Drilling begins on wells

Over the next several months, well-digging crews will be a common sight around Green Valley.

One such crew, their equipment resembling that used to plunge deep into Texas oil fields, has been working for a few weeks near a wash at the corner of La Canada and San Ignacio, drilling the second of 13 planned groundwater monitoring wells.

The work is part of an agreement signed last year between Phelps Dodge, now Freeport-McMoran Copper and Gold, and the Arizona Department of Environmental Quality related to the sulfate plume seeping into the Santa Cruz Aquifer from the Sierrita Mine’s tailing ponds west of town.

Under the agreement, the mine has until September to install the monitoring wells, which will then be checked about every three months for signs of sulfate contamination.

“The purpose of the wells is to help characterize ground water quality and other aquifer characteristics,” said Ned Hall, the Sierrita Mine’s chief environmental engineer.

Next, crews will drill a well near the American Legion post off Duval Mine Road, Hall said. In all, 13 wells will be drilled in six different locations. One already has been completed on La Canada near the old Twin Buttes mine.

Sierrita is still negotiating access to several more locations, Hall added.

He said that homeowners and HOAs near the well sites are being notified in advance of any drilling, and that crews will be working only during daylight hours.

A group of local citizens is monitoring the mine’s compliance with the consent agreement as part of a mandated Community Advisory Group.

Documents related to the process can be viewed by the general public at http://www.phelpsdodge.com/caglibrary

Tim Hull is a freelance writer.