There are some important things to remember when sampling and testing across a sand deposit, especially if you are considering the frac sand market.
If you are considering doing such a project, you might want to consider the following process.
1. Map out the sand deposit
Your mapping does not need to be perfect, but this will help your sampling techniques, and is good engineering practice. Just print out — on large paper if possible — a Google map of the property and sand deposit in question.
Then, in red marker, outline the sand deposit on the map. Then, select a few spots around the deposit to sample. This may be very dependent on your budget. For instance, we have worked with clients who can afford to samples dozens of times, and other clients can only sample 3 times from a deposit,
2. Sample according to the map, label the samples
Now, head out into the field and use the map to sample. If gathering surface samples, make sure that you dig down past any surface contamination, and into the deposit, so that your sample is representative of the deposit at that sampling location. Take at least 5 pounds (3 kg) per sample. At least that much.
For some projects, it may make sense to take 3 samples in an area, then combine those into 1 composite sample for testing. This is a hypothetical, and might not apply to your specific project.
Important! – when sampling, label the sample with a descriptive term (or even better, GPS coordinates!) from your deposit map. This will help later on, should the samples vary in quality. You will know exactly where each sample came from. And using the map you made, you can see how the quality varies across the deposit.
3. Arrange testing with a laboratory
At the very least, you will want a sieve analysis, and initial crushing done on fractions within the sample.
One of the most objective tests that you can run is first a sieve analysis, and then crush testing on the various fractions in the sample. For example, the sieve analysis might show that 40/70 and 70/140 (also known as 100 mesh sand) are very prominent in the sample. In this case, it might make sense to do an initial crush test on both those sizes at 5K, to see how they crush. Or, just crush right away to K value.
You should be able to find a lab that can work with you and your budget to come up with some testing options. With some labs, you can call ahead of time, and they should be able to provide you with an estimate for number of samples and a variety of testing done with those samples.
In our lab, once you get above 5 samples, we can start to really show you some “package deal” savings.