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McLemore V.T.,New Mexico Institute of Mining and Technology | Dunbar N.,New Mexico Institute of Mining and Technology | Tachie-Menson S.,Freeport McMoRan | Donahue K.,Telesto Solutions Inc.
Tailings and Mine Waste'10 - Proceedings of the 14th International Conference on Tailings and Mine Waste

The Goathill North (GHN) rock pile was constructed in 1964-74 and re-graded in 2004-05. GHN samples were subjected to static, petrographic, and chemical tests to characterize acidity and future acid-producing potential (AP). Samples that have higher concentrations of pyrite are more likely to have a higher AP. Static tests indicated that, although the rock-pile material contains acid consuming minerals, acid generation has occurred. Samples with rhyolite rock fragments have lowerNP (neutralization potential) then samples with andesite rock fragments. Samples with rhyolite rock fragments had undergone hydrothermal quartz-sericite-pyrite (QSP) alteration, whereas samples with andesite rock fragments were propylitically altered; these hydrothermal alterations occurred after the molybdenum mineralization, but prior to mining. No single component controls the ABA (acid-base accounting) and NAG (net acid generation) tests. This lack of correlation between ABA and NAG tests, mineralogy, and chemistry is a result of 1) weathering reactions in the soil matrix producing precipitation of coatings surrounding the rock fragments and preventing further weathering of the rock fragments, especially around pyrite crystals, 2) a lack of the water available that is required for weathering in the 25-40 years since the formation of GHN rock pile, 3) non-uniform weathering of pyrite within the rock pile due to heterogeneous air flow, and 4) little or no weathering of the rock fragments. Also, the AP capacity of the rock-pile is determined by the combination of K-feldspar, calcite, smectite, illite, and pyrite, which are controlled in part by the lithology, pre-mining hydrothermal alteration, and post-mining weathering. The effects of pre-mining hydrothermal alteration and post-mining weathering both affect the static tests, emphasizing the need to perform detailed petrographic and mineralogic investigations along with the static tests to determine the AP of any mine waste material. © 2011 Taylor & Francis Group, London. Source

Dessureault S.,University of Arizona | Benito R.O.,Freeport McMoRan
Transactions of the Institutions of Mining and Metallurgy, Section A: Mining Technology

This paper discusses the first steps in a process which combines historical production and cost data with long term mine schedules to develop an equipment replacement analysis tool. The focus is on the enabling technology of data mining, used to define key physical and economic parameters for the proposed model, as well as model the relationships between key variables. This research considers two types of physical parameters for equipment replacement analysis purposes: operational and maintenance parameters. Activity based costing, an evolutionary extension of the two stage procedure in modern cost accounting, is applied in this research to determine full operating and maintenance costs by machine. This technique is mainly used to trace costs such as general expenses (e.g. overhead costs) from activities to products based on a representative cost driver. © 2012 Institute of Materials, Minerals and Mining. Source

Everly C.R.,Freeport McMoRan
2015 SME Annual Conference and Expo and CMA 117th National Western Mining Conference - Mining: Navigating the Global Waters

The purpose of this paper is to review the most effective methods of reducing chloride transfer and chloride removal in the solution extraction and electrowinning (SX/EW) process. Elevated chlorides in electrolyte have various negative effects including a reduction in current efficiency, increased handling costs at rod plants and smelters, increased anode corrosion, cobalt losses due to increased electrolyte bleed, degradation of HDPE piping, and increased corrosion in the SX/EW plants. Historical controls that Sierrita has used to control chloride transfer, in order of effectiveness, have been chloride gasification at the EW that is directly correlated to amperage and chloride concentration in electrolyte, wash stage bleed and efficiency, width and velocity of aqueous bands, and electrolyte bleeds. Maintaining high bleed rates and high amperage settings has been a challenge with decreasing pregnant leach solution (PLS) grades, so keeping chlorides out of the electrolyte has become imperative. The effectiveness of reducing aqueous entrainment, optimizing wash stage efficiencies, and improving organic quality to reduce the transfer of chlorides to the electrolyte are illustrated in this study. Copyright © 2015 by SME. Source

Liu C.M.,Freeport McMoRan
2015 SME Annual Conference and Expo and CMA 117th National Western Mining Conference - Mining: Navigating the Global Waters

The Freeport-McMoRan Sierrita Crystal Plant produces Copper (II) Sulfate Pentahydrate (CuSO4·5H2O) through a series of cooling crystallizers. In this process, high supersaturation and unwanted spontaneous nucleation promote fine crystals. Seeding through recycled crystal classification can manipulate the crystal size distribution (CSD) for larger crystals. Proper selection of the crystallizer for seeding can prevent spontaneous nucleation and promote final crystal size. This study shows when seeding temperature is closer to the crystallizer temperature, suspension densities in the crystallizers are promoted and overall CSD shifts to a larger size of crystals. Copyright © 2015 by SME. Source

Crawled News Article
Site: http://www.ogj.com

Anadarko Petroleum Corp., Houston, has agreed to acquire the deepwater Gulf of Mexico assets belonging to Freeport McMoRan Oil & Gas (FMOG), a subsidiary of Phoenix-based mining firm Freeport-McMoRan Inc., for $2 billion.

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