Replies to post #43 on Barker Minerals Ltd (BML)

[echarters]

Figures are a little screwed here. Total weight should be 2930.08 pounds. The tonnage factor for the ore at 165.43 pounds per cubic foot is 2000/165.43 = 12.089.

Also voids in a sand are generally figured at 40%. This varies.

In clay you are right. Avoid it if possible in contruction as it
is treacherous to build on and hard to work with. Costs double easily in excavation. Terrible stuff.

It is very common in placer areas as it forms an impermeable bed of concentration or a psuedo-bedrock base. It is common to find loose blue clay in some BC placer areas. The loose stuff which is really glacial till, is not much of a problem, but too much slime clay has been known to act as a flotation agent for gold. You can use surfactants to increase wetting but they clog up sluices. Hi-G machines that use centrigal force are much less affected by these problems.

Then Ross Box was developed to combat clay in placers. Trommels and water sprays have also been found effective.

EC<:-}


EC<:-}

[marcos]

Ok, this makes sense .... a few too many numbers for my comfort, perhaps -g- ... i just think of it in terms of comparison with water, which is of course the standard specific gravity figure as well, a/k/a the number of tonnes per cubic metre, or the number of kilos per litre .... water being by definition 1.0 tonne per cubic metre, and 1.0 kilo per litre

'Rock volume will expand 50% to include voids, when broken.'

I believe that, and suspect it might be more at times, near double even ...... one of my experiences with shot rock was spreading it while building logging road, and trying to make each load of it go as far as possible, while still making a road that would hold up a loaded truck .... on rare places where the subgrade was firm, you could run the D8 back and forth after spreading shot rock, and reduce its volume by near half, i swear ..... of course where the subgrade was not firm, you needed more because the first lift of it sunk out of sight