It is highly recommended to take sand samples from a flowing stream of proppant material, not from a static pile or bag.
Possible sites for taking samples are:
-production line at the manufacturing plant;
-during bulk container loading/unloading, if open system is used;
-conveyor belt when sand is poured into a blender;
-any other place where it is possible to take representative samples from flowing stream of sand.
If there is no possibility to take sample from flowing stream, sample should be taken from proppant to static pile (i.e. loaded bulk truck) or a sack.
There are currently two devices for samples taking, ISO Samples Catcher should be used for obtaining of representative sample of proppant out of the flowing stream, while Sample Thief should be used for taking samples from static proppant pile or sack.
b. Samples taking procedures
Procedure for taking samples from flowing proppant stream:
-The sampling device shall be used with its length perpendicular to the flowing proppant stream;
-The sampler shall be passed at a uniform rate from side to side through the full stream width of proppant moving;
-This shall be done as the material is moving to or from a conveyor belt into a blender, truck, railcar or bulk container;
-Two metric tons of proppant material shall be allowed to flow prior to taking the first sample;
-During sampling, the sampling receptacle shall be passed completely across the moving proppant stream in a brief interval of time so as to take the entire stream with each pass;
-Under no circumstances shall the sampling be allowed to overflow receptacle;
- The length of the 13 mm (0.50 in) slot shall be longer than the thickness of the stream being sampled;
- The volume of the sampler shall be large enough so as to not overflow while cutting through the entire stream.
Procedure for taking samples from static pile or bag:
- Only whole bags are to be used for sampling bagged proppant materials;
- For sampling from the bags, the sample thief shall be inserted into the bag from the top at different angles from different positions for whole pack length;
- When samples are taken from a bulk truck via the top hatch, each manhole shall be sampled. The sample thief shall be inserted with the holes facing down at a 45°-60° angle in three different positions for each manhole, and then turned so that the holes face upward. After tube is filled, withdraw the thief and remove sample;
- In the case of bags weighing up to 50 kg (110 lb.), only whole bags are to be used for sampling bagged proppant materials.
c. Number of samples and samples amount
One sample NLT 2 kg should be taken per every 10 tons of sand produced. So, if 100 tons of sand have been produced, 10 samples NLT 2 kg each should be sent to NTC. Not less than 3 samples should be taken under any circumstances.
d. Labeling and shipment of samples
Each sample should be label with the following information:
- date when sample was taken;
- location where sample was taken;
- sample details (supplier, sample ref, proppant size, etc.);
- name of the employee, who took the sample;