude native “pans” at present in use. Care should be taken that the bed of the pans should be clean and kept clean, and that surface drainage is prevented from flowing into the pans. There must be no direct communication of the pans with the sea except by canals, by which alone the sea water is introduced.

(3) Methods of producing salt from brine pans in places where the industry is a commercial success should be known or studied and, so far as practicable, be introduced.

(4) A cheap method of refining the crude salt, and not only of getting rid of the impurities but of producing the required grain, should be introduced. One has already been set out in a report by the Imperial Institute.

Though, up to the present, salt has been won from pans only round Zeyla, there appears to be a favorable outlook for its production in a similar manner immediately to the south and to the south-east of Karam, some 50 miles east of Berbera. South of this coastal police-post, there is the necessary flat, low-lying ground to which the sea-water could be easily admitted by canals, and which would form a clean bed that is unlikely to be contaminated by drainage. The only serious drawback to the locality may be that, owing to the sandy nature of the soil, there may be excessive loss of water before evaporation.

South-east of Karam, however, there are wide stretches of plain that would provide clean beds for the pans, with a firm soil through which percolation would be very slow, into which sea-water could be introduced without difficulty by canals, and which altogether appear very suitable. The salt, however, would have to be shipped only in small dhows from Karam, which is an open roadstead, or would require to be transported by camels to Berbera. Should it be found possible to exploit the coal south of Ankor, the same means of transport adopted for the latter could be used for the salt.

The salt deposit just south of Hais occurs in small caves just below the surface of the Eocene limestone cap on a small ridge which has been faulted down from the main limestone scarp further to the south. The mineral occurs in small lumps of a sugary appearance and consistency. An analysis of a sample at the Imperial Institute gave the following results:

The deposit is small, occurs sporadically, and can therefore only be of value for local use as a stock lick, for which purpose it is being employed at the present time.

The deposits at Dagah Der and Darraboh Hill are known only from the statement of Mr. H. M. O’Byrne, Collector of Customs at Berbera. Though the present writer had with him two native guides familiar with the whole district south of Karam, he was unable to find either of these two hills or any salt deposit in the district. This is explainable by the fact that hills throughout Somaliland, known to one section of a tribe by one name, are known to another section only by a totally different name, and by the probability that the salt specimens were collected for Mr. O’Byrne by Somali villagers. Had time permitted, an effort would have been made to discover the original collector of the specimens, as usually only by this means can deposits be found without considerable delay.

The notes accompanying the specimens were:

1. “Pieces chipped from block in Dagah Der Hill through exposed orifice.”
2. “Piece chipped from block in Darraboh Hill through exposed orifice.”

Both samples were fragments of compact crystalline salt. Analyses of them made at the Imperial Institute gave:

Though the analyses show that the salt is fairly pure for naturally occurring material, in view of the fact that, the mineral would have to be transported a considerable distance before purification, that, to judge from the notes, the deposits occur in caves and are probably of limited extent, and that very large quantities can be produced at a low cost at the sea-coast at Zeyla and probably at Karam, it is unlikely that either deposit would pay to work.

It has been alleged that the occurrence of these deposits may point to the possible presence of petroleum in the neighborhood, but a geological examination of the country lying south of Karam as far as Las Dureh proves it to consist largely of eroded fault blocks of Dubar Sandstone capped in some instances by Eocene limestone, or, as at Ambal, of Jurassic limestone blocks capped by Dubar Sandstone, and, except for the pseudodome at Ambal, destitute of any structure that could act as an oil reservoir.

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