1.   After constructing two wells, YPF decided to renegotiate the agreement.

2.   State authorities still are investigating whether the contamination comes from leaking livestock lagoons, fertilizer or poorly constructed shallow wells.

3.   The rig is designed to reduce the time required to construct wells and to minimize environmental risk, Schlumberger said.

4.   Tree wells are constructed out of timbers or brick around the trunk of a tree so that soil can be added to the natural grade.

5.   Unfortunately, constructing a well without considering the real needs of the tree will often lead to the death of the tree in a few years.

6.   Wells are now constructed in tight ranks on small gravel pads, branching out underground instead of peppering the surface over a broad area.

7.   He said the well was constructed by a mining engineering company which took about a week to complete the job.

8.   How was the well constructed?

9.   The wells are constructed using a combination of rocks, sand and palm fiber.