case studies: treatment of acid mine and metal contaminated waters using zeolites

October 07-09, 2014 | Crowne Plaza Denver Downtown | Denver, CO

Dan Eyde – St. Cloud Mining Company

Tiff Hilton – WOPEC

Barbara Carroll - GeoGRAFX

St Cloud Mining 1 10/2/2014

Zeolites are used

commercially for

several reasons:

* Unique absorption

* Ion exchange

* Molecular sieve

* Catalytic abilities

St Cloud Mining 2

Natural zeolites are hydrated aluminosilicates.

10/2/2014

Natural zeolites are readily available. The resources are

large, well tested and consistent in performance.

There are a number of available technologies that improve

sorbent selectivity or increase capacity for specific

contaminants.

Technology is proven in municipal and drinking water,

nuclear, and industrial water treatment applications and is

becoming more common in polishing mine effluents prior to

discharge.


St Cloud Mining 4

Project Contaminant

Three Mile Island Cesium, Strontium

Kendall Gold Mine – Hilger, MT Thallium, Cu, Pb, Zn, Co

Homestake Legacy Site - Grants, NM Uranium

Colorado Tailings, Butte, MT Cu, Pb, Zn, Ag - Pilot

Greenbriar Coal – West Virgina AMD, Mn, Al - Pilot

Rimcon – Wyoming Mitigation High Sodic waters

WRT – >100 Commercial installations Arsenic, Radium, Thorium, Uranium

Fukushima, Japan – Kurion Cesium, Strontium, Americium, Calcium

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Issues to be resolved included the following:

AMD – pH of the water can be extremely low

Manganese

Aluminum

Iron

Turbidity

TDS


Parameter Sample 1 Sample 2 Sample 3

pH 3.31 2.97 2.52

Dissolved Fe 2.48 9.23 617.20

Dissolved Mn 32.23 53.13 29.34

Dissolved Al 48.82 52.24 109.80

RAW WATER ANALYSIS


Parameter Raw Water After Zeolite

pH 3.31 5.71

Dissolved Fe 2.48 0.21

Dissolved Mn 32.23 8.27

Dissolved Al 48.82 0.11

Sample 1


pH 2.97 5.32




Sample 2


pH 2.52 4.00




Sample 3


Parameter Raw AMD AMD-NaOH AMD-NaOH

Zeolite

AMD-Ca(OH)2 AMD-Ca(OH)2

Zeolite

pH 3.45 10.89 8.29 11.71 9.64

Alkalinity <0.45 162.64 25.23 604.67 31.51

Acidity 739.89 <0.33 <0.33 <0.33 <0.33

Conductivity 4,410.00 4,310.00 2,548.00 4,820.00 2,677.00

Dissolved Fe 213.00 0.01 0.04 0.02 0.01

Dissolved Mn 30.50 <0.001 0.02 0.001 <0.001

Dissolved Al 52.68 1.46 <0.008 0.127 <0.008

Dissolved Na 25.78 871.30 336.20 54.44 156.80

Dissolved Mg 149.30 0.34 35.37 0.24 16.01

Dissolved Ca 194.86 84.61 221.60 936.30 518.40

TDS 3,111.00 2,914.00 2,025.00 3,320.00 2,120.00


Uranium Processing facility built 1958 on remote ranchland

Operated by Homestake or related entities through 1990

Presently inactive except for ongoing remediating

implemented in 1977

June 2007 NM lowered standard for uranium in groundwater

from 5000 ppb to 30 ppb matching the EPA MCL since 2000

Use RO to augment the groundwater cleanup activities. Brine

from RO put in evaporation ponds

Testing zeolite to treat low concentrations of Ur contaminated

water from Upper Chinle formation . Supernatent re-injected

at rate of 50-100 gpm. System design RIMCON, LLC.


Zeolite pilot-test area on the south side of the top of the large tailing

pile. Note extraction wells (white) and piping in foreground used to convey

collected groundwater to the RO treatment plant or to one of the evaporation

ponds for disposal. View looking northeast.

Zeolite Pilot-Test Area


Zeolite pilot-test pit on the top of the large tailing pile. The zeolite is

used to extract low-concentration uranium before being re-injected at 50

gallons per minute. Pit is lined with a 60 millimeter thick high density

polyethylene (HPDE) liner. View looking northeast.

Zeolite Pilot-Test Pit


Pilot scale system worked as designed.

Homestake committed to installing large scale system.

Permitting and regulatory approvals received.

Full scale installation late 2014-15.

For further information on system contact:

RIMCON, LLC

Dale Shay – Principal

[email protected]

10/2/2014St Cloud Mining 21

Kendall Mine area in intermittent operation since

1880.Present operations started in 1981 and

continued through 1995 with gold recovery

through 1997.

All components of the Closure Water Management

plan – Watershed flow augmentation,

Groundwater capture, zeolite water treatment,

discharge of treated water into the Kendall Pit in

place sine 1998


MetalConcentration (mg/L)

TCLP SPLP

Arsenic < 0.5 < 0.5

Barium < 10 < 1

Cadmium < 0.1 < 0.1

Chromium < 0.5 < 0.5

Lead < 0.5 < 0.5

Mercury < 0.02 < 0.02

Selenium < 0.1 < 0.1

Silver < 0.5 < 0.5

Thallium 1.89 0.08


Watershed area mitigation of AMD and selected

heavy metals: ◦ Raise pH of drainage waters

◦ Reduce zinc, cadmium, lead, and copper in Alum

Gulch-Flux Canyon and Cox Gulch-3R Canyon, SE

Arizona utilizing gabion retaining wall and footer

structures combined with zeolite material

adsorption


Legacy mining activity at the top of the watershed produces acid mine drainage which is incorporated in groundwater & surface water discharges (tailings, tunneling, wall rock)


Several large removal actions

and expensive mine portal

closures implemented in the

area have had little effect on

heavy metals and AMD -

impacted loading

characteristics of several

tributaries flowing into

Sonoita Creek and Patagonia

Lake.


St Cloud Mining 36

Geologic Influences on

Water and Soil and Overall

Watershed Ecology

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Average chemical composition of mine tailings in the Harshaw Creek Watershed

(measured in ppm). From Dean (1982, p.46)

TRENCH MINE TAILINGS

pH 2.6

SO4 41,076

Fe 6,050

Cu 43

Mn 4,621

Zn 838

As 466

Pb 3,972

Cd 20

Cr 16

Se 0

Hg 5.4

Ag 25

Al 528, 725

Storm-related Surface water from Trench Mine

Tailings (mg/L)


GEOLOGIC STRUCTURES

WATERSHED POSITION

Faults and

sympathetic

fractures influence

movement of water

through the system

in shallow and deep

groundwater


Load estimates calculated during base-flow conditions at

Trench Camp indicate that the discharge produces

approximately 20 lbs of combined metals (Cd+Co+Cu+Ni+Pb+Zn) per month; the World’s Fair

segment produces approximately 86 lbs of combined metals (Cd+Co+Cu+Ni+Pb+Zn) per month.


A series of gabion retainer

wall structures and stream-

bed footers with integrated

zeolite materials will be

installed in favorable areas

downstream of perennial

spring discharge points

which are the sources of

loading in the streams .


Continue monitoring water

quality inflow and outflow,

soil chemistry and aqueous

invertebrate community

health upstream and

downstream of the

implementation for overall

effectiveness and

continuity.


Daniel T. Eyde

St. Cloud Mining

520-744-8845

[email protected]


mailto:[email protected]

case studies: treatment of acid mine and metal contaminated waters using zeolites

Engineering

alkalinity st cloud

dissolved al

dissolved mn

dissolved fe

parameter raw water

parameter sample

drinking water

amd ph