WATERSHED STRATEGY FOR CLEAN-UP OF ABANDONED MINE LANDS

• Jurisdiction: United States

Cleaning up the Public Domain: The Next Frontier
(Mar 1996)
CHAPTER 1B
WATERSHED STRATEGY FOR CLEAN-UP OF ABANDONED MINE LANDS
Robert H. Robinson
Bureau of Land Management Colorado State Office
Lakewood, Colorado

INTRODUCTION

Estimates of the number of abandoned mine sites vary widely from 200,000 to more than 500,000 sites. These sites occur in mining districts scattered primarily throughout the western U.S. Abandoned mine lands (AML) have been a major source of water quality degradation and environmental pollution for over a century. In Colorado, for example, there are over 1,200 miles of streams impaired by heavy metal pollution¹ . Many of the larger hazardous waste mine sites with viable responsible parties are being remediated under the Superfund program. What remains are numerous small abandoned sites that individually have small impacts, but cumulatively degrade our streams and inhibit aquatic life.

The Federal land management bureaus in the Department of the Interior (DOI) and the US Department of Agriculture (USDA) have announced an initiative² that will expedite the cleanup of AMLs on Federal public lands. The initiative is supported by Governors Roy Romer³ and Marc Racicot⁴ , and the Western Governors' Association⁵ . A speech⁶ (copy attached) by Deputy Assistant Secretary Sylvia Baca further describes the clean-up initiative and its background.

This paper briefly outlines the technical aspects of the watershed strategy.

THE CHALLENGE

The AML challenge is devising a cost effective strategy to clean-up polluted discharge given the large numbers of AMLs, inefficiencies in the traditional site-by-site remediation approach, and the lack of funding. The lack of funding will be discussed further by Bob Higgins later in this session.

Requiring the usual site-by-site clean-up approach would overwhelm resources of land owners and land management agencies.

Firstly, the cost of preparing site plans for all AML sites would be a tremendous waste of resources and funds because the AMLs that are affecting water quality are expected to be a small subset of all AMLs.

For example, consider a watershed with perhaps 300 AML sites and a typical cost of $10,000 to $30,000 per site for a site clean-up plan. Site plans include characterization of baseline conditions, mine wastes, and discharges, and design and engineering of clean-up, and monitoring. The total cost of site plans for all 300 sites is $3,000,000 using the $10,000 per site lower end of the cost range. This cost is incurred before you turn a spade of dirt for actual clean-up. Alternatively, less than ten percent of the sites typically are responsible for polluting a watershed. Most of the sites (90 per cent in this example) have no more than intermittent discharge from surface run-on and run-off during snowmelt or thunderstorms when pollutant concentrations are very low and pollutant concentrations are diluted by the large water volume of an event. If

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there is a way of identifying the ten percent bad actors early on before site planning, the total cost for site plans would be $300,000, a saving of $2,700,000 over the site-by-site approach.

Secondly, there is a high likelihood that tail-pipe (effluent) standards on polluted AML discharges are not necessary in order to gain the objective of meeting water quality goals. For AML discharges, two basic control technologies are available — one is active mechanical treatment plants and the other is more passive waste management practices.

Active mechanical treatment plants can be designed to meet tail-pipe standards. However, these plants are expensive and require daily operation and maintenance. They would require operation indefinitely for as long as the AML discharges continue.

Alternatively, passive waste management practices could be implemented such as mine bulkheads, diversion structures, filtration devices, detention/retention devices, soil amendments, covers and liners, regrading, relocation, revegetation, and stream modifications. These practices cannot individually meet tail-pipe standards; however, the cumulative effect of implementing these practices at a number of sites could bring water quality in line with goals. The advantage is low construction cost and low annual maintenance.

A...