South Eureka Property, Eureka Mining District, Eureka County, Nevada, USAi

Regional Level Types
South Eureka Property	Property
Eureka Mining District	Mining District
Eureka County	County
Nevada	State
USA	Country

Structure: The deposit is situated at the southern end of Dunderberg-Windfall belt. northeast-striking fissures

Alteration: Dolomite has been "sanded" due to intergranular corrosion.

Commodity: Ore Materials: native gold, cerussite, smithsonite Gangue Materials: scorodite, limonite, quartz, calcite, dolomite

Deposit: Gold occurs as disseminated, low-grade ore in Hamburg Dolomite, forming a number of shoots controlled by intersection of NE-striking fissures or faults with the Hamburg Dolomite. Ore occurs primarily in the dolomite, adjacent to the faulted contact with a rhyodacite intrusive body. Mineralization here is unique from that in the rest of district in the paucity of lead and silver. The Rustler deposit, an extension of the Windfall deposit 0.5 mile south was found and put into production. Much of the Rustler ore occurs in zones that have been thoroughly silicified and somewhat brecciated. Drilling has shown that ore grade material extends from the south end of the Windfall pit to the north end of the Rustler pit. The Windfall ore bodies differ markedly from the other mineralized bodies in the district in that they are low-grade gold ore shoots with indistinct assay walls. The shoots exhibited marked structural and stratigraphic control , localized by the intersection of NE-striking fissures or faults with the Hamburg Dolomite. Staccato completed a Phase One 3-hole core drill program on the Lookout portion of the property in November 2005. Each of the three holes intercepted high-grade gold over significant interval lengths. A nine-hole follow up core drill program was underway in 2006. The nine-hole drill program will complete each hole to a depth of at least 300 meters (1,000 feet), and is designed to follow-up the November, 2005 drill program. Using the newly identified mineral model, the nine new holes are designed to extend the high-grade breccia-hosted mineralization along strike as well as laterally to the feeder structures. The structures are part of the Ratto Ridge Fault system which has been traced for a length of more than 4 kilometers (2.5 miles) by previous drilling, mapping and sampling. The Ratto Ridge Fault system represents a small portion of Staccato's 100% owned South Eureka property, which comprises an area of over 17,600 acres (27 square miles).

Deposit type: Sediment-hosted Au

Development: Mineralization was discovered in the Windfall area in1904, and an underground mine and cyanide vat leach recovery facility produced and treated 65,132 tons of ore valued at $349,428 from 1908 to 1916. Production continued intermittently until about 1940. The property was acquired by Idaho Mining Corp. in 1968, which developed and tested it from 1972 to1974, built a plant in 1975 and began production in 1976, mining the same ore body via open pit methods. Between 1975 and 1978 the Windfall Pit, and associated cyanide heap-leach piles, waste dumps, mill process building, office and laboratory were constructed. Because the ore body contains anomalous amounts of mercury, a retort was constructed to recover mercury as a by-product. The Windfall Venture group conducted the bulk of exploration during the period 1970-1980 in an attempt to expand on their Windfall Mine reserves. Work on the immediate Hoosac property consisted of soil and rock chip sampling, limited geologic mapping, and drilling 63 shallow rotary drill holes. Six of the holes intersected shallow mineralization in excess of 700 ppb Au. Amselco Exploration leased the claims in the mid-1980s and drilled eight holes on the east side of the property Windfall Ventures continued mining until about 1989, employing 35-46 workers. The last operator of the site was Norse Windfall Mines, Inc. in 1990, after which the site was abandoned with little or no reclamation. In 1994 and 1995, the Nevada Division of Environmental Protection and subcontractors conducted several inspections and evaluations of the Windfall Mine site and noted that unmaintained process components and materials left on the property had the potential to degrade waters which constituted part of the water supply for the town of Eureka. In 2001, two underground storage tanks and over 300 mostly empty chemical drums were removedfrom the site. Periodic sampling and monitoring of the water in existing wells was begun, and two monitoring wells were drilled, mercury and arsenic contaminated soil around the old mercury retort and mill building were removed. Tenneco Minerals drilled the property in 1989-1991. Pathfinder Exploration explored the property in 1992 and 1993. Activities by Pathfinder consisted of collection of BLEG samples, geologic mapping, collection of rock and soil samples, ground magnetics/VLF surveys, and completion of 18 reverse circulation holes for a total of 3,284 m drilled. Six of the holes intercepted thick intervals of anomalous gold mineralization ranging upwards of 24 m of 822 ppb Au. The property was joint ventured to Cambior Exploration in 1994. Cambior mapped approximately 2,071 ha, collected rock chip and soil samples, and completed 26 reverse circulation drill holes for a total of 5848 m drilled. Intercepts in the 1995 program consisted of 13.7 m of 445 ppb Au, 7.6 m of 692 ppb Au, and 51.8 m of 450 ppb Au. The fourteen-hole 1996 drilling program encountered widespread alteration and anomalous trace element geochemistry, but little gold (10.6 m of 0.116 g/t Au). Detailed mapping and sampling identified ore controlling structures and Archimedes-type host rocks on the west side of Hoosac Mountain as drill targets. By 2006, Staccato Gold Resources, Ltd. had consolidated several earlier mined adjacent producing properties over 17,600 acres (27 square miles) into their "South Eureka property" which includes the Windfall Mine, the Rustler pit, North and South Paroni pits and the Lookout Pit as well as five claim blocks: Lookout Mountain, Hiero/Syracuse, Windfall Patents, South Ratto and Hoosac, as well as a separate bloc at New York Canyon. Staccato increased its gold resource for the combined property to 545,000 ozs Au measured and indicated, and 336,000 ozs Au inferred, including a coherent high-grade deposit of more than 200,000 ozs, averaging .24 ozs per ton.

Geology: Gold occurs as disseminated low-grade ore in Hamburg Dolomite. The ore forms a number of shoots, that were controlled by the intersection of northeast striking fissures on faults w/the upper Hamburg Dolomite. The mineralization here is unique in regards to the rest of the district, by the absence of the lead and silver

Ore(s): Fractured permeable zones and capping shale have localized ore formation, as well as the intersection of northeast-striking fissures and faults with the upper Hamburg Dolomite.

References

Other Databases

Link to USGS MRDS:	10310482