General History of El Oro
Mining
| 1529 | First records of mining was by Spanish in the Borda Coronas Area |
| 1700s | Cornish Tin miners arrive in El Oro and restart mining of the Spanish discoveries |
| 1880s - 1929 | El Oro Bonanza Mining Period: El Oro Mining, Esperanza Mining, Mexican Mining discover and mine the San Rafael Vein & others |
|
1900 |
Dos Estrellas Mining Co drives adit and discovers Veta Verde |
|
1929 |
San Rafael mine floods and production stopped |
| 1929 - 1938 | Dos Estrellas Mining Co. continues to mine Veta Verde, bankrupt in 1938 following a tailings dam slide |
| 1938 - 1959 | Mexican government hands over the district to the Workers Cooperative. Mining of backfill and pillars continued until 1959 on an ad hoc basis with processing plant located in Borda /Coronas area. Production appears to be minimal but no records exist |
Exploration
| 1969 - 1971 | More Mines Limited; Drilling Total: 2 holes, 513m - no results kept |
| 1983 - 1990 | Luismin drilled the surrounding areas for new veins 33 drill holes / 7064m completed with the Buen Despacho, Zona Oriente. Cortaduras, San Francisco de Reyes, Pomoca targets tested |
| 1993 | Hillsborough - San Rafael remnant resource definition drilling Total of 12 drill holes / 3008m |
| 1996 - 1997 | Teck - IP Geophysical Survey and Geochemical Surface Sampling Program - Veta San Rafael & Verde, Zona Oriente Drilling of IP targets mostly identified dykes not veins: 13 drill holes, 3069 m - Veta Verde, Zona Oriente, Cortaduras targets tested |
| 2003 - 2004 | Placer Dome - San Rafael Vein Drilling Total: 11 drill holes, 5021m Geochemical Surface Sampling Program Oriente |
| 2007 | Minera CCM S.A. de C.V. (Xali) Geophysical Program: Resistivity NASTM Regional Geochemical sampling Drilled 4096m in 11 holes underneath old mine workings in four veins: 8 holes hit targets and 7 mineralized structures intersected |
San Rafael Vein
Historic Production of 5 million ounces of gold equivalent
- Average grades: 10-12 g/t gold & 120-160 g/t silver
- Average Widths: 3 to 10 metres
- Bonanza grades: up to 50 g/t gold & 500 g/t silver
- Widths: up to 70 metres in places
Continuous vein mineralization over 2.4 kilometres of strike length
Mined from 1896 to 1929 by 3 companies concurrently in 3 contiguous sections:
- Mexico Mine (North)
- Esperanza Mine (Central)
- South Mine (South)
Mining closed down in 1929 due to:
- Labour difficulties
- Costs vs low price of gold
- Pumping technology
Flooding in one section of the San Rafael vein in 1929 resulted in the other two sections flooding and work ceasing abruptly and unexpectedly
The Full Potential of the San Rafael Vein has Never Been Properly Investigated.
*Estimate by Luismin, Historic & non NI 43-101 compliant