What is Box Sampling?
Box Sampling is a soil and rock sampling method carried out by manually excavating a square or rectangular pit of a specific size. This technique is primarily used to collect bulk samples or disturbed samples from a targeted geological layer.
Key Characteristics of the Box Sampling Method
Applied at the surface or shallow depth (generally less than 1.5 meters).
The excavation shape is a square or rectangular box.
Samples can include soil, sand, laterite, weathered rock, or exposed hard rock outcrops.
Does not produce undisturbed samples, since the excavation process alters the natural structure of the material.
👉 Related article: Soil Layer Measurement Using Geotechnical Hand Auger
Steps of the Box Sampling Method
1. Site Selection and Objective
Identify the location using geological maps or results from preliminary surveys.
Ensure the site is safe for manual excavation.
Define the box dimensions and depth required (e.g., 30×30×30 cm or 50×50×50 cm).
2. Preparation of Tools and Equipment
Excavation tools: hoe, shovel, crowbar, geological hammer.
Measuring & documentation tools: tape measure, notebook, GPS, camera.
Sampling materials: plastic or cloth bags, labels, markers, buckets.
3. Excavation of the Box Pit
Excavate a square-shaped pit with predetermined dimensions.
Standard sizes can be adjusted based on project requirements.
Depth is determined to reach the targeted soil horizon or geological layer.
4. Sample Collection
Carefully collect material from the box to avoid contamination.
Place samples into bags and label them with key details such as:
Location code
Depth
Sampling date
Material type
If needed, collect sub-samples for laboratory testing (e.g., moisture content, specific gravity, grain size distribution).
5. Recording and Documentation
Record complete site conditions: lithology description, soil/rock color, and structural characteristics.
Take photos before and after sampling.
Mark the site with GPS coordinates for future reference.
6. Site Backfilling and Reclamation
Refill the pit with the excavated material.
Restore the area to minimize environmental impact and ensure safety.
Benefits and Outcomes of Box Sampling
Provides direct visual information about the characteristics of soil or rock layers.
Enables representative sampling for laboratory analysis, including:
Metal content testing
Chemical analysis
Moisture content testing
Grain size distribution analysis
Offers preliminary geological data useful for exploration, construction, and scientific research
Box Sampling is a simple yet effective field method for soil and rock sampling, especially at shallow depths. When performed with proper technique and thorough documentation, it provides valuable geological information that supports civil engineering, mining, and environmental projects.