What is the preferred approach in order of accomplishment for preliminary aggregate source investigation for a dam feasibility study?

• A. Air photo interpretation, site reconnaissance, geophysical survey, bulk sampling and testing of aggregate samples, write a report
• B. Bulk sampling and testing of aggregate samples, air photo interpretation, site reconnaissance, write a report
• C. Geophysical survey, air photo interpretation, site reconnaissance, bulk sampling and testing
• D. Write a report first, then field work

Answer: (A)

The main idea here is to follow a practical, cost‑effective sequence that first identifies candidates and then confirms their viability with increasingly specific data. Starting with air photo interpretation gives a broad view of the landscape—outcrops, landforms, drainage, old quarries, faults, and other features that hint where aggregate sources might be favorable or problematic. Then doing site reconnaissance adds ground-truth: you can verify what the photos imply, assess accessibility, proximity to the dam site, disturbance risks, and environmental or regulatory constraints that photos alone can’t reveal.

With potential sources highlighted, a geophysical survey can map subsurface conditions without heavy drilling, helping you estimate depth to bedrock, thickness of overburden, and other buried features that affect viability and extraction planning. This step narrows down the areas that warrant more intrusive investigation and saves time and money.

Next, bulk sampling and testing of aggregate samples provides real material data—gradation, strength, durability, and compatibility with the project requirements—so you can confirm that the candidates actually meet the needed specifications before committing to more extensive quarry development. Only after gathering this material data do you compile everything into a report that synthesizes the findings, compares options, and lays out recommended next steps for detailed investigations or quarry permitting.

Starting with bulk sampling or performing a geophysical survey without identifying promising sources would be inefficient and costly, and writing a report before field data is available isn’t practical. This sequence ensures you collect the right information in a logical, economical order.