218 F. Dixey — Later it ization in Sierra Leone. 



The grade and structure of the ores vary considerably. The 

 common variety is pisolitic ; the cores of the pisoliths are black and 

 deep red, the enclosing part red, and the interstices between the 

 pisoliths are more or less filled with limonite. Another variety 

 is finely mottled in purple, red, and yellow, and shows only a slight 

 development of the pisolitic structure. The richest ores are made 

 up of nodules or small masses of almost unaltered titaniferous 

 magnetite, whereas the poorest ores are concretionary and contain 

 only a low percentage of iron, chiefly in the form of thin limonitic 

 coatings to the concretions. 



A fragment of ore exposed on the surface of the ground weathers 

 into a rounded nodule, and assumes a smooth polished ferruginous 

 skin of a dark-brown colour. 



The Devil Hole ores form a belt 400 to 500 yards wide, running 

 parallel with the foot of the hills ; the belt has been traced for three 

 miles, and probably extends over a much greater distance. Several 

 small shafts and a trench 15 yards long were excavated in the deposit 

 with the help of explosives ; the sections showed soil and subsoil 

 up to 15 inches in thickness, passing downw^ards into a rubble 

 containing large and small coarsely porous lumps. Underlying the 

 rubble were large masses of a comj^act ore, which locally assumed 

 an irregular platy structure. The ore was proved to a depth of 

 8 feet, and it probably continued to a much greater depth ; there are 

 thus well over 3,000,000 tons of ore indicated in this deposit. The 

 deposit runs parallel with the Sierra Leone Government Railway, 

 and is practically adjacent to it ; moreover, since it is separated from 

 the mouth of the Bunce River only by a narrow strip of the plain, 

 about a quarter of a mile wide, the ore could be shipped directly 

 at very little cost. 



Mr. Gr. F. Scott Elliott ' gives the following analysis of a sample 

 of the ore from this district (" the hills behind Sierra Leone ") : — ■ 



Other analyses^ of representative samples show that the amount 

 of titanium they contain varies from 3 to 20 per cent, and since, 

 under present conditions, steel cannot be made at a profit from 



' Col. Pvcp. Misc., No. 3 (Sierra Leone), 1S93, p. fi. 



" Kindly made for the Geological Survey by the Wigan Coal and Iron 

 Company, Ltd. 



