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Logging Method | Field Equipment
Logging Method
The core drill operation obtains foundation data. In order to obtain data of
maximum accuracy, the logger must work closely with the driller, consulting on
changes in materials and coring operations while drilling. The logger must
recognize the reasons for adding extra water, drilling mud, or casing and should
note obstacles to drilling, such as caving, boulders, caverns, and any ground
water. In some cases a core sample cannot be recovered but the logger can watch
the color of the circulation water to see if any change takes place and analyze
the cuttings to see if the material correlates with the previous and subsequent
core samples.
Logging Procedure before Drilling.
| Step |
Action |
| 1 |
Confirm
landowner's permission to enter property if drilling on private
property. |
| 2 |
Stake
desired core drill hole sites and obtain ground elevations. |
| 3 |
Locate any
subsurface power lines, gas lines, telephone cables, sewer pipes, etc. |
| 4 |
Locate
water sources for drilling purposes near the job site, and secure
permission to use them. |
| 5 |
Complete
all steps before the core drill crew and rig arrive. |
Logging Procedure during Drilling.
| Step |
Action |
| 1 |
Lay out
core samples in succession, as obtained, and mark depth by stakes at
each 5-ft. interval. |
| 2 |
Break
open samples to expose fresh surfaces for accurate identification and
classification. |
| 3 |
Identify,
describe, and log the foundation materials, and record all test data. |
| 4 |
Compare
all core samples with previous core samples. |
| 5 |
Prepare
any undisturbed samples for the laboratory by wrapping them in plastic
wrap and labeling them for future identification. |
Logging Procedure after Drilling.
| Step |
Action |
| 1 |
Cover all
uncovered drill holes. |
| 2 |
Pick
up debris and clean up the area in general. |
| 3 |
Repair any
damaged property (fences, lawns, etc.) |
| 4 |
Deliver
any samples retained for testing. |
Occasionally, core holes may need to be grouted or filled with
bentonite pellets if the possibility exists for contaminates to enter from the
surface or from subsurface aquifers. This is especially common in urban areas
with petroleum-contaminated soil.
Field Equipment
The logger needs the following equipment as aids to description
of the materials:
- Pocket knife to cut the samples for testing hardness andexposing fresh surfaces
- Millimeter scale to determine the size of the particles
- Dilute hydrochloric acid to aid in recognizing calcium carbonate materials such as limestone, chalk, or dolomite
- Magnifying glass (10x) to better identify materials by enabling closer inspection
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