Re-Rate Timeline Opinion, page-20

This post is more for Mick...

In the past, I did some reading on the types of drilling technology applied for mineral exploration so that I can better understand the terminology used. The most common ones are air core (AC), reverse circulation (RC) and diamond (D) drilling. These are regularly mentioned in announcements and quarterly reports of all mineral exploration companies. My simplistic understanding is that:

1. AC is the cheapest and fastest, but it can only work under specific ground conditions and rock geology. Also, it can only go to a shallower depth compared to the other two techs.
2. RC is the better tech because it can perform under ground conditions and rock geology that air core cannot. It can also go twice as deep. But like, air core, the drill samples are crushed up in the process and are not accurate for exact ore grade and depth measurements. What's better is always more expensive, of course.
3. Diamond drilling is deployed to do what reverse circulation cannot, especially for bringing up those long rods of core samples that we see in reports. Can also go even deeper than RC. It is the most expensive of the three.

A question I have is about the drilling approach at ARL's Ni/Co tenements, which are hosted in the best-in-class goethite that is usually formed in clay. Goethite is not clay, though.

Goethite (FeO(OH)) is a complex iron oxide mineral with a variety of chemical properties that contribute to its behavior in different geological and environmental contexts - Geology Science.

"In Australia, goethite is predominantly associated with the vast iron ore deposits of the Hamersley Basin in Western Australia." Erick Ramanaidou, CSIRO. The CSIRO also stated that goethite is also found in other iron ore regions such as the Pilbara, Yilgarn, and the Middleback Ranges.

In contrast, clay minerals are a group of hydrous aluminosilicates that are formed from the weathering and alteration of silicate minerals. The chemical composition of clay minerals consists mainly of silica, alumina, and water - Geology Science.

From your drilling experience at KNP, is there a different approach used for drilling in predominantly clay ground as compared to predominantly non-clay ground?
How does a driller know in advance, though?

The reason for this question is to put to rest, if possible, an unsubstantiated comment made about ARL's Ni/Co being uneconomic to process because of its high clay content. To me, having a high clay content suggests a predominantly clay ground.
But Erick's comment above seems to suggest that Australian goethite at KNP might not necessarily be found in clay, as might usually be the case in other countries.
The commentator very likely generalised the association between goethite and clay and then tried to pin that one onto KNP just to score a dubious point.

Thanks in advance, Mick.