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Wednesday March 26, 2003
1:30 pm to 5:00 pm
This
Workshop was held in conjunction with the Heap
Leach Closure Workshop.
1:30
– 2:15 pm
STEERING
COMMITTEE OF ADTI-MMS | Presentation
|
Virginia
T. McLemore1
and the Steering Committee of the Acid Drainage Technology
Initiative—Metals Mining Sector (ADTI—MMS)
1New Mexico Bureau of Geology and Mineral Resources
(NMBGMR), New Mexico Institute of Mining and Technology,
Socorro, NM, 87801, ginger@gis.nmt.edu
The
Acid Drainage Technology Initiative (ADTI) was created in
1995 by the National Land Reclamation Center, National Mining
Association, Office of Surface Mining, Environmental Protection
Agency, Bureau of Land Management, U. S. Geological Survey,
and Interstate Mining Compact Commission. ADTI’s mandated
task is to identify, evaluate, and develop cost-effective
and practical acid mine drainage (AMD) technologies and
to address other drainage-quality issues related to mining.
The intent of ADTI subsequently has evolved to identify,
evaluate, develop, disseminate information, and promote
understanding about cost effective, environmentally sound
scientific methods and technologies to manage MIW and related
processing materials. In 1999, ADTI was expanded through
the addition of the metal mining sector (MMS) group. ADTI
now addresses MIW drainage quality issues related to metal
mining and related metallurgical operations, including pit
lakes (ADTI-MMS) as well as MIW from coal mines (ADTI-CMS,
coal mining sector), for future and active mines as well
as for historic mines and mining districts.
The
first project undertaken by MMS is the development of a
handbook on best practices and technologies concerning the
sampling, monitoring, prediction, mitigation, and modeling
of drainage from metal mines and related metallurgical materials
based upon current scientific and engineering practices.
The MMS handbook on MIW is a technical document. This handbook
is not intended to be a substitute for regulatory requirements;
instead it is intended to provide tools for solving technical
problems. This handbook addresses all types of mine-drainage
control and treatment methods, including generalized design
and performance criteria. Historic examples and case studies
are included. Design details associated with successful
mining operations and case histories of several mine failures
are provided and research needs and cost effectiveness of
various options are identified and evaluated. The handbook
will enable a user to select technologically effective and
economical sampling and monitoring, prediction, modeling,
mitigation, and mine closure methods suited for particular
geological and environmental situations.
In
the first chapter (Introduction), the basic information
about physical and chemical characteristics of mining, climate,
and environment are provided. The remaining five chapters
include sampling and monitoring (chapter 2), prediction
(chapter 3), mitigation (chapter 4), modeling of MIW (chapter
5), and pit lakes (chapter 6).
Other
projects undertaken by MMS include:
• RAMS Database work
• RAMS Engineering Handbook
• the MMS group presented a training course; Bureau
of Land Management (BLM) Course 3000- 47 Acid Rock Drainage,
Prediction and Treatment
• Coordination and support for corporate research.(Molycorp)
• INAP Coordination.
• Incorporation as a formal Non-Profit Corporation.
The ADTI-MMS website (http://www.unr.edu/mines/adti)
2:15
– 2:45 pm
SAMPLING
AND MONITORING COMMITTEE OF ADTI-MMS | Presentation
|
Virginia
T. McLemore1, Carol
C. Russell2, and the
Sampling and Monitoring Committee of the Acid Drainage Technology
Initiative—Metals Mining Sector (ADTI—MMS)
1New Mexico Bureau of Geology
and Mineral Resources (NMBGMR), New Mexico Institute of
Mining and Technology, Socorro, NM, 87801, ginger@gis.nmt.edu
2U. S. Environmental Protection
Agency, 999 18th Street, Denver, Colorado 80202, russell.carol@epa.gov
The
Metals Mining Sector of the Acid Drainage Technology Initiative
(ADTI-MMS) addresses mining impacted waters (MIW) drainage-quality
issues related to metal mining and related metallurgical
operations, for future and active mines as well as for historical
mines and mining districts. One of the first projects of
ADTI-MMS is to develop a handbook describing the best documented
science and methodologies for sampling, monitoring, prediction,
mitigation, and modeling of drainage from metal mines and
related metallurgical materials based upon current scientific
and engineering practices. The sampling and monitoring committee
is charged with preparing the sampling and monitoring chapter.
This chapter reviews basic philosophical and scientific
features of sampling and monitoring. While focusing mostly
on sampling of ground and surface water, soils, and rocks,
other media including air and biological organisms also
are considered in this chapter. The purpose of this chapter
is to describe the philosophy of sampling and monitoring,
discuss some of the most commonly used sampling and monitoring
techniques, provide cost-effectiveness information about
various techniques, offer guidance about which techniques
are most suitable, and critique the strengths and shortcomings
of various approaches or techniques. Workshops are planned
to disseminate the information in this chapter.
2:45
– 3:15 pm
ADTI
MODELING COMMITTEE – STATUS REPORT | Presentation
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Edward
M. Trujillo, Chair ADTI-MMS Modeling Committee
Mining
companies, consultants, and federal and state land-managing
agencies are challenged with making environmentally-sound
decisions on how to best manage millions of tons of mine
waste from abandoned, existing, and future metal-mining
activities without adversely impacting existing surface
and groundwater quality. Mine-waste management decisions
are largely based on the predicted quality of drainage from
the mine waste. While suites of laboratory-predictive tests
and their results are commonly used by industry and reviewed
by mining companies and land-managing agencies to help forecast
mine-waste drainage quality, no consensus exists regarding
how well these tests predict future drainage quality in
the field. Because of the complexity of the problem and
the uncertainty of predictive-test accuracy, mining companies
and land-managing agencies are concerned that the prospect
of having contaminated drainage develop 25 to 50 years in
the future from mine-waste is a real possibility. To avoid
such a scenario, mining companies, consultants and federal
and state agencies need a single resource outlining the
current state-of-the-art in predictive models, an understanding
of their application and interpretation, and an organized
compilation of the source and cost of these models. These
aspects are essential for making scientifically based decisions
on mine waste management and are the focus of the ADTI modeling
committee.
The
specific objectives for the ADTI-MMS modeling committee
are to conduct a literature survey of existing predictive
models for acid rock drainage systems, compile the results
of the survey and write two workbooks or guidance manuals
on modeling – one on geochemical modeling and another
on geochemical modeling coupled with transport or flow.
This talk will give an overview of modeling and the status
of the ADTI-MMS modeling committee.
3:15
– 3:30 Break
3:30
– 4:00 pm
MINE
ROCK PILE EROSION AND STABILITY EVALUATIONS AT MOLYCORP'S
QUESTA MINE, NEW MEXICO | Presentation
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Dennis L. Turner Sr. Programs Consultant
(602) 771-4501
ADEQ, 1110 W. Washington St., MC5415B-3, Phoenix, AZ 85007
Molycorp
began mining molybdenum and producing concentrate at Questa
in 1919, first by mining the high-grade lode veins, followed
by an open pit operation beginning in 1965 and then by underground
methods beginning in 1983, which continues today at about
2700 TPD. The open pit operations ceased in 1981, leaving
9 mine waste rock piles, some of which are 1600 ft high.
Mine rock piles from the open pit operation were created
as valley fills followed by end dumping. Over time, since
surface mining ceased, concern has grown about the long-term
weathering effects of the mine rock piles and resultant
drainage and slope stability issues. Molycorp has requested
research proposals from four university-based research teams
to investigate the potential effect of physical and chemical
weathering within the span of 100 years and over geologic
time (much greater than 100 years). The project's goal is
to develop a model that assesses the risk of failure of
the rock piles, based on their physical, chemical, mineralogical
and weathering characteristics.
4:00
– 4:30
PROGRESS
OF BLM-FUNDED ACID MINE DRAINAGE RESEARCH
W.
W. White III1 , Kim A. Lapakko2
, and Edward M. Trujillo3
The
environmentally sound management of abandoned, existing,
and future metal mine wastes on public lands has been identified
as the most difficult and costly reclamation problem facing
federal and state land-managing agencies. Drainage-quality
prediction is essential to environmentally sound mine-waste
management. The U.S. Bureau of Land Management (BLM), in
association with the Minnesota Department of Natural Resources
Division of Lands and Minerals (MN DNR) and University of
Utah Chemical and Fuels Engineering Department (University),
continued sponsorship of research on predictive modeling
of contaminated drainage from metal-mine waste after the
U.S. Bureau of Mines closed.
A
well-defined kinetic test protocol was developed and approved
as an ASTM method with funding from the USBM and the BLM.
BLM-sponsored research showed that the ASTM humidity-cell
protocol produced highly reproducible drainage quality,
within and among laboratories, on four waste-rock lithologies
(MN DNR). A simplified humidity-cell method produced results
similar to those from the ASTM protocol with comparable
intralaboratory replication. Mine-waste characterization
and accelerated-weathering (humidity cell tests ranging
from 20 to 278 weeks) were conducted on 63 samples from
eight different mine-waste lithologies (MN DNR). For three
lithologies with at least moderate amounts of calcium and
magnesium carbonates, 24 to 60 percent of the neutralizing
carbonates were available in samples with neutralization
potentials of 21 to 42 g CaCO3 (kg rock)-1. Acid production
thresholds were identified based on the sulfur content of
two mine-waste lithologies with very low calcium and magnesium
carbonate contents. Drainage pH values less than 4.5 were
produced by Duluth Complex samples with S > 0.41% and
field test piles yielded drainage pH values similar to laboratory
values for samples of similar sulfur content. Drainage pH
values less than 4.5 were also produced by Archean greenstone
samples with S > 0.2%. Field rates of chemical release
from Duluth Complex and Archean greenstone rocks typically
ranged from 10 to 45 percent of those for laboratory samples
of similar sulfur content.
The
University’s laboratory model demonstrated reasonable
agreement between modeled output and actual pH, sulfate,
and calcium concentrations from weekly humidity-cell drainage
produced from accelerated weathering of five different waste-rock
lithologies. The field model linked governing geochemical
reactions to transport phenomena in porous media and produced
concentration profiles for multiple species in a simulated
symmetrical test pile.
Results
from the BLM-sponsored research are published in 5 peer-reviewed
journal papers, 2 M.S. theses, and 19 contract reports.
1
Physical Scientist, U.S. Bureau of Land Management,
Salt Lake Field Office
2 Principal Engineer, Minnesota
Dept. of Natural Resources, Lands and Minerals Division
3 Associate Professor, University
of Utah, Chemical and Fuels Engineering Dept.
4:30
– 5:00
Pit
Lake Committee Report. |Presentation
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