Semantic Scholar extracted view of "Pulsed Neutron Porosity Logging Using Epithermal Neutron Lifetime" by L. S. Allen et al. Skip to search form Skip to ..., title={Pulsed Neutron Porosity Logging Using Epithermal Neutron Lifetime}, author={Linus S. Allen and William R. Mills and David C. Stromswold}, journal={The Log Analyst}, year={1989 ...

Low sulphidation epithermal Au-Ag deposits are distinguished from high sulphidation deposits primarily by the different sulphide mineralogy (pyrite, sphalerite, galena, …

An Exploration Framework for Porphyry to Epithermal Transitions in the Toodoggone Mineral District (94E) Lead ... The Toodoggone mineral district also hosts the idled Shasta epithermal gold-silver mine and Baker mill. Both porphyry copper and epithermal silver and gold deposit types found in the Toodoggone mineral district are possibly part of ...

A logging tool for in-situ measurement of earth formation porosity using epithermal neutron lifetime has been constructed and tested. A 14-MeV neutron generator in the tool emits pulses of neutrons and a Gd-covered /sup 3/He counter detects neutrons returning from the formation as a function of time following the emission pulse. Counts are accumulated in …

Greg Corbett, Consultant Geologist AIG Presidential Lecture 2001-2002. Click here to download paper as PDF . ABSTRACT. Epithermal gold (± Cu & Ag) deposits form at shallower crustal levels than porphyry Cu-Au systems, and are primarily distinguished as low and high sulphidation using criteria of varying gangue and ore mineralogy, deposited …

 — At least 43 epithermal Au, Au-Cu and Ag-Pb-Zn deposits occur in South China Block. • Mineralization mainly occurred in two periods of 180–130 Ma and 120–90 Ma.. Ore systems aged 180–130 Ma were formed in syn- to post-collision tectonic setting.. The deposits aged 120–90 Ma resulted from the westward subduction of Pacific plate.. …

Disadvantages zMay cause fast fission interference with Thorium-232 zHighly active Cadmium which gives off gamma rays. zNeeds to be near the core for epithermal flux, Cd lower the neutron flux which nuclear reactor operators may not want zCd can melt zCd burnup, becomes less effective over long periods of use zTime needed to take off Cd foil …

 — This patent describes a pulsed neutron porosity logging method. It comprises: repetitively irradiating a subsurface formation with bursts of fast neutrons, measuring the die-away rate of epithermal neutrons during a die-away spectrum for the epithermal neutrons within the irradiated subsurface formation substantially between …

 — With the aim of irradiating small biological samples, the epithermal beam was moderated by a polyethylene disk 2 cm thick, with a diameter of 13 cm.Some samples were fixed to this disk that was placed against the collimator mouth, other were settled in the polyethylene cylindrical box with 13 cm of external diameter and 8 cm of height, having …

Low sulphidation (LS) epithermal deposits are categorized as they represent the most distal parts of an intrusion - hydrothermal system. LS epithermal deposits form within 0.5 km - 2 km in depth at temperatures below 250 degrees C. Metals are deposited through the process of boiling fluids, fluid mixing, and vapor releas…

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 — Epithermal precious (± base) metal deposits are largely hosted by volcanic rocks, and the tops of ore bodies formed within 10s to several 100s m of the paleosurface (Lindgren, 1933) in ...

Epithermal and porphyry ore deposits develop in response to the plate tectonic process, typically as subduction-related partial melting gives rise to magmatism mainly within …

 — Epithermal gold deposits are among the richest gold deposits in the world, with some bonanza-grade ore shoots containing more than 1000 g/t gold-equivalent or a kilogram of gold for everyone tonne of rock mined. The tonnage of ore in epithermal veins is typically smaller than other types of low-grade gold deposits.. Gold mineralisation within …

 — Pamukkale's Terraces. A fascinating group and characteristic of Epithermal gold deposits is that you can virtually see them forming today, simply by visiting hot springs. Like those with …

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Epithermal gold deposits have size, geometry, and grade variations that can be broadly organized around some genetic classes and, therefore, influence the exploration approach or philosophy. Nearly 80 years ago, Waldemar Lindgren defined the epithermal environment as being shallow in depth, typically hosting deposits of Au, Ag, and base metals ...

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The successful exploration geologist uses knowledge of geologic relationships and ore-deposit styles, tempered by experience, to interpret all information available from a given prospect in order to develop an understanding of its mineral potential. In the case of exploration for epithermal gold deposits, this understanding can be augmented by …

 — Epithermal gold (± Cu & Ag) deposits form at shallower crustal levels than porphyry Cu-Au systems, and are primarily distinguished as low and high sulphidation using criteria of varying gangue ...

Shaft depth, mining scale, backfill type and mill throughput data. Full profiles of select mines and projects. Mines with autonomous mobile equipment. Equipment type, model, size and quantity. ... The Middle to Upper Jurassic ignimbrites and volcanic rocks of the Chon Aike Formation host the low-sulphidation epithermal gold and silver deposits ...

In the context of exploration for epithermal deposits, why study geothermal systems at all? After all, not one exploited system to date has been shown by drilling to harbor any economically significant metal resource--but then until recently not one had been drilled for other than geothermal energy exploration.* The latter involves drilling to ...

 — Epithermal gold deposits occur in and near the marginal fault that circumscribes the Goldfield, Nevada, Tertiary caldera. The gold occurs disseminated in alunite, pyrite, and kaolin- bearing silicified zones that are controlled by the circular faults.

Epithermal gold (± Cu & Ag) deposits form at shallower crustal levels than porphyry Cu-Au systems, and are primarily distinguished as low and high sulphidation using criteria of varying gangue and ore mineralogy, …

Simple Rules of Gold Geology: Comparing Epithermal and Mesothermal Deposits. July 2017 by Chris Ralph. Geology is a science of general tendencies with frequent exceptions, not one of hard and fast rules that are always true and never vary. For almost every well-accepted rule of gold deposits, I can point you to a number of important exceptions.

 — The Ban Houayxai is a structurally controlled epithermal gold-silver deposit hosted within an early Permian volcano-sedimentary sequence of the Trong Son Fold belt in the south western extremity of the Phu Bia Contract Area (Manaka et al. 2014).The deposit is located on a steep narrow north-south oriented ridge that protrudes into the Nam …

 — Epithermal mineralization is an important metallogenic criterion for volcanogenic belts of varying ages. We show that epithermal high-sulfidation deposits are shallow formations in volcanogenic ...

 — Epithermal ore at Lepanto-Far Southeast reflects a paleohydrologic regime dominated by lateral fluid flow, with a marked control by intersection of the Lepanto fault and a lithologic unconformity ...

 — Low-sulfidation (LS) epithermal deposits with major Ag and Au production are formed in shallow parts (<1 km) of magmatic-hydrothermal systems at moderate-low temperature conditions of 100 C to 300 C [1–5]. The ore-forming fluids of LS epithermal deposits have been fully investigated