Tin Deposits of Durango Mexico GEOLOGICAL SURVEY BULLETIN 962-D Tin Deposits of Durango Mexico By WARD C. SMITH, KENNETH SEGERSTROM, and REINALDO GUIZA, JR. GEOLOGICAL SURVEY BULLETIN 962-D Prepared in cooperation with the Universi- dad National Autonbma de Mexico, Ins- tituto de Geologia, and the Comite Directivo para la Investigation de los Recursos Mine- rales de Mexico under the auspices of the Interdepartmental Committee on Scientific and Cultural Cooperation, Department of State UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1950 UNITED STATES DEPARTMENT OF THE INTERIOR Oscar L. Chapman, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. CONTENTS Page Abstract___ _____________________________________________________ 155 Introduction. _____________________________________________________ 155 Field work__________________________________________________ 156 Acknowledgments _____________________________________________ 156 Geologic features._________________________________________________ 157 Mining and concentrating-_________________________________________ 158 Sampling and assaying___-______________-__________________-___-___ 160 Production statistics and estimates. _________________________________ 163 Districts and mines examined___:____________________________________ 165 Deposits in the Cerro de los Remedies.__________________________ 165 Character of the veins____________________________________ 166 Exploratory work, 1943-44______________________ 167 Size and grade of ore bodies_______________________________ 167 La Vanguardia mine, Tiro Norte workings____________________ 168 La Vanguardia mine, Tiro Sur workings_______.____________._ 169 Remedies mine, Tiro Tomds workings________________________ 169 Tiro Bolivar workings____________________________________ 170 Socav6n del Polvorfn and Socav6n Nuevo____________________ 171 Deposits of the Am<§riea-Sapiorfs district.________________________ 171 General features____--__-_-----____--____________________ 171 Lodes_ _______________________________________________ 171 Plaeers_______________________________________________ 173 Mines near America.______________________________________ 174 Grant___________________________________ 174 Las Barrocitas________________________________________ 176 Orozeo_ ______________________________________________ 177 Obsidiana mine of Herman West _______________________ 179 Candelaria____ ________________________________________ 179 Jaltomates____ _ _______________________________________ 180 Las Carpas-__________________________________________ 181 San Miguel-----_--------------------------------_____ 182 La Fierrosa, La Lentejuela, and La Alta________________ 183 Veintinueve de Junio_________________________________ 184 Mines near El Pinto and El Pipidn__________________________ 185 Deposits near Ochoa__---_--_--___--____----____-______________ 187 Los Arrieros______________________________________________ 188 Cerro Grande_----------------_-----------_-----__-_______ 188 Other mines and prospeets__________________________________ 189 Deposits near Canatldn________________________________________ 190 Deposits southeast of Rio Verde-___--__-__-_-_---_--____________ 193 ElDiablo___--__----___-__--_--___------------___.______ 194 La Marta and other mines__________________________________ 195 Deposits in southern and western Durango_______________________ 197 Economic possibilities._____________________________________ 197 Geography______________________________________________ 197 Location of deposits and routes of access _____________________ 198 Metric equivalents.________________________________________________ 202 Index_______________.________________________ 203 m ILLUSTRATIONS PLATE 32. Index map of Durango, Mexico, showing geology and loca­ tion of tin-bearing areas_._____________-__-_-_-__-.__ In pocket 33. Geologic and claim map, Cerro de los Remedios, Du­ rango, Mexico____________________________________ In pocket 34. Map of mine workings, Cerro de los Remedios, Du­ rango, Mexico, showing geology and assay data._______ In pocket 35. Planimetrie map of the Ame'rica-Sapioris tin district, Du­ rango, Mexico_____________________________ ._.__.___ In pocket 36. Geologic map and section of the America tin district, Du­ rango, Mexico-_________________________________ In pocket 37. Geologic map and sections of the Grant mine, America tin district, Durango, Mexico.._____________________ In pocket 38. Geologic map and projections of Las Barroeitas mine, America tin district, Durango, Mexico_____________ In pocket 39. Geologic map and projections of the Orozco mine, America tin district, Durango, Mexico________________________ In pocket 40. Geologic map and projections of the Candelaria mine, America tin district, Durango, Mexico.________________ In pocket 41. Geologic maps and sections of the Jaltomates and Las Carpas mines, America tin district, Durango, Mexico___ In pocket 42. Plans and projections of the San Miguel and Veintinueve de Junio mines, America tin district, Durango, Mexico. _ In pocket 43. Geologic map of El Pinto-El Pipian area, Sapioris tin dis­ trict, Durango, Mexieo____________________________ In pocket 44. Sketch map of tin-bearing area near Ochoa, Durango, Mexico. In pocket 45. Plans and sections of the Cerro Grande and Los Arrieros tin mines near Ochoa, Durango, Mexico_______________ In pocket 46. Sketch map of tin-bearing area near Canatlan, Durango, Mexico________________-____-___--------___________ In pocket 47. Index map showing location of tin deposits in the Rio Verde district, Durango, Mexico______________. ____ In pocket 48. Plan and sections of El Diablo mine southeast of Rio Verde, Durango, Mexico.___________________________ In pocket 49. Plans and projections of La Providencia, La Argelia, and La Marta tin mines near Rio Verde, Durango, Mexico. _ In pocket TIN DEPOSITS OF DURANGO, MEXICO By WARD C. SMITH, KENNETH SEGERSTROM, and KEINAI/DO GUIZA, Jr. ABSTRACT This report summarizes the economic possibilities of the tin deposits of the Estado de Durango, Mexico. It describes in detail many deposits in the leading districts, which were examined in 1944, and briefly reviews some reports on undeveloped occurrences in the southern and western parts of the State. The general conclusion is that tin will continue to be produced by hand methods for many years, but probably at a decreasing rate, because the placer grounds which have always produced the greater part of the tin are faced with gradual exhaustion. Future production cannot be estimated closely be­ cause there is no complete record of past production which, however, has certainly averaged over 150 tons a year and perhaps over 300 tons. The most interesting activity in the tin districts of Durango during 1943 and 1944 consisted of attempts to mill the ores. A 100-ton mill built at Ochoa was shut down after a test run, but a 10-ton mill might be operated there intermittently. More development work is needed to insure an ore supply. Tin mills at Cerro de los Remedies and at Canatldn have little chance of suc­ cessful operation, for little ore has been developed at Cerro de los Remedies and almost none at Canatlan. In the America-Sapioris district and the area near Rio Verde many deposits have been opened up in small mines, but in neither place is there any single mine or group of mines with sufficient ore in sight to justify building a mill. The small size and uneven grade of the deposits in those areas makes hand mining and washing more suitable than mechanized methods. A concentrating plant, to be successful, would have to operate profitably on ores that contained 0.1 to 0.2 percent of tin, since that seems to be the general range in tin content of the mineralized fault breccias that form the most extensive bedrock deposits. INTRODUCTION This report, dealing with the economic value of the tin deposits of the Estado de Durango, Mexico, is based upon examination of the outstanding districts in the State during the period June to Novem­ ber 1944. The time was opportune for such an economic review, because four plants for concentrating tin ore were built in the State late in 1943 and early in 1944, marking the first strong effort in 50 years to introduce large-scale machine methods in a region where mining and milling has been carried on almost entirely by simple hand methods. The results of the milling ventures and of the writers' examination of the deposits all point to the same conclusion, namely, that the 155 156 GEOLOGIC INVESTIGATIONS IN) THE AMERICAN REPUBLICS, 1949 bodies of tin ore are too small and pockety and too low in average grade for profitable mining and milling by large-scale methods at the present price of tin. By November 1944, all the new mills had shut down. One ran intermittently for several months, two made only short trial runs, and the fourth was never completed. This report contains only a very condensed account of the general geology and mineralogy of the tin deposits. The report on the tin deposits of Mexico made by Foshag and Fries in 1941 x is concise yet accurate, and substantially complete as to all major features. The present report gives many additional details regarding certain in­ dividual mines or districts, but it makes no significant addition to the general scientific deductions made by those authors, and does not modify their economic conclusions. The report deals chiefly with the vein deposits and mentions the placers