Blanks for quality control
A blank is material known to contain no gold or other target metals. It is inserted into a sample batch next to ordinary and high-grade samples. If the lab finds metal in a blank, samples are being contaminated during crushing, pulverising or assay.
- OREAS 23b (OREAS) 20 kg
Laboratory test results
Blank batch BL-23 was tested by an independent laboratory: 10 samples, ICP-AES and atomic absorption. Gold is below the detection limit in every sample.
| Element | Range in 10 samples |
|---|---|
| Au | <0.1 g/t |
| Ag | <1 g/t |
| Cd | <2 g/t |
| Se | <5 g/t |
| Te | <5 g/t |
| Cu | 0.012–0.039 % |
| Zn | 0.0047–0.026 % |
| S | 0.016–0.10 % |
Test report No. 1005 dated 11.08.2026. We will send a copy on request.
Coarse and pulp blanks
A coarse blank goes into a bag like a normal sample and passes through the whole prep line: crushing, splitting, pulverising. It shows whether material from high-grade samples carries over through the crusher and pulveriser. A pulp blank is already pulverised and goes straight to the lab, checking the cleanliness of the assay itself.
Where to place blanks in a batch
Place a blank right after samples with visible gold or high grades, where contamination risk is highest. Reserve numbers for blanks in advance, for example on bags printed with sample numbers. See also how many standards to insert.
FAQ
How is a blank different from a reference material?
A reference material contains a known amount of metal and checks assay accuracy. A blank contains none and checks that samples are not contaminated.
Do you have a certified blank?
Yes, for example OREAS 23b. Check its availability in the reference materials table or ask us.
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