Tailing Dam at Tyrone Mine, Tyrone NM

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Abstract

Valuable reclaimed areas are being threatened by high velocity runoff near the tailing dams of the Tyrone Mine in southwestern New Mexico.  Therefore the goal of this project was to identify and design the best streambank stabilization method to prevent headcutting and erosion into tailing repositories near the confluence of the Mangas and Wind Canyon washes.

Several options were identified, and the use of a decision matrix helped determine that the installation of bendway weirs, in combination with bank armoring, would be the most effective solution. Hydraulic modeling of Wind Canyon showed that bendway weirs deflect flows away, while decreasing velocities, from the headcut bank areas. 

Many aspects associated with the bendway weir indicate the structure to be a viable alternative to armoring the entire channel in order to control migration and bank erosion.  The addition of riprap along the affected bank would further aid in the protection of the reclamation activities.  Other design alternatives included tire mattresses, rock triangles, longitudinal stone toe, and riprap alone.

History & Objective

The objective of this project is to design a streambank stabilization method to prevent headcutting and protect from erosion at the confluence of two waterways. Mangas Creek, located in southwest New Mexico, runs through property owned by Freeport McMoRan (formerly Phelps Dodge) near the Tyrone Mine. Several remediated tailing ponds are located near the confluence of Mangas Creek and Wind Canyon, and insufficient erosion control is currently jeopardizing these sites. It is in the interest of Freeport McMoRan that this solution captures all aspects of the above goal. The west bank of Wind Canyon is flat with a gradient less than 1%, while the east bank is steeper.

Mangas Valley Road and the main water pipeline for the mine are located on the east bank.  In 1980, tailing was deposited by erosion caused by high flows in Mangas Creek, and mine tailings was removed from the wash. Recent high flows in Wind Canyon have also cut into a road, which led to a main water pipeline for the mine to be exposed. A drop structure was then placed downstream of the cut to help prevent future headcutting, but more action needs to be taken to stabilize the streambank. The main focus of this project will be to stabilize the area of Wind Canyon between the road and the confluence of Mangas Creek.

Erosion Below Drop Structure In Wind Canyon

Site of Increased Headcutting and Erosion  Just Below Drop Structure in Wind Canyon