Portable X-Ray Fluorescence Analyzers and their use in an Underground Exploration Program for Tin

1979 ◽  
Vol 23 ◽  
pp. 19-25
Author(s):  
Mark W. Springett
Keyword(s):  
Mining Industry ◽  
Analytical Techniques ◽  
Drill Core ◽  
Current Interest ◽  
X Ray ◽  
Core Samples ◽  
South West ◽  
Surface Exploration ◽  
Fluorescence Analyzer ◽  
South West England

In 1968 Consolidated Gold Fields commenced exploration below adit level at the Wheal Jane tin prospect in south-west England. During the surface exploration program the relatively recently introduced Portable X-ray Fluorescence Analyzer (“P.I.F.“) had been used for semi-quantitative scanning of drill core and for providing preliminary assays for tin on prepared core samples. The P.I.F. was introduced to the mining industry in 1965 (Bowie et. al. (1) and had originally been equipped specifically for tin analysis due to the current interest in tin exploration, the difficulties of chemically assaying for tin and the suitability of tin to X-ray analytical techniques. The instrumentation and principals of operation have been described by Bowie (1,2). At Wheal Jane the need to obtain rapid analyses to help control underground development and difficulties in visually recognizing the tin mineralization made the prospect an excellent testing ground for the practical aspects of the instrument.

Tin-bearing sulphides from St Michael's Mount and Cligga Head, Cornwall

1984 ◽  
Vol 48 (348) ◽  
pp. 389-396 ◽  
Author(s):  
F. Moore ◽  
R. A. Howie
Keyword(s):  
Optical Properties ◽  
Electron Probe ◽  
Optical Data ◽  
X Ray ◽  
Cautious Approach ◽  
South West ◽  
South West England

Abstract The result of electron probe microanalyses, along with X-ray and optical data obtained for tin sulphides from two different localities in south-west England indicate that the mineral hitherto described from St Michael’s Mount as stannite is in fact kesterite, Cu2(Fe0.23Zn0.77)SnS4. The yellow ‘stannite’ reported from this locality proved to be stannoidite, Cu8(Fe2.39 Zn0.61)SnS2S12. Kesterite, Cu2(Fe0.09Zn0.90SnS4, and zincian stannite, Cu2(Fe0.63Zn0.38)SnS4, are also reported from Cligga Head. It is suggested that a more cautious approach should be taken in identifying these tin sulphides solely on their optical properties.

scholarly journals Quantitative Mineral Mapping of Drill Core Surfaces I: A Method for µXRF Mineral Calculation and Mapping of Hydrothermally Altered, Fine-Grained Sedimentary Rocks from a Carlin-Type Gold Deposit

2020 ◽  
Author(s):  
Rocky D. Barker ◽  
Shaun L.L. Barker ◽  
Siobhan A. Wilson ◽  
Elizabeth D. Stock
Keyword(s):  
Gold Deposit ◽  
Sedimentary Rocks ◽  
Potassium Feldspar ◽  
Ore Deposits ◽  
Drill Core ◽  
Raster Data ◽  
X Ray ◽  
Fine Grained ◽  
Core Samples ◽  
Wavelength Dispersive Spectrometry

Abstract Mineral distributions can be determined in drill core samples from a Carlin-type gold deposit, using micro-X-ray fluorescence (µXRF) raster data. Micro-XRF data were collected using a Bruker Tornado µXRF scanner on split drill core samples (~25 × 8 cm) with data collected at a spatial resolution of ~100 µm. Bruker AMICS software was used to identify mineral species from µXRF raster data, which revealed that many individual sample spots were mineral mixtures due to the fine-grained nature of the samples. In order to estimate the mineral abundances in each pixel, we used a linear programming (LP) approach on quantified µXRF data. Quantification of µXRF spectra was completed using a fundamental parameters (FP) standardless approach. Results of the FP method compared to standardized wavelength dispersive spectrometry (WDS)-XRF of the same samples showed that the FP method for quantification of µXRF spectra was precise (R2 values of 0.98–0.97) although the FP method gave a slight overestimate of Fe and K and an underestimate of Mg abundance. Accuracy of the quantified µXRF chemistry results was further improved by using the WDS-XRF data as a calibration correction before calculating mineralogy using LP. The LP mineral abundance predictions were compared to Rietveld refinement results using X-ray diffraction (XRD) patterns collected from powders of the same drill core samples. The root mean square error (RMSE) for LP-predicted mineralogy compared to quantitative XRD results ranges from 0.91 to 7.15% for quartz, potassium feldspar, pyrite, kaolinite, calcite, dolomite, and illite. The approaches outlined here demonstrates that µXRF maps can be used to determine mineralogy, mineral abundances, and mineralogical textures not visible with the naked eye from fine-grained sedimentary rocks associated with Carlin-type Au deposits. This approach is transferrable to any ore deposit, but particularly useful in sedimentary-hosted ore deposits where ore and gangue minerals are often fine grained and difficult to distinguish in hand specimen.

Refining 2 km of Ordovician chronostratigraphy beneath Anticosti Island utilizing integrated chemostratigraphy

2016 ◽  
Vol 53 (8) ◽  
pp. 865-874 ◽  
Author(s):  
Patrick I. McLaughlin ◽  
Poul Emsbo ◽  
André Desrochers ◽  
Alyssa Bancroft ◽  
Carlton E. Brett ◽  
...  
Keyword(s):  
High Resolution ◽  
Elemental Composition ◽  
Drill Core ◽  
Depositional Sequences ◽  
X Ray ◽  
Calcareous Shale ◽  
Trace Elemental ◽  
Anticosti Island ◽  
Fluorescence Analyzer

New high-resolution chemostratigraphy, in combination with updated biostratigraphy, refines the chronostratigraphic resolution of the nearly 2 km thick Ordovician section below Anticosti Island. A total of 1414 horizons, spaced at 1.0–1.5 m intervals, were sampled from the New Associated Consolidated Paper (NACP) drill core and analyzed for major and trace elemental composition by portable X-ray fluorescence analyzer (pXRF). Select micrite and calcareous shale powders were then analyzed for δ13Ccarb (number of samples, N = 364) and 87Sr/86Sr (N = 25). Our results indicate a Floian to early Darriwilian (F3–Dw1) age for the Romaine Formation, a middle Darriwilian to Sandbian (Dw2–Sa1) age for the Mingan Formation, a lower to mid-Katian (Ka1–Ka2) age for the Macasty Formation, an upper Katian (Ka3) age for the lower Vauréal Formation, an uppermost Katian (Ka4) age for the upper Vauréal, and a Hirnantian (H1) age for the Ellis Bay Formation. This integrated chemostratigraphic and biostratigraphic synthesis establishes the position of numerous unconformities, the duration of the intervening depositional sequences, and rates of sedimentation.

3D modelling of a mineral deposit using drill core hyperspectral data

2020 ◽  
Author(s):  
Roberto De La Rosa ◽  
Mahdi Khodadadzadeh ◽  
Cecilia Contreras ◽  
Laura Tusa ◽  
Moritz Kirsch ◽  
...  
Keyword(s):  
Categorical Data ◽  
Near Infrared ◽  
Mining Industry ◽  
Structural Features ◽  
Derived Categories ◽  
Hyperspectral Data ◽  
Drill Core ◽  
Data Set ◽  
Core Samples ◽  
Core Logging

<p><span>Drill core samples have been traditionally used by the mining industry to make resource estimations and to build geological models. The hyperspectral drill core scanning has become a popular tool in mineral exploration because it provides a non-destructive method to rapidly characterise structural features, alteration patterns and rock mineralogy in a cost effective way. </span></p><p><span>Typically, the hyperspectral sensors cover a wide spectral range from visible and near-infrared (VNIR) to short and long wave infrared (SWIR and LWIR). The spectral features in this range will help to characterize a large number of mineral phases and complement the traditional core logging techniques. The hyperspectral core scanning provide mineralogical information in a millimetre scale for the entire borehole, which fills the gap between the microscopic scale of some of the laboratory analytical methods or the sparse chemical assays and the meter scale from the lithological descriptions.</span></p><p><span>However, applying this technique to the core samples of an entire ore deposit results in big datasets. Therefore, there is the need of a workflow to build a 3D geological model conditioned by the data applying suitable data reduction methods and appropriate interpolation techniques.</span></p><p><span>This contribution presents a case study in the combination of traditional core logging and hyperspectral core logging for geological modelling. To attain mineral and alteration maps from the hyperspectral data, unsupervised classification techniques were applied generating a categorical data set. The amount of data was reduced by the application of a domain generation algorithm based on the hyperspectral information. The domain generated by the algorithm is a compositional categorical data set that was then fed to condition the application of stochastic Plurigaussian simulations in the construction of 3D models of geological domains. This technique allows to simulate the spatial distribution of the hyperspectral derived categories, to make a resource estimation and to calculate its associated uncertainty.</span></p>

Quantitative Analysis of 300 and 400 Series Stainless Steel by Energy Dispersive X-Ray Fluorescence

1978 ◽  
Vol 22 ◽  
pp. 395-400
Author(s):  
Bradner D. Wheeler ◽  
Nancy Jacobus
Keyword(s):  
Stainless Steel ◽  
Analytical Techniques ◽  
Major Elements ◽  
Energy Dispersive ◽  
Absolute Methanol ◽  
X Ray ◽  
Minor Elements ◽  
Recent Developments ◽  
Successful Analysis ◽  
Fluorescence Analyzer

Recent developments in analytical techniques and software have allowed the accurate quantitative determinations of both the major and minor elements in stainless steels by energy dispersive x-ray fluorescence. The successful analysis of 300 and 400 series stainless steel is reported utilizing this technique. The analysis of this type of material represents one of the most severe tests of the method due to numerous peak overlaps and interelement effects such as absorption and enhancement.Sixteen standards of ASTM 300 series and ten 400 series were prepared by polishing on a 220 grit aluminum oxide belt and subsequently washing the surface in absolute methanol. Analyses were performed with an EG&G ORTEC 6110 Tube Excited Fluorescence Analyzer utilizing a dual anode (Rh/W) x-ray tube. Peak deconvolutions and interelement corrections were made with a 16K PDP-11/05 computer utilizing the program FLINT (1). Utilization of spectral deconvolutions and interelement corrections yields a relative accuracy of approximately IX of the concentrations of the major elements.

Four new uranium–lead ages from Cornwall

1964 ◽  
Vol 33 (267) ◽  
pp. 1081-1092 ◽  
Author(s):  
R. P. C. Pockley
Keyword(s):  
Progressive Increase ◽  
Oxidation States ◽  
X Ray ◽  
South West ◽  
South West England

SummaryFour new isotopic U/Pb ages from Cornwall are reported. The Pb206/U238 and Pb207/U235 ages for each specimen are concordant. The Pb206/U238 ages are : South Terras mine 225 ± 5 million years (Myr.), Redruth Area 124 ± 4 Myr., Wheal Owles mine 58 ± 3 Myr., and South Terras Area 62 ± 3 Myr. Cell sizes, calculated from X-ray powder photographs, decrease with decreasing ages of the specimens, indicating a progressive increase in the oxidation states of the uranium present. It is concluded tentatively that at least two periods of mineralization affected south-west England at about 290 Myr. and 225 Myr., and that a final event occurred at about 60 Myr. Whether this final event involved the remobilization of older uranium with loss of lead, or the introduction of additional uranium, or a combination of both effects cannot be established from this evidence. No unique explanation has been made for the 124 Myr. age.

Intracellular inclusions in the nematode Tripyloides marinus from metal-enriched and cleaner estuaries in Cornwall, south-west England

1996 ◽  
Vol 76 (4) ◽  
pp. 885-895 ◽  
Author(s):  
R. N. Millward
Keyword(s):  
Metal Contamination ◽  
Marine Nematode ◽  
Defence Mechanism ◽  
Granule Formation ◽  
X Ray ◽  
South West ◽  
Transmission Electron ◽  
Detoxification System ◽  
A Site ◽  
South West England

Two types of electron-dense inclusions are described using transmission electron microscopy from the marine nematode Tripyloides marinus (Nematoda; BÜtshli, 1874) isolated from a metal-enriched site and a site of low metal contamination. These were classified as granular, intracellular inclusions in the intestinal syncytium, and fluid-filled vesicles along the cuticular margin of the epidermis. Energy-dispersive x-ray analysis (EDX) showed that the intestinal granules were largely comprised of P and S, with variable levels of Ca, Cu, Zn, Fe and Br, and that the epidermal vesicles contained high levels of Br and S with variable levels of Ca, Cu, Zn, Fe and P. It is suggested that intestinal granule formation may be involved in the detoxification of heavy metal sulphides and might result in a heightened ability of the species to colonize metal-enriched sediments. The function of the cuticular vesicles is unclear, but might be linked to a predatory or microbial defence mechanism (Woodin et al., 1987), or as part of a metal detoxification system.

Energy-dispersive x-ray microanalysis in the earth sciences

1992 ◽  
Vol 50 (2) ◽  
pp. 1740-1741
Author(s):  
N. G. Ware
Keyword(s):  
Mineral Exploration ◽  
Energy Dispersive Spectrometer ◽  
Mining Industry ◽  
Silicon Detector ◽  
Analytical Techniques ◽  
Experimental Petrology ◽  
Energy Dispersive ◽  
X Ray ◽  
The 1960S ◽  
Almost All

The electron microprobe analyser (EMPA) is used extensively for the analysis of the constituent minerals in rocks and the samples generated by experimental petrology apparatus. These analyses, combined with the results of field observations and data from other analytical techniques, are used in petrogenetic studies and hence in the determination of planetary formation and evolution. In turn, this knowledge helps the mining industry in their mineral exploration programs.In the 1960s almost all geological usage of the EMPA was confined to the x-ray spectrometry of L3-K lines of elements of atomic number 11 through 30 (Na through Zn). By the end of this decade semi conductor technology had advanced so that these x-ray lines could be resolved using a lithium-drifted silicon detector working as an energy dispersive spectrometer (EDS). Quantitative EDS software was developed in the early 1970s and it became possible to perform major element analyses of silicates, oxides, carbonates and sulphides using a scanning electron microscope (SEM) fitted with an EDS.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Layered and ion implantation specimens as possible reference materials for the electron-probe microanalysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1652-1653
Author(s):  
G. Remond ◽  
R.H. Packwood ◽  
C. Gilles ◽  
S. Chryssoulis
Keyword(s):  
Ion Implantation ◽  
Reference Materials ◽  
Analytical Techniques ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
X Ray ◽  
Spatially Resolved ◽  
Analytical Expressions ◽  
Original Approach ◽  
Depth Concentration

Merits and limitations of layered and ion implanted specimens as possible reference materials to calibrate spatially resolved analytical techniques are discussed and illustrated for the case of gold analysis in minerals by means of x-ray spectrometry with the EPMA. To overcome the random heterogeneities of minerals, thin film deposition and ion implantation may offer an original approach to the manufacture of controlled concentration/ distribution reference materials for quantification of trace elements with the same matrix as the unknown.In order to evaluate the accuracy of data obtained by EPMA we have compared measured and calculated x-ray intensities for homogeneous and heterogeneous specimens. Au Lα and Au Mα x-ray intensities were recorded at various electron beam energies, and hence at various sampling depths, for gold coated and gold implanted specimens. X-ray intensity calculations are based on the use of analytical expressions for both the depth ionization Φ (ρz) and the depth concentration C (ρz) distributions respectively.

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