scholarly journals Current Techniques and Applications of Mineral Chemistry to Mineral Exploration; Examples from Glaciated Terrain: A Review

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Daniel Layton-Matthews ◽  
M. Beth McClenaghan
Keyword(s):  
Mineral Exploration ◽  
Mineral Chemistry ◽  
Heavy Mineral ◽  
Optical Identification ◽  
Glacial Sediments ◽  
Volcanogenic Massive Sulfides ◽  
Kimberlite Indicator Minerals ◽  
Indicator Mineral ◽  
Automated Mineralogy ◽  
Indicator Minerals

This paper provides a summary of traditional, current, and developing exploration techniques using indicator minerals derived from glacial sediments, with a focus on Canadian case studies. The 0.25 to 2.0 mm fraction of heavy mineral concentrates (HMC) from surficial sediments is typically used for indicator mineral surveys, with the finer (0.25–0.50 mm) fraction used as the default grain size for heavy mineral concentrate studies due to the ease of concentration and separation and subsequent mineralogical identification. Similarly, commonly used indicator minerals (e.g., Kimberlite Indicator Minerals—KIMs) are well known because of ease of optical identification and their ability to survive glacial transport. Herein, we review the last 15 years of the rapidly growing application of Automated Mineralogy (e.g., MLA, QEMSCAN, TIMA, etc) to indicator mineral studies of several ore deposit types, including Ni-Cu-PGE, Volcanogenic Massive Sulfides, and a variety of porphyry systems and glacial sediments down ice of these deposits. These studies have expanded the indicator mineral species that can be applied to mineral exploration and decreased the size of the grains examined down to ~10 microns. Chemical and isotopic fertility indexes developed for bedrock can now be applied to indicator mineral grains in glacial sediments and these methods will influence the next generation of indicator mineral studies.

scholarly journals Exploration Potential of Fine-Fraction Heavy Mineral Concentrates from Till Using Automated Mineralogy: A Case Study from the Izok Lake Cu–Zn–Pb–Ag VMS Deposit, Nunavut, Canada

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 310 ◽  
Author(s):  
H. Donald Lougheed ◽  
M. Beth McClenaghan ◽  
Dan Layton-Matthews ◽  
Matthew Leybourne
Keyword(s):  
Mineral Exploration ◽  
Fine Fraction ◽  
Test Site ◽  
Massive Sulfide ◽  
Heavy Mineral ◽  
Morphological Data ◽  
Indicator Mineral ◽  
Automated Mineralogy ◽  
Sediment Cover ◽  
Liberation Analysis

Exploration under thick glacial sediment cover is an important facet of modern mineral exploration in Canada and northern Europe. Till heavy mineral concentrate (HMC) indicator mineral methods are well established in exploration for diamonds, gold, and base metals in glaciated terrain. Traditional methods rely on visual examination of >250 µm HMC material, however this study applies modern automated mineralogical methods (mineral liberation analysis (MLA)) to investigate the finer (<250 µm) fraction of till HMC. Automated mineralogy of finer material allows for rapid collection of precise compositional and morphological data from a large number (10,000–100,000) of heavy mineral grains in a single sample. The Izok Lake volcanogenic massive sulfide (VMS) deposit, one of the largest undeveloped Zn–Cu resources in North America, has a well-documented fan-shaped indicator mineral dispersal train and was used as a test site for this study. Axinite, a VMS indicator mineral difficult to identify optically in HMC, is identified in till samples up to 8 km down ice. Epidote and Fe-oxide minerals are identified, with concentrations peaking proximal to mineralization. Corundum and gahnite are intergrown in till samples immediately down ice of mineralization. Till samples also contain chalcopyrite and galena up to 8 km down ice of mineralization, an increase from 1.3 km for sulfide minerals in till previously reported for coarse HMC fractions. Some of these sulfide grains occur as inclusions within chemically and physically robust mineral grains and would not be identified visually in the coarse HMC visual counts. Best practices for epoxy mineral grain mounting and abundance reporting are presented along with the automated mineralogy of till samples down ice of the deposit.

scholarly journals Investigating the diamond potential of southern West Greenland

2004 ◽  
Vol 4 ◽  
pp. 69-72 ◽  
Author(s):  
Sven Monrad Jensen ◽  
Karsten Secher
Keyword(s):  
Structural Control ◽  
Mineral Chemistry ◽  
Mantle Xenoliths ◽  
Comprehensive Overview ◽  
West Greenland ◽  
Large Samples ◽  
Indicator Mineral ◽  
The Government ◽  
Indicator Minerals ◽  
Diamond Potential

Southern West Greenland hosts a province of ultramafic alkaline rocks, including swarms of dykes traditionally described as kimberlites and lamproites (Larsen 1991; Jensen et al. 2002). Since the mid-1990s, commercial diamond exploration has been focused on the Sarfartoq region and the region south-east of Maniitsoq (Fig. 1), and has resulted in numerous reports of diamond-favourable indicator minerals from till sampling, finds of kimberlitic dykes, and recovery of diamonds from kimberlitic rocks. A new digital compilation of company data released from confidential status (Jensen et al. 2003a) presents a comprehensive overview of exploration activities and results that have emerged since the Survey’s first compilation of occurrences of kimberlitic and related rocks (Larsen 1991). The new compilation in a GIS (geographic information system) environment allows for refined assessment of the distribution, structural control and possible spatial and petrogenetic relationships that characterise the kimberlitic occurrences. In 2003, the Geological Survey of Denmark and Greenland (GEUS) and the Government of Greenland’s Bureau of Minerals and Petroleum (BMP) went further than has been customary in investigating the economic potential of specific sites. Four areas were temporarily closed to application for exploration licences, pending sampling and testing for diamond content of large samples of more than one tonne each from significant kimberlitic occurrences. Additional characterisation and research initiated on these and other occurrences include magnetic mapping, detailed petrography and studies of mantle xenoliths, as well as indicator mineral chemistry. An extensive programme to determine the ages of kimberlitic and related rocks was also initiated in 2003.

scholarly journals Chemical studies of kimberlite indicator minerals from stream sediment and till samples in the southern Mackenzie region (NTS 85B, C, F, G), Northwest Territories, Canada

2021 ◽  
Author(s):  
I R Smith ◽  
S J A Day ◽  
R C Paulen ◽  
D G Pearson
Keyword(s):  
Rare Earth ◽  
Northwest Territories ◽  
Stream Sediment ◽  
Chemical Analyses ◽  
Great Slave Lake ◽  
Chemical Studies ◽  
Kimberlite Indicator Minerals ◽  
Indicator Mineral ◽  
Indicator Minerals ◽  
Field Area

Till (n=196) and stream sediment (n=60) samples were collected in the area south and west of Great Slave Lake, Northwest Territories (NTS 85B, C, F, and G), over the course of 3 summer field seasons. Samples were processed to recover kimberlite and other indicator minerals. This report summarizes results of the kimberlite indicator mineral (KIM) studies, including measures of KIM mineral types, abundances, and chemistry (major, trace, and rare earth elements). KIMs were present in 24% of the samples collected, and only 183 KIM grains in total were recovered, of which Cr-pyrope garnets were the most abundant (65.6%). Chemical analyses revealed strong similarities to the Drybones Bay and Mud Lake kimberlites which are situated 50 to &amp;gt;100 km to the northeast, roughly aligned with prominent glacially streamlined landform flowsets in this field area. Results suggest there is little evidence for undetected kimberlite outcrop or sub-crop in the study area.

scholarly journals Automated Indicator Mineral Analysis of Fine-Grained Till Associated with the Sisson W-Mo Deposit, New Brunswick, Canada

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 103
Author(s):  
H. Donald Lougheed ◽  
M. Beth McClenaghan ◽  
Daniel Layton-Matthews ◽  
Matthew I. Leybourne ◽  
Agatha Natalie Dobosz
Keyword(s):  
Mineral Exploration ◽  
Test Site ◽  
Coarse Fraction ◽  
Heavy Mineral ◽  
Optical Methods ◽  
Morphological Data ◽  
Fine Grained ◽  
Ore Minerals ◽  
Indicator Mineral ◽  
Liberation Analysis

Exploration under thick glacial sediment cover is an important facet of modern mineral exploration in Canada and northern Europe. Till heavy mineral concentrate (HMC) indicator mineral methods are well established in exploration for diamonds, gold, and base metals in glaciated terrain. Traditional methods rely on visual examination of >250 µm HMC material. This study applies mineral liberation analysis (MLA) to investigate the finer (<250 µm) fraction of till HMC. Automated mineralogy (e.g., MLA) of finer material allows for the rapid collection of precise compositional and morphological data from a large number (10,000–100,000) of heavy mineral grains in a single sample. The Sisson W-Mo deposit has a previously documented dispersal train containing the ore minerals scheelite, wolframite, and molybdenite, along with sulfide and other accessory minerals, and was used as a test site for this study. Wolframite is identified in till samples up to 10 km down ice, whereas in previous work on the coarse fraction of till it was only identified directly overlying mineralization. Chalcopyrite and pyrite are found up to 10 km down ice, an increase over 2.5 and 5 km, respectively, achieved in previous work on the coarse fraction of the same HMC. Galena, sphalerite, arsenopyrite, and pyrrhotite are also found up to 10 km down ice after only being identified immediately overlying mineralization using the >250 µm fraction of HMC. Many of these sulfide grains are present only as inclusions in more chemically and robust minerals and would not be identified using optical methods. The extension of the wolframite dispersal train highlights the ability of MLA to identify minerals that lack distinguishing physical characteristics to aid visual identification.

Sign in / Sign up

Export Citation Format

Share Document