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Englewood, CO, United States

Sun C.,Newmont Mining Corporation
Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics | Year: 2012

The Leeville underground mine has been in operation since 2006 and currently produces 3176 tons (3,500 short tons) of ore per day with an average gold grade of 10 g/ton (0.32 opt). The mine has a large horizontal extent of 762m (2,500 feet) by 152m (500 feet) and a vertical extent of 6.1 to 61m (20 to 200 feet). Based on the characteristics of the ore bodies, the deposits are divided into several mining zones. The geotechnical properties of mining zones are also different from one zone to another. The typical ground condition at Leeville is poor to very poor. So, an appropriate ground support system is key for the successful production at the Leeville underground mine. Based on the available geotechnical data, the empirical and numerical methods are used to construct the ground support system at the Leeville underground mine. The main ground support system includes in the following. Geotechnical data collections, core logging, site investigation and extra geotechnical drills. Based on the analysis of geotechnical information, appropriate stiffness of support system is selected. Flexible and active support system fit the ground condition at the Leeville underground mine. Rock bolts selection, using characteristics of the ground deformation and anchorage capacity of rock bolts to select the suitable rock bolt in the ground support system. Determination of the length and the pattern of the rock bolts, using empirical method determine the length and the pattern of rock bolt in ground support system. Construct the ground support standard, based on the variety of ground condition at the different mining zones and service time of the drifts, the ground support standard is established. Quality control, to secure the ground support system being workable, the quality control is conducted to check anchorage of the rock bolts, strength of the shotcrete, and backfill. The ground support system has been constructed and applied at Leeville underground mine for four years, with good achieved, although the system is still being improved. © 2012 Taylor & Francis Group, London.

Dunne R.,Newmont Mining Corporation
Water in Mineral Processing - Proceedings of the 1st International Symposium | Year: 2012

The demand for water is driven primarily by population and concomitant economic growth. Water requirements are predicted to grow considerably in the next decades while supplies will remain relatively constant or decline due to over pumping of aquifers, changing weather patterns and increased water pollution and contamination. Mining activities are often located in remote, arid environments, with limited access to high-quality water. The water used in mining operations comes from a variety of sources and the sources and quality of the water varies from operation to operation. Mining impacts on water quantity and quality are among the most contentious aspects of mining development. The main problem for the mining industry is to generate confidence in developing a responsible, sustainable and transparent water management strategy that is recognized as such by all stakeholders. This paper provides an overview of water in the wider global arena and compares this to how the mining industry has dealt with water stewardship over the last couple of decades.

Dietrich M.,Newmont Mining Corporation
Mineral Processing and Extractive Metallurgy: 100 Years of Innovation | Year: 2014

Innovation is the development of new solutions to meet the demands of the times. In the mining industry innovations have been driven by government regulatory changes, economic influences and the demand for metallurgical process improvement. Analytical chemistry is the force behind metallurgical advancement and discovery. Measurement is the key to understanding what you have achieved. The analysis of metals was among the earliest applications of analytical chemistry. While fire assay for analysis of precious metals has changed very little in the past 500 years, the majority of analytical equipment in the laboratory has changed dramatically in the past 60 years. As a result assays and analyses which took days to complete, changed to hours, hours improved to minutes, and minutes to seconds in some cases. These improvements came through the discovery and optimization of electronic instrumentation; particularly flame Atomic Absorption Spectrometer, Inductively Coupled Plasma-Optical Emission Spectrometer, Inductively Coupled Plasma-Mass Spectrometer, X-Ray Fluorescence and quick combustion gas analyzers.

Eastoe C.J.,University of Arizona | Rodney R.,Newmont Mining Corporation
Water (Switzerland) | Year: 2014

High-elevation groundwater sampled in 2003 in the Sacramento Mountains defines a line resembling an evaporation trend in δD-δ18O space. The trend results from recharge of winter precipitation into fractured limestone, with evaporation prior to recharge in broad mountain valleys. The same trend occurs in basin groundwater east and west of the range, indicating the high Sacramento Mountains as the principal regional water source, either direct from the limestone aquifers or from mountain-derived surface water. Tritium and carbon-14 indicate bulk residence times of a few decades in the high Sacramento Mountains and at Alamogordo, and of thousands of years south of Alamogordo and in the artesian aquifer near Artesia. Stable O, H isotope data fail to demonstrate the presence of Sacramento Mountains water in a saline aquifer of the Hueco Bolson (Texas). © 2014 by the authors.

Pryne D.,Fugro | Van Arsdale R.,University of Memphis | Csontos R.,Newmont Mining Corporation | Woolery E.,University of Kentucky
Bulletin of the Seismological Society of America | Year: 2013

Analysis of electric and geologic logs of 517 shallow wells (91 m, 300 ft deep) in southeastern Missouri has revealed a subsurface structural high (herein called the Charleston Uplift) trending N46°E from near New Madrid, Missouri, to Cairo, Illinois, that juxtaposes Paleocene Flour Island Formation against Eocene Claiborne Group. The Charleston Uplift is 30 km (19 miles) long, 7.2 km (4.5 miles) wide, and has a relief of 36 m (120 ft) at the unconformity surface between the Paleogene and Quaternary sections. Two seismic-reflection soundings, one conducted north of the uplift, and the second conducted within the uplift indicate 60 m (198 ft) of apparent structural relief on the underlying top of the Paleozoic, 47 m (155 ft) on the top of the Late Cretaceous, and 19 m (63 ft) on a Tertiary reflector. The Charleston Uplift is interpreted to be the northeastern extension of the New Madrid North fault of the New Madrid seismic zone and locally the western margin fault zone of the Reelfoot rift. Although no surface faulting has been mapped along the Charleston Uplift, the uplift appears to have influenced the Holocene course of the Mississippi River and displaced the Paleocene/Quaternary unconformity, thus indicating Quaternary displacement of the Charleston Uplift across southeastern Missouri, which may continue beneath the Ohio River valley into adjacent Illinois and Kentucky. Thus, the Charleston Uplift strongly suggests Quaternary structural continuity between the Reelfoot rift and Rough Creek graben of Kentucky. Although currently seismically quiet, the 12 February 2012 M 3.9 earthquake and probably the 31 October 1895 ~M 6.6 Charleston earthquake occurred on this structure, thereby illustrating the seismic potential of this structure and extending the New Madrid North fault system at least 30 km (19 miles).

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