How do core holes help geologists map an ore body underground?

Core holes are essential tools for geologists to map an ore body underground by providing direct, physical evidence of subsurface conditions. The process involves several key steps:

• Sample Collection: Using a diamond-tipped bit, drills extract intact cylindrical core samples from the earth. These cores are stored in order, allowing geologists to log the specific rock types, mineral presence, and structural features like faults or bedding planes.12
• Laboratory Analysis: Cores are often split lengthwise, with half sent to a laboratory to determine the grade of mineralization—the concentration of valuable minerals—which is critical for assessing economic viability.13
• Visualization: Geologists plot the locations of these holes on plan maps and vertical sections. By combining this data with their knowledge of local geology, they can interpolate the regions between holes to construct a three-dimensional model of the ore body.13
• Geophysical Logging: In addition to physical inspection, instruments may be lowered into the hole to measure properties such as electrical resistivity, density, or natural gamma radiation, further aiding in lithologic identification and formation evaluation.4