New Mexico State University - AML PROJECT ......AML PROJECT: INVENTORY AND CHARACTERIZATION OF INACTIVE/ABANDONED MINE (AML) FEATURES IN NEW MEXICO Virginia T. McLemore New Mexico

AML PROJECT: INVENTORY AND CHARACTERIZATION OF INACTIVE/ABANDONED MINE

(AML) FEATURES IN NEW MEXICO

Virginia T. McLemoreNew Mexico Bureau of Geology and Mineral Resources, New Mexico Tech, Socorro, NM

ACKNOWLEDGEMENTS Funding

• New Mexico Bureau of Geology and Mineral Resources (NMBGMR)• Energy Minerals and Natural Resources Department and the U.S.

Department of the Interior, Office of Surface Mining and Reclamation(OSMRE)

• Mineral Engineering Department of NMIMT• New Mexico Geological Society• New Mexico EPSCoR (funded by the National Science Foundation

award #IIA-1301346))

Numerous M.S. theses Professional staff and many students who worked on these

projects (Nelia Dunbar, Lynn Heizler, John Asafo-Akowuah, William Zutah, Marcus Silva, John Durica, Bonnie Durica, Joseph Shackleford, Navid Mojtabai, Bonnie Frey)

Is there a potential Gold King disaster in New Mexico?

What is the state of AML/inactive/legacy mines in New Mexico?

AML=Abandoned Mine Lands

Lands that were mined and left unreclaimed where no individual or company has reclamation responsibility. These may consist of excavations, either caved in or sealed, that have been deserted and where further mining is not intended. Also called inactive, legacy and orphaned mines.

What are AML?

Waste rock pile

Most AML projects focused on physical hazards

Gold King spill is a game changer in how government agencies handle remediation of AML

Many state and federal agencies and mining companies have mitigated many of the physical safety hazards of AML, but very few of these reclamation efforts have examined the long-term environmental effects, unless the NMED identified them as a source of contamination of water sources

There is still potential for environmental effects long after remediation of the physical hazards Terrero (Pecos), Jackpile and Questa mines

The NMBGMR in cooperation with the Mineral Engineering Department at New Mexico Tech and the NM AML program is conducting research on legacy mine features in New Mexico

WHAT IS BEING DONE?

Superfund established in 1980 Comprehensive Environmental Response,

Compensation, and Liability Act of 1980 (CERCLA) Designed to clean up sites contaminated with

hazardous substances and pollutants OSM (Office of Surface Mining) was established

with the passage of the Surface Mining Control and Reclamation Act (SMCRA) of 1977 (mostly coal) Collection of reclamation fees from current coal

mining operators and awarding reclamation grants to states and tribes that have current coal production to cleanup all mine sites

Mining companies today have major reclamation projects

Tyrone, tailings NM

SUPERFUND SITES

There are 19 active superfund sites in NM 6 are mining sites

Chevron, Inc. (formerly Molycorp) Questa mine, Red River (molybdenum mine and mill)

Cimarron Mining Corp. (Carrizozo, gold mills that used cyanide, completed in 1992, but monitoring is ongoing)

Cleveland mill (Silver City, gold, silver, copper mine and mill, completed in 2001)

Homestake Mining Co. mill, Grants uranium districtJackpile-Paquate mine, Grants uranium districtUnited Nuclear Corp., Grants uranium district

Homestake mill, Grants

OUTLINE• Potential

problems• Purpose of

NMBGMR AML program

• Methods• Lessons learned• Summary Lordsburg mining district,

Hidalgo County

POSTER IN THE LOBBY

WHAT ARE POTENTIAL IMPACTS ASSOCIATED WITH AML?

Most mines, waste rock piles, tailings, and heap leach facilities are safe and have remained stable with little or no environmental impacts.

But physical hazards are common in many districts.

There has been a major tailings dam or rock pile failure or unintended water release every year somewhere in the world over the last few decades and a few in NM.

Acid rock drainage and contamination by metals and other constituents is a problem at some sites in NM.

CHURCH ROCK TAILINGS SPILL, NM

1,100 tons of radioactive tailings and 94 million gallons of acidic wastewater were released to the Puerco River in the spill

Spill fluids traveled at least 80 miles downstream in the Puerco River

The 20-foot breach in the tailings dam formed around 5:30 am on the

morning of July 16, 1979.

GOLD QUARRY, NEVADA

In February 2005, one of Newmont's 10-million ton waste rock dumps at the Gold Quarry mine, collapsed and slid across Nevada Highway 766. Possible cause by placing clay on top of other rock material, then weaken by excessive rain water.

Hillsboro

Jicarilla

Pinos Altos

Hillsboro

EROSION AND SEDIMENTATION

More than $68 billion worth of minerals have been produced from New Mexico since 1804

245 mining districts 28 coal fields

BUT WE DO NOT KNOW HOW MANY TOTAL INACTIVE OR AML MINE SITES

ARE IN NM (best guess >30,000 mine features)

Mines in New Mexico (from the New Mexico Mines Database and BLM data, includes aggregate pits)

NM AML PROGRAM (NM MINING AND MINERALS DIVISION)

Started in 1981 Safeguarded over 2,300 mine openings In about 250 separate construction

projects Including coal gob (waste material)

reclamation Funded by coal mine tax

OSMRE Office of Surface Mining and Reclamation

Swastika coal mine, Raton (AML photo)

https://amlis.osmre.gov/Map.aspx

NM AML sites

OTHER CLOSURE EFFORTS

Mining companies USFS and USBLM

PURPOSE OF NMBGMR AML PROGRAM

Develop a better procedure to inventory and characterize legacy, inactive or abandoned mine features in New Mexico that addresses potential environmental issues and potential impacts to water and human health

Sampling at Lucky Don U mine and waste rock pile in Rosedale district

PURPOSE OF NMBGMR AML PROGRAM

Summit mine, Steeple Rock district, Grant

County

Provide data on districts, mines, and mills in New Mexico

– Help plan and assess reclamation procedures

– Determine background concentrations

– Understand geologic processes– Compare trace-element

concentrations in mined versus undisturbed areas

– Provide background data that can assist with the planning of future mining operations

Purpose—continuedTo make informed decisions about

– Economic impacts– Resource development and

management (mineral resource potential)

– Impacts on water supplies – Impacts on land use – Environmental impacts (including

potential sources of AD [acid drainage] or other MIW [mine influenced waters])

– Physical hazard assessment and remediation

Adit, Jicarilla Mountains,

Lincoln County

METHODS Inventory the mines

History of the site (production, commodities, mine methods, processing facilities)

Characterization Paste pH, mineralogy, chemistry, etc.

Prioritize mine features Detailed characterization of high priority

sites Detailed mineralogy and chemistry ABA/NAG tests Particle size analyses Shear tests

SOIL PETROGRAPHY–FIRST STEP IN DETERMINING MINERALOGY

2 mm

Pyrite characterization Evaluate the

distribution, form, size, amount, surface area of pyrite in the rock piles

1

2

3

4

5

6

7

8

9

0.01 0.1 1 10 100 1000

NAG

pH

NPR

ARD Classification Plot

UNCERTAIN

NON-ACID FORMING

POTENTIAL ACID

FORMINGUNCERTAIN

Little Davie and Lucky Don Rosedale

Jeter Jicarilla

Acid Rock Drainage (ARD) classification plot of composite waste rock pile samplesfrom various districts. Little Davie, Lucky Don (Socorro district), Jeter (LadronMountains district), and Rosedale district samples are in Socorro County. Jicarilladistrict is in Lincoln County.

SELECTED PAST AND ONGOING PROJECTS

New Mexico Mines Database Questa weathering study—examine the effects

of weathering on the stability of the Questa mine waste rock piles

Geochemistry of legacy mines in Socorro and Sierra Counties

Pecos River project—examine stream sediments and water above and below a volcanic massive sulfide mine and mill

EPSCoR project—examine the mobility of uranium in the Grants district

LESSONS LEARNED

CAUSES OF UNDESIRABLE IMPACTS

Too much water Results in weathering of the rock and soil Can creates unstable features and acid drainage

Need to control water into the mine workings, rock pile, tailings, heap leach, and foundation materials

Poor foundation conditions Weak materials like clay, altered, fractured rock

Poor understanding of effects of weathering on the degradation of materials

Every site is different and must be specifically characterized

HOW CAN THESE IMPACTS BE PREVENTED OR MANAGED?

Every site should be characterized

In some areas, develop monitoring programs to examine changes in the future

Have plans in place for the worse case scenario

Continue research on processes and improved technologies

HYDROLOGY

GEOLOGY/MINERALOGY/CHEMISTRY/BIOLOGY

GEOTECH

SUMMARY Geologic processes affect the chemistry,

mineralogy, acid potential and stability of mine sites in New Mexico

Characterization (geology, hydrology, geotechnical) is important to prevent loss of life, prevent contamination of adjacent areas, and construct a stable facility

Every site requires specific characterization of the mine features, overburden, waste rock piles, tailings, foundation, and cover materials• Must control water• Must understand the effects of weathering on the

materials Continue research on processes and improved

technologies