I was talking with my colleague Terry Stransky from Terracon about doing sampling and testing for sand deposits.
He sent back some great info, especially as it relates to evaluating sand for traditional sand and gravel operations.
Take it away, Terry!
“You should note that for initial source evaluation we typically do one boring for each ten acres. We also recommend doing borings, not surface sampling, to the anticipated depth of the deposit, or the presumed depth of mining, as sand and gravel deposits can be notoriously inhomogeneous. Laboratory testing, even for just sieve analysis, will be dependent on what the borings show.
Typically before we do any exploration program, whether for sand/gravel operations or for stone quarries, we want to look at available geological information: bedrock geology, glacial geology and other surface geologic maps, topographic maps, groundwater resource maps and aerial photographs. If there are already pre-existing boring logs for a site or in a general geographic area, we like to look at those as well.
Once we have reviewed those, we need to look at things like how large the site is acreage-wise, how thick the deposits are (based on the reviewed information described above), depth to groundwater, which may determine how much of the deposit is economically minable etc.
The “rule-of-thumb” of 1 boring per 10 acres is just that. It is usually a good starting point , and results of the initial borings may help define further exploration targets. Typically, we don’t sample every foot of each boring at this stage. Depending on the anticipated thickness of the deposit and depth to groundwater, we might sample every 5 feet or at a change in lithology of the deposit.
Laboratory analyses might include grain size distribution curves, limited petrographic examination (especially for roundness and spehericity if we’re talking about frac sand), full petrographic examinations if we’re talking about a potential concrete aggregate source, etc.”
Here’s Terry’s info, if you would like to talk with him on your evaluating sand, especially for sand and gravel quarry use:
Terry Stransky, PG
Terracon Consultants, Inc