You're right. Grab sample assays can be undoubtedly influenced by the discretionary selection of the samples. If the sampler only selects the "juicy", mineralized portions of the vein/rock (as opposed to more representative sampling), then gold concentrations are going to be higher...and higher assays will be returned. Also, a grab sample can consist of approximately a "handful of rock", so again it's easy to see (from a size perspective) that grab samles may not necessarily be representative of the entire zone or vein. Having said that, typically when selecting grab samples you do select a variety of samples though, obviously, only the higher grade ones get reported. So, you would for example collect a variety of samples along the vein as well as samples along the adjacent wall rock as well as samples in the host rock to get an overall picture of the mineralization concentration. Having said that, grab samples are a key part of prospecting as they provide an initial glimpse of a zones potential mineralization and flag areas for further more detailed work (e.g. trenching).
In a previous nr, the company did state that they were going to perform channel samples during the trenching process where possible. This is a more representative form of sampling. A rock saw is used to cut a channel across a specified width of the zone. The channel is a couple inches across and usually an inch or two in depth. Think a "horizontal drill hole" across the surface of the rock if that makes sense. The entire channel cut for the sample is then sent to assay...no selecting of higher grade material - the whole thing goes.
Having said all this, it's important to closely check the reported intervals in sampling. How many times have you seen something like 10 m grading 13 g Au/t including 0.3 m grading 152 g Au/t. That 0.3m interval has been "averaged" across a 10 m width creating a very misleading interval. This very narrow 0.3m zone could probably not be mined because of the dilution that would occur from the 2.5 m barren rock. So, if nothing else, investors really need to closely examine results and how they're presented in nrs because despite NI43101 regulations, the presentation can be very misleading.
On another note, as I stated a couple weeks ago, I did sell all of my SXL holdings in one account for tax loss purposes; but still hold some in another account. At the end of July we had $300,000 in cash. I strongly suspect that's now down to about $100,000. There will need to be a financing soon and I think the company is getting positioned to do so...an increase in the sp (from 0.20-0.40) and management attending the "dog and pony shows" lately. I'll hopefully buy back my position during "tax loss season" later on. We'll see...Goodness knows I've been wrong in the past, and will be the first to admit it.
At any rate, have a great weekend.