What marks the conclusion of the drilling process at a site?

The conclusion of the drilling process at a site is marked by the date that drilling is completed. This signifies that the primary objective of the drilling, which is to reach the targeted depth or formation, has been achieved. It is a definitive point in the drilling timeline where the well is established, and further operations can begin, such as well development or the installation of necessary equipment.

While other options involve important post-drilling activities, they do not signify the end of the actual drilling process. For instance, well development is crucial for enhancing the well's performance but occurs after drilling is finished. Similarly, the installation of the discharge head and initiation of groundwater testing are subsequent steps that take place after drilling has concluded. Thus, the date that drilling is completed accurately reflects the conclusion of the drilling process itself.