Automated Gold Grain Counting. Part 2: What a Gold Grain Size and Shape Can Tell!
Glacial drift exploration methods are well established and widely used by mineral industry exploring for blind deposit in northern territories, and rely on the dispersion of mineral or chemical signal in sediments derived from an eroded mineralized source. Gold grains themselves are the prime indica...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-04-01
|
| Series: | Minerals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-163X/11/4/379 |
| _version_ | 1797538960587620352 |
|---|---|
| author | Réjean Girard Jonathan Tremblay Alexandre Néron Hugues Longuépée Sheida Makvandi |
| author_facet | Réjean Girard Jonathan Tremblay Alexandre Néron Hugues Longuépée Sheida Makvandi |
| author_sort | Réjean Girard |
| collection | DOAJ |
| description | Glacial drift exploration methods are well established and widely used by mineral industry exploring for blind deposit in northern territories, and rely on the dispersion of mineral or chemical signal in sediments derived from an eroded mineralized source. Gold grains themselves are the prime indicator minerals to be used for the detection of blind gold deposits. Surprisingly, very little attention has been dedicated to the information that size and shape of gold grain can provide, other than a simple shape classification based on modification affecting the grains that are induced in the course of sediment transport. With the advent of automated scanning electron microscope (SEM)-based gold grain detection, high magnification backscattered electron images of each grain are routinely acquired, which can be used for accurate size measurement and shape analysis. A library with 88,613 gold grain images has been accumulated from various glacial sediment surveys on the Canadian Shield and used to detect trends in grains size and shape. A series of conclusions are drawn: (1) grain size distribution is consistent among various surveys and areas, (2) there is no measurable fine-grained gold loss due to natural elutriation in ablation or reworked till, or during the course of reverse circulation drilling, (3) there is no grain size sorting during glacial transport, severing small grains from large ones, (4) shape modification induced by transport is highly dependent on grain size and original shapes, and (5) the use of grain shape inherited from neighboring minerals in the source rocks is a useful feature when assessing deposit types and developing exploration strategies. |
| first_indexed | 2024-03-10T12:38:37Z |
| format | Article |
| id | doaj.art-5ecdb0994abb49669b3b02a6295b5b05 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T12:38:37Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-5ecdb0994abb49669b3b02a6295b5b052023-11-21T14:04:45ZengMDPI AGMinerals2075-163X2021-04-0111437910.3390/min11040379Automated Gold Grain Counting. Part 2: What a Gold Grain Size and Shape Can Tell!Réjean Girard0Jonathan Tremblay1Alexandre Néron2Hugues Longuépée3Sheida Makvandi4IOS Services Géoscientifiques Inc., Chicoutimi, QC G7J 3Y2, CanadaIOS Services Géoscientifiques Inc., Chicoutimi, QC G7J 3Y2, CanadaIOS Services Géoscientifiques Inc., Chicoutimi, QC G7J 3Y2, CanadaIOS Services Géoscientifiques Inc., Chicoutimi, QC G7J 3Y2, CanadaIOS Services Géoscientifiques Inc., Chicoutimi, QC G7J 3Y2, CanadaGlacial drift exploration methods are well established and widely used by mineral industry exploring for blind deposit in northern territories, and rely on the dispersion of mineral or chemical signal in sediments derived from an eroded mineralized source. Gold grains themselves are the prime indicator minerals to be used for the detection of blind gold deposits. Surprisingly, very little attention has been dedicated to the information that size and shape of gold grain can provide, other than a simple shape classification based on modification affecting the grains that are induced in the course of sediment transport. With the advent of automated scanning electron microscope (SEM)-based gold grain detection, high magnification backscattered electron images of each grain are routinely acquired, which can be used for accurate size measurement and shape analysis. A library with 88,613 gold grain images has been accumulated from various glacial sediment surveys on the Canadian Shield and used to detect trends in grains size and shape. A series of conclusions are drawn: (1) grain size distribution is consistent among various surveys and areas, (2) there is no measurable fine-grained gold loss due to natural elutriation in ablation or reworked till, or during the course of reverse circulation drilling, (3) there is no grain size sorting during glacial transport, severing small grains from large ones, (4) shape modification induced by transport is highly dependent on grain size and original shapes, and (5) the use of grain shape inherited from neighboring minerals in the source rocks is a useful feature when assessing deposit types and developing exploration strategies.https://www.mdpi.com/2075-163X/11/4/379goldtillglacial sedimentsgold grain morphologygold grain sizeautomated SEM |
| spellingShingle | Réjean Girard Jonathan Tremblay Alexandre Néron Hugues Longuépée Sheida Makvandi Automated Gold Grain Counting. Part 2: What a Gold Grain Size and Shape Can Tell! Minerals gold till glacial sediments gold grain morphology gold grain size automated SEM |
| title | Automated Gold Grain Counting. Part 2: What a Gold Grain Size and Shape Can Tell! |
| title_full | Automated Gold Grain Counting. Part 2: What a Gold Grain Size and Shape Can Tell! |
| title_fullStr | Automated Gold Grain Counting. Part 2: What a Gold Grain Size and Shape Can Tell! |
| title_full_unstemmed | Automated Gold Grain Counting. Part 2: What a Gold Grain Size and Shape Can Tell! |
| title_short | Automated Gold Grain Counting. Part 2: What a Gold Grain Size and Shape Can Tell! |
| title_sort | automated gold grain counting part 2 what a gold grain size and shape can tell |
| topic | gold till glacial sediments gold grain morphology gold grain size automated SEM |
| url | https://www.mdpi.com/2075-163X/11/4/379 |
| work_keys_str_mv | AT rejeangirard automatedgoldgraincountingpart2whatagoldgrainsizeandshapecantell AT jonathantremblay automatedgoldgraincountingpart2whatagoldgrainsizeandshapecantell AT alexandreneron automatedgoldgraincountingpart2whatagoldgrainsizeandshapecantell AT hugueslonguepee automatedgoldgraincountingpart2whatagoldgrainsizeandshapecantell AT sheidamakvandi automatedgoldgraincountingpart2whatagoldgrainsizeandshapecantell |