Bulkprøver

Bulkprøver, or bulk samples, are large, composite samples taken to characterize the average properties of a mineralized body or material. They are designed to capture the variability and behavior of a material as it would occur in processing, rather than the more limited insight provided by small-diameter drill samples or core.

They are commonly used in mineral exploration, mine feasibility studies, and metallurgical testing. Bulkprøver help determine ore grade and variability, assess recoveries in processing plants, and inform mine planning and economic evaluations. In environmental and industrial contexts, bulk samples may be collected to assess contamination, material quality, or feedstock characteristics.

Collection and design principles focus on representativity and practicality. Bulkprøver may be collected by channel sampling along outcrops or trenches, from face samples in underground workings, or by compiling large tonnages from a defined volume of ore or waste. The size of a bulk sample can range from tens of kilograms to several tonnes, and larger samples are used when the goal is to simulate processing streams or reconcile production. A well-designed bulk sampling program accounts for spatial variability, sampling bias, and logistical constraints.

Analysis and quality control involve homogenizing the bulk sample through crushing and grinding, followed by sub-sampling for laboratory assays. Common analytical methods include fire assay for precious metals, and ICP-OES or ICP-MS for base and trace elements. QA/QC measures—duplicates, blanks, certified reference materials, and process blanks—help assess bias and precision. Final interpretations integrate analytical results with geological and metallurgical understanding, recognizing the limitations inherent in representativity and scale.