Submitted by Nancy Freeman
Executive Director,
Groundwater Awareness League, Inc.
P. O. Box 934
Green Valley, AZ 85622

January 19, 2012

Ms. Blaine, I have sent you info on the degeneration of the groundwater in Green Valley in regard to TENORM and sulfuric acid spills at the Sierrita mine. There is little surface water in their area, so I have not had as much experience with it. Of course, the chemical spills and milling and tailing toxic heavy metals are delivered to the surface and will impact stormwater.

First, there is a question of the validity of company's surface water rights:

Questa Spring, Barrel Canyon, McCleary Canyon, Wasp Canyon, Rosemont Spring, and two unnamed springs. See ADWR docs:

Toxic chemicals are used in the Flotation Process to separate the copper and molybdenum out of the milled powder. Flotation is the major extraction process because of the poor quality of the copper at the Rosemont site. Some chemicals produce bubbles that that the copper adheres to while the other metals fall to the bottom. These chemicals are hydrocarbons with complex configurations, but some are as simple as kerosene. It is claimed that the volatile organics used in the Flotation Process do not go into the slurry that goes into the tailings impoundment because they are filtered out before the slurry goes to the impoundment. This is not a sound analysis.

1) Filtration is not a treatment technology for volatile organics. Treatment is pushing air the solution which releases the volatile chemicals into the air [Employees are protected by OSHA regulations].

2) Some are amine compounds that break down into nitrates, so the presence of nitrates in the groundwater is an indicator of travel of these compounds, which can be very mobile in an oxygen solution, i.e., H 2 O.

Some of the Chemicals Used in Flotation Process

In addition, Super powerful explosives—ANFO (ammonium nitrate and fuel oil)—used to blast the rock in the pit leaves traces of nitrates in the blasted rock and the flotation solution.

Although the company predicts large quantities of silver, the processing method of the silver in the oxide deposit is not given in the MPO. In some cases, cyanide is used in the heap leach process for extracting silver.

Another impact to surface and tailings is the extra powerful explosives—ANFO (ammonium nitrate and fuel oil)—used to blast the rock in the pit. Traces of nitrates are left in the blasted rock and the flotation solution, and the slurry delivered to the impoundments.

There is continual degradation of the surface soil by truck maintenance, washing and gasoline stations. CalPortland Cement operations on I-10 in Tucson has had several ADEQ violations in their truck area, such as gasoline spills and grease that comes off the trucks during maintenance and washing.

None of the alternatives of the tailings/waste piles will work for the same reasons:

1) The terrain is very hilly and composed of both hard rock and fractured rock. The fractured rock is what enabled the metals to form. These are not hillocks of top soil like the Rosemont mine people seem to think. How are they going to spread tailings and waste rock on 45 degree slopes? How are they going to crunch up all the existing hillocks?

2) Thousands of mature trees (33,000 according to my count) will be destroyed, while groups all over the planet are planting trees for the sake of clean water and clean air. The company plans to cut down, then chop/chip the trees, but how will the roots of 150 old oaks be dealt with? Will they be left to rot and contaminate the water supply?

3) Last and most important impact will is the stormwater. An on-going project for restoration means an on-going soil disturbance. Stormwater in the summer (and occasionally in the winter) will make it difficult to keep the piles in place. In short, the stormwater will pick up toxic heavy metals and processing chemicals from the piles, as well as large amounts of sediment to sweep down stream.

I have helped residents in Sahuarita Heights, the rural, mobile home area near Sahuarita (where the water supply wells will be) with flooding due to soil/wash disturbance by a new development at Country Club and San Rita. This flood plain is on the west side of the Santa Ritas; however, the data (since I can find none for the east side) should be useful to you in getting an idea of the flood conditions off the same mountains on eastern watershed. I've been in the Rosemont Junction area after the summer rains, and I expect that the flow conditions are similar. Further, at the public hearing in Sahuarita on January 14, a gentleman from Greaterville spoke of the flooding that already exists in the Greaterville region.

A study was done by Pima County of the region at Sahuarita Road and Santa Rita Road with maps and photos. This area was impacted by the land disturbance of a housing development. The downstream residents were actually getting water in their homes. As the report shows, there are few remedies after the damage has been done.

The northwestern watershed of the Santa Ritas was documented in the Lee Moore Wash Study, 2009.

The study shows that the flow levels increase from 1' to 2' to 2' to 5' at Country Club and Santa Rita Rd. the location of the new development.

The study shows a flow velocity map. However, I cannot discern the units the flow rates are given in. I'm sure you can get the info from the Pima County Flood Control Dept. Personnel was not available when I inquired.

A good example of the stormwater flow—even in flatter land—is the floods in Sahuarita last September, 2011. The unusual aspect was the water that jumped an 8' cement embankment carrying an immense sediment load. Thick mud was deposited in the homes and on the roads. Prison crews cleaned it from the streets with pressure hoses and industrial brooms. There was some soil disturbance for construction up stream and new headcuts into the wash from other construction, but it's hard to imagine where the volume of sediment came from. A resident reported that in July of the same year, the water in the wash was brown and nearly reaching the top of the 8' embankment