20 THE CUBA REVIEW 



concordance in altitude. They stand from 500 to 1,200 feet above sea level, and roost 

 of them are at altitudes near 600 to 700 feet, suggesting a relation between the 

 deposition of the manganese and a certain stage in the physiographic development 

 of the region. Most of the manganese ore deposits are above drainage level on the 

 slopes of hills of moderate height, the maximum relief in the immediate vicinity 

 of the deposits seldom exceeding 500 feet. 



TYPES OF MANGANESE ORE DEPOSITS 



The deposits of manganese ore examined in Cuba are rather diverse but may be 

 grouped into three general physical types — bedded deposits, irregular masses asso- 

 ciated with siliceous rock or "jasper," and deposits in residual clay. The bedded 

 deposits comprise several varieties, one of the most common consisting of poorly con- 

 solidated beds of sandy chloritic material cemented with manganese oxides that fill 

 inequalities in the surface of hard rocks. Other bedded deposits clearly replace lime- 

 stone, shale, conglomerate, or other rocks, and tabular masses of ore are interbedded 

 with strata of nearly horizontal limestone. 



The ore consists largely of pyrolusite, but many deposits contain psilomelane, 

 manganite, and wad, or mixtures of all these minerals. The richness of the deposits 

 varies considerably. Most of the richest masses are associated with the "jasper," 

 but masses that have replaced limestone thoroughly are also rich. 



DISTRICT NEAR SANTIAGO 



The deposits of manganese ore examined in the Santiago district comprise the 

 Ponupo group, the Ysobelita, Botsford, Boston, Pilar, Dolores, Laura, San Andreas, 

 Cauto (Abundancia), Llave and Gloria mines, and the Caridad and Valle prospects. 

 All these properties except the two prospects were producing ore. A few small pro- 

 ducing mines in the district were not visited. The Ponupo, Ysobelita and Boston 

 mines were opened many years ago and have produced a large quantity of ore. 

 The Ponupo and Ysobelita are still relatively large producers, though the grade of 

 ore is not now so high as that of the ore shipped in the earlier days. 



The three types of manganese ore deposits and their several subordinate va- 

 rieties are well displayed in this district, especially at the Ponupo group of mines. 

 Here, at the Generala openings, bedded material fills solution cavities and crevices 

 in limestone, in some places to great depths. At the Sultana opening manganese 

 oxides have replaced shaly and sandy conglomeratic beds that dip N. 10° E. at an 

 angle of about 18°. This deposit is apparently a lens, having a maximum thickness 

 of about 20 feet, the lower half of which is richer in manganese than the upper 

 half. At the Juanita opening manganese has in spots replaced limestone. At the 

 Balkana opening the ore is found in siliceous rock, or "jasper," that apparently 

 fills a large fissure in limestone. At the Vincidora openings ore is associated with 

 "jasper" and also occurs in lumps in residual clay in pockets between boulders of 

 "jasper." 



The Ponupo mine is directly connected with the Cuba Railroad at La Maya by 

 a branch about two miles long, and a narrow-gauge track from Oristo, on the Cuba 

 Railroad, to the Ysobelita mine, a distance of about three miles, is reported to be 

 practically completed. Extensions of this line to the Boston and Pilar mines could 

 be made without great additional outlay. The Dolores and Laura mines are near 

 the Guantanamo & Western Railroad, near Sabanilla station, and the Cauto mine is 

 adjacent to the Cuba Railroad at Manganeso station. The other mines are one to 

 eight miles from railroad, to which the ore is hauled mainly by oxcarts. In the rainy 

 season the roads are impassable, and even in the dry season they include many dif- 

 ficult places, so that the quantity of ore hauled is less than can be mined. 



