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Tanzanian Mineral Properties- The Mkuvia Project - Paleo-placer Developing

Message: Mkuvia Deposit Model? - Coastal Sand -Aussie style

Mkuvia Deposit Model? - Coastal Sand -Aussie style

posted on Jul 13, 2009 05:54PM

Heavy mineral sands potential of the Eucla Basin in South Australia

I have posted this paper at this link it is a published report on the mineral sand deposits on the southern coastal margin of Australia.


These coastal deposits contain heavy mineral sands (rutile, ilmenite, etc) that are mined at a profit. They are huge coastal sand deposits.

As a ‘Citizen Scientist’, working unfunded with other coastal scientists and engineers, I have participated in research on coastal sand deposits and have given papers at international conferences of coastal scientists on fluvial and marine sand mining. I look at the illustrations in this paper and feel that IMCO the gold at Mkuvia would be concentrated with the “black” sand (heavy mineral sands – HMS) if Mkuvia is in fact a coastal sand deposit. These zones of concentrated values are clearly illustrated by the authors in the Australian analouge. Is this Mkuvia, on steroids??

I have forwarded to and discussed the content of the paper with Laurie Stephenson via email and relayed my view the Mkuvia discovery to Laurie, Toby and Harp. A couple of things... The test pits at Mkuvia are 12 meters, at the deepest. It has been said that placer gold is found at or near bedrock. Look at the thickness of the Aussie sands, 12 meters just penetrates the upper zone of these Australian analogues.

History of placer mining has shown that not all placer ground is rich and that there is a high degree of variability of gold content within placer deposits; narrow pay-streaks in channel flows, heavy minerals following the shortest distance down any reach of a river, at or near bedrock and concentrations, and in accretionary gravel bars or behind obstructions in the river’s flow, the amount of gold in the gravels and sands is greatest in these limited settings in river placers. This is what is generally known about enriched zones in river placers.

Coastal sand deposits are created in a totally different set of hydrodynamic conditions. Coastal sand deposits are made from the repetitive and relentless action of waves on the coastline, winnowing out silt and clay sized sediment delivered by rivers to the coast, washing the sand clean of the “dirt”.

Well when I have “washed” gold bearing alluvial material the gold travels quickly to the bottom of the washing device.

So it is in coastal sand deposits, as demonstrated by this study, the heavy minerals are found in the lower regions of the sand layers, concentrated together by the action of moving water. Sand also moves along coastlines in currents and forms bars that contain gravel conglomerate layers. Beaches have basal conglomerate layers as well.

The other point to be made from this Australian example of coastal sand/mineral deposits is that the inferred size of Mkuvia is not far-fetched. Look at the extent of the Australian deposits, the cover a big chunk of real estate.

This scientific evaluation of heavy minerals in coastal sand deposits provides the clearest models of what Mkuvia might be. Notice that the valuable HMS are not evenly distributed throughout the deposit.

This is why so many placer operations fail, they think all that is needed is to make a discovery, move equipment on to the site and start processing sand. This is risky, here’s why;

Look at the plan-view illustrations in the paper, pick a point on the map, now determine which direction leads to the higher concentrations of HMS? What happens when you don’t have this information and start mining in the opposite direction? Get the idea?

What do you see?

They really hit the mark in this paper IMCO.

Not investment advice. I am not a registered professional geologist, just an educated prospector wanting a home-run. DYODD

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