What are the students doing, and why is this considered an "capstone" piece?
For the entire year of geology class, the student's have been researching, mapping, and using the geologic map of Colorado. The expectation of each student is that each one of them will be able to use the geologic map to determine subsurface structures and how those structures contribute to produce economic resource deposits.
They will be using the geologic skills that they have learned during the course of the geology classes and applying those skills to locate an orphan well as listed by the state of Colorado and re-use that well that will benefit the local community (for example water source or underground helium storage).
This particular PBL is a capstone, this means that the student's will be using all of the content and skills presented during the geology classes and applying the understanding of these skills to solve the problem.