Mon, Dec 2, 2013
to: DNRWAMINING-GOGEBICTACONITE@wisconsin.gov,
subject: G-Tac Bulk sampling
Hello Larry:
This is Jack Parker, an ancient (83) mining engineer/geologist from Baltic, near Houghton in the UP.
I have been following the G-Tac story since Day One, even before that, and have just read thru their modified bulk -sampling proposal.
I have a couple of questions and would appreciate your thoughtful response to them.
1. I see that sample pit #4 has been removed from the locations to be sampled, apparently because grunerite is there in plain sight.
How can the sampling be supposed to be representative if the one sampling site where grunerite is obviously present is intentionally excluded from sampling? It cannot, right?
2. The text expresses a belief that asbestiform minerals will not be present in the deposit.
How can such a statement be justified before sampling is concluded? It cannot, right?
In fact can we not expect to find them in or adjacent to any intrusions of magma in the ancient sediments?
3. Blasting as a way to sample the rock has been excluded, apparently because of potential dispersal of undesirable dusts.
I think that careful blasting by experienced people will be OK.
A couple of years ago new sewer pipelines were laid in trenches in Baltic, where we live, and there was much basaltic bedrock which had to be blasted to form trenches 3-5ft wide and as much as 10ft deep. One passed within 30 ft of our house.
Where close to dwellings the blastholes were loaded lightly and stemmed, then covered with soil and a heavy steel shield, maybe 1/2" thick, and slightly arched, set in place with a heavy-duty forklift. Away from dwellings the holes were detonated in sequence, maybe 1/4 sec delays, and we could watch them pop up in turn like molehills, with barely a puff of dust or smoke. The broken rock lay in a long continuous hump maybe 9" above the original surface.
Close to dwellings, with the blast shields, we could see no throw.
Most of the blasted rock was dug out with a big backhoe. In a few places a massive red rhyolite had to be hammered before digging. A hydraulic hammer with a pointed tool mounted on the backhoe boom did that job.
An apple tree about 6" in diameter was tilted, pushed upright again and the soil was tamped and watered. The tree has survived, minus a couple of branches.
4. I would object to taking samples from existing pits and rockpiles because it has been subjected to many years of weathering and washing. It is not representative of the rockmass.
I look forward to a constructive response