It's fine as long as the company clearly defines how the sample...

It's fine as long as the company clearly defines how the sample was collected, there are strict reporting rules around this. Any potential sample bias is implied, depending on the sampling method.

MKG state they collected these samples from spoil piles. You're correct in that by definition these samples would be "expected" to grade higher than a normal in-situ sample, because they're all samples of the orebody. Definitely a bit of marketing spin from MKG here, but within the rules.

By "in-situ", Geologists mean that the ground or sample has not been disturbed and therefore it represents the grade "in place" at the time of formation. Samples like drill core, RC chip samples, and vein chip samples are all in-situ samples.

Crucially, in-situ samples also provide information on the apparent true width of the orebody, which grab samples do not.

If these results had been reported from in-situ vein chip samples over a wider area, it'd definitely be a bit more exciting. But, another way to look at it would be to assume that all the spoil came from that one small artisinal mining area, so there could be a lot more high-grade that's still "in-situ" Bit of a glass half-empty vs. full situation.

But pretty crazy that such high-grade material was just sitting in a pile like that.