Post by
diabase1 on May 31, 2023 8:56am
Kenogaming5
Drilling
There were only 2 drill holes put down on the West Magnetic Anomaly (WMA), one by Amax Potash Limited and one by J Salo. There was no drilling carried out on the East Magnetic Anomaly.
In 1979, Amax Potash Limited drilled a hole about the middle of the West Magnetic Anomaly (42A04NW8557/42A04NW8557), within an area of moderate magnetic intensity. It was not in an area of higher magnetic intensity. It was drilled to the south. The rocks reported were generally dunite, peridotite and chlorite schist. The alteration minerals were serpentine, talc and carbonate. The only mineralization reported were the previous alteration minerals, plus magnesite. There were also sections of crysotile and picrolite. There were no visible sulphides reported for most of the drill core. Towards the end of the hole, anomalous nickel values were reported. An anomalous nickel value of 0.25% occurs within a 'carbonated and serpentinized ultramafic'. The carbonated ultramafic is described as being a pale grey, fine grained, strongly carbonated ultramafic, with minor talc and chlorite rich bands throughout.
In 1997, J. Salo drilled one hole to the north, parallel and just to the east of the Amax drill hole. Most of the rock was dunite, but there were also some pyroclastic volcanic rocks as well (42A04NW2003/42A04NW2003). The latter possibly suggests that there may be two ultramafic sills within the large West Magnetic Anomaly. There was lots of talc and black asbestos. There was also very finely disseminated sulphides, with inclusions of pyrrhotite, pyrite and traces of chalcopyrite. The latter gave a blue green staining. The ultramafic rocks were highly serpentinized, along with an abundance of carbonatization.
Both drill holes showed an abundance of carbonate minerals.
Drilling took place in areas of lower magnetic intensity, not on the areas of much higher intensity magnetics. For me, that's a question!! Should the drilling be on lower magnetics or higher magnetics, when looking for nickel?
https://www.sciencedirect.com/science/article/abs/pii/S0892687522005763#:~:text=Awaruite%20has%20a%20density%20of,)%20(Seiler%2C%20et%20al.
"Awaruite is strongly magnetic. Awaruite has a density of 8.57 g/cm3, significantly higher than the main gangue mineral, serpentine (2.6 g/cm3), and has shown a high magnetic susceptibility (14.4 SI units), higher than magnetite (3.4 SI units)". However, even subtle magnetic anomalies within the large West Magnetic Anomaly could be of interest. If awaruite exists within the WMA, then moderate to higher magnetic intensity anomalies are the targets.
Amax was a south hole, with no visible sulphides, J. Salo was a north hole, with disseminated sulphides. Check Figure 4 on RT Minerals website, under Kenogaming. It seems as though Amax's drill hole may have been drilled down dip, while J. Salo's drill hole was drilled into the dip. Keep in mind that even though the ultramafic intrusive is still considered to be a sill, the layering effect of the magma, even after the movement from near horizontal to near vertical, is still thought to be slightly dipping to the south.
I thought the following article was enlightening, for me anyway. Check out the following website.
https://www.nature.com/articles/s41467-017-01610-4#Sec2
"In this study, we investigate magnetic anomaly changes related to natural serpentinite carbonation using regional, outcrop-, and thin section-scale magnetometry coupled with microtextural analysis of mineral replacement reactions. The results show that the magnetic character of distinct alteration product assemblages changes in response to the stability of magnetic carrier phases. Progressive serpentinite carbonation is characterized by a transient increase in the magnetic field strength during intermittent carbonation. The final alteration product is almost devoid of magnetic carrier phases and thus characterized by a very weak magnetic field strength. These findings indicate that magnetic field measurements can be used to detect carbonation fronts in the field and to monitor reaction progress in space and time".
However, is nickel more favourable, or prevalent, within a serpentinization or a carbonatization alteration environment?
Any future drilling targets should be based on the ground magnetic data and not the airborne data. The former data is more detailed, with respect to the magnetic data. It is suggested that RT Minerals should investigate the use of the magnetotelluric (MT) system on this type of nickeliferous ultramafic intrusive. It is sensitive to this type of mineralization, and has excellent depth of penetration. A high resolution magnetic survey should also be considered, in conjunction with the MT survey.