ANALYTICAL RESULTS FOR 35 MINE-WASTE TAILINGS CORES

AND SIX BED-SEDIMENT SAMPLES, AND AN ESTIMATE OF THE

VOLUME OF CONTAMINATED MATERIAL AT BUCKEYE MEADOW

 ON UPPER BASIN CREEK, NORTHERN JEFFERSON COUNTY,

MONTANA

by David L. Fey1, Stanley E. Church1 and Christopher J. Finney1

Open-File Report 99-537

1999

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards

and stratigraphic nomenclature. Any use of trade, product, or firm names is for descriptive purposes only and

does not imply endorsement by the U.S. Government.

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

1 Denver, Colorado
i

Table of Contents

 Page

Abstract.......................................................................................................................... 1

Introduction.................................................................................................................... 2

Methods of Study........................................................................................................... 2

Site descriptions.............................................................................................................. 6

Discussion of results...................................................................................................... 8

Summary and conclusions................................................................................................ 15

References cited.............................................................................................................. 50

Discussion of results in tables A1 through A6................................................................... 59

Figures

Figure 1. Location of Study Area and sample locality maps.......................................... 3

Figure 2. Site configuration maps for tailings cores and bed sediments........................... 4

Figure 3 Thickness of contamination profile for main core traverse.............................. 10

Figure 4 Thickness of contamination profile for core traverse A................................... 10

Figure 5 Thickness of contamination profile for core traverse B................................... 11

Figure 6 Thickness of contamination profile for core traverse C................................... 11

Figure 7 Contour map of tailings area showing thickness of contamination..................... 14

Tables

Table 1. Coordinates of bed-sediment sites and core 98-BMF-102............................... 7

Table 2. Element concentration cutoff values for determination of contamination............ 8

Table 3. Thicknesses of contamination of tailings cores................................................ 9

Table 4. Core field numbers, depths of intervals, and interval sample descriptions........ 17

Table 5. Total-digestion concentrations for tailings core samples by ICP-AES............ 25

Table 6. Total-digestion concentrations for bed sediments by ICP-AES....................... 47

Table 7. Analytical results for 2M HCl-1% H2O2 leach extraction of bed sediments.... 48

Table 8. Total digestion concentrations for leach residues of bed sediments................. 49

Appendix

Table A1. Comparison of contract lab results with NIST values for SRM-2704.......... 52

Table A2. Comparison of contract lab results with NIST values for SRM-2709.......... 53

Table A3. Comparison of contract lab results with NIST values for SRM-2711.......... 54

Table A4. Comparison of USGS lab results with NIST values for SRM-2704............. 55

Table A5. Comparison of USGS lab results with NIST values for SRM-2709............. 56

Table A6. Comparison of USGS lab results with NIST values for SRM-2711............. 57

Table A7. ICP-AES elements and their limits of determination.................................... 58
1

ABSTRACT

Metal-mining related wastes in the Boulder River basin study area in northern Jefferson County,

Montana have been implicated in their detrimental effects on water quality with regard to acidgeneration and toxic-metal solubilization. Flotation-mill tailings in the meadow below the Buckeye mine,

hereafter referred to as the Buckeye mill-tailings site, have been identified as significant contributors to

water quality degradation of Basin Creek, Montana. Basin Creek is one of three tributaries to the Boulder River in the study area; bed sediments and waters draining from the Buckeye mine have also been

implicated. Geochemical analysis of 35 tailings cores and six bed-sediment samples was undertaken to

determine the concentrations of Ag, As, Cd, Cu, Pb,and Zn present in these materials. These elements

are environmentally significant, in that they can be toxic to fish and/or the invertebrate organisms that

constitute their food. A suite of one-inch cores of dispersed flotation-mill tailings and underlying premining material was taken from a large, flat area north of Basin Creek near the site of the Buckeye mine.

Thirty-five core samples were taken and divided into 204 subsamples. The samples were analyzed by

ICP-AES (inductively coupled plasma-atomic emission spectroscopy) using a mixed-acid digestion.

Results of the core analyses show that the elements listed above are present at moderate to very high

concentrations (arsenic to 63,000 ppm, silver to 290 ppm, cadmium to 370 ppm, copper to 4,800

ppm, lead to 93,000 ppm, and zinc to 23,000 ppm). Volume calculations indicate that an estimated

8,400 metric tons of contaminated material are present at the site. Six bed-sediment samples were also

subjected to the mixed-acid total digestion, and a warm (50oC) 2M HCl-1% H2O2 leach and analyzed

by ICP-AES. Results indicate that bed sediments of Basin Creek are only slightly impacted by past

mining above the Buckeye-Enterprise complex, moderately impacted at the upper (eastern) end of the

tailings area, and heavily impacted at the lower (western) end of the area and downstream. The metals

are mostly contained in the 2M HCl-1% H2O2 leachable phase, which are the hydrous amorphous

iron- and manganese-hydroxide coatings on detrital sediment particles.
2

INTRODUCTION

Metal-mining related wastes in the Boulder River basin study area in northern Jefferson County,

Montana have been implicated in their detrimental effects on water quality with regard to acid generation

and toxic-metal solubilization during snow melt and storm water runoff events (Buxton and others,

1997). The bed sediments and waters of Basin Creek have been impacted by contamination from mine

waste and tailings from the Buckeye-Enterprise mining and milling complex (Metesh and others, 1994).

Basin Creek is one of three major tributaries to the Boulder River in the study area, (see figure 1) and is

a contributor to water quality degradation of the Boulder River. During the late 1800’s and early

1900’s, the Buckeye and the Enterprise mines were worked together, and both used an on-site gravity

mill to concentrate ore. The mined ore contained pyrite, arsenopyrite, galena, sphalerite, and tourmaline. During World War II, a flotation mill was built in the floodplain of Basin Creek to re-process the

gravity tailings from the old mill (Metesh and others, 1994). The Buckeye-Enterprise mine/mill complex

was assessed for possible listing in the National Register of Historic Places; such listing could affect

reclamation actions. As a result of the collapsed state of most of the mining related structures, and lack

of significant architectural or engineering features, the complex was not recommended for listing. (Rossillon and Haynes, 1999). The mass of the reprocessed flotation tailings was estimated at 16,000 tons

(Metesh and others, 1994). These tailings have dispersed over a wide area (about 3.3 acres) whose

southern edge is bounded by Basin Creek. Desborough and Fey (1997) studied waste material from

nine mine sites in the Basin district and produced a qualitative scale for potential water-quality degradation resulting from these wastes. The scale was based on the combined effect of acid-generation potential, dissolved toxic metals from a passive leach, and estimated tonnage. Tailings produced by the flotation mill process in the floodplain of Basin Creek scored a nine on a scale of one (low) to nine (high).

These tailings are the subject of this investigation. This report presents analytical results for totaldigestion elemental content for 35 cores, and the total-digestion elemental content, leachable elemental

content, and the total-digestion elemental content of leach residues for six stream sediments. A similar

report covered the fluvial tailings present in High Ore Creek, downstream from the Comet mine (Fey

and Church, 1998).

METHODS OF STUDY

Sample Collection

All samples were collected from or near Basin Creek, (T8N R6W Section 36) located on the Three

Brothers, Montana USGS 1:24,000 topographic map.

Stream sediments

In October 1996, we collected 47 bed-sediment samples in the Boulder River basin, including

one from Basin Creek west and outside of the Buckeye tailings study area. In July 1997, we collected

four additional bed-sediment samples from Basin Creek on the eastern and south- ern edges of the tailings area. In July 1998, we collected one additional bed-sediment sample on Basin Creek upstream of

the tailings area and mine workings, for a total of six bed sediments from the Buckeye tailings site (figure

2). Analyses of bed-sediment samples represent the chem-
Missoula

Helena

Butte

Billings

M O N T A N A

Bozeman

Dillon

Study Area

0

0 1

1 2 MILES

2 KILOMETERS

Base from U.S. Geological Survey

Digital line graphs, 1:100,000

CONTINENTAL

DIVIDE

Basin

Weasel Gulch

Joe Bowers

Cr

Jimmys

Cr

Clear Creek

Grub

Gulch

Jack

Creek

Nellie Grant

Cr

Overland Cr

Rocker Creek

Snow drift

Creek

Hoodoo Creek

Cataract

Creek

Uncle Sam

Gulch

Deer

Creek

Basin

Creek

Saul Haggerty Gulch Boulder

River

Big

Limber

Gulch

Bishop

Creek

High

Ore

Creek

Peters Gulch

Boomerang

Gulch

Galena

Gulch

Little

Galena

Kleinsmith

Gulch

112 22'30'' o 112 15 o

46 22'30'' o

46 15' o

R.6W. R.5W.

T.8N.

T.7N.

T.6N.

P O W E L L C O

L E W I S A N D C L A R K C O

J E F F E R S O N C O 

R.4W.

BEAVERHEAD-DEERLODGE

 NATIONAL FOREST

 Jack 

Mountain

 

Gulch

Little Boulder R.

Boulder

River

N

3

98-BMS-104 (bed sediment)

Buckeye Meadow Flotation Mill Tailings

Buckeye Mine 97-BMF-101-2 through -18, -101-A1 to -A6, -B1 to -B7, and -C1 to -C5; 98-BMF-102 (cores)

96-BM-136, 97-BMS-101-19, 97-BMS-101-A7, -B7, -C7, 98-BMS-104 (bed sediments)

Figure 1. Index map of Montana showing Boulder River study area and sample locality map for

	 flotation mill-tailings cores and bed sediments from Buckeye meadow area
98-BMS-104

bed sediment

upstream

Main Traverse Line

96-BMS-136

bed sediment

101-14

Figure 2 Site map for flotation-mill tailings cores and bed sediments at or near the

 Buckeye tailings area, Buckeye meadow, upper Basin Creek, Montana

Aerial photo mosaic Image data provided by the U.S. Forest Service N

Approximate boundary of

flotation tailings

117o 17' 47'' W

Basin Creek

101-A1

97-BMS-101-19

bed sediment

"B" Traverse

97-BMS-101-A7

bed sediment

97-BMS-101-C7

bed sediment

97-BMS-101-B7

bed sediment

"C" Traverse

101-A6

"A" Traverse

101-B1

101-B7

101-10

101-7

98-BMF-102

101-13

101-C5

101-2

101-C1

4

46o 23' 39" N

0

Meters

100
5

istry of material eroded upstream of the sample site and from colloidal material coating the detrital

grains. An integrated bed-sediment sample was collected at each site by compositing 10 to 20 individual subsites within 15 m (50 ft.) of the plotted site, and collecting material from the active channel alluvium. In the field, each composited sample was sieved through a 2 mm (10 mesh) stainless steel screen,

and the minus-2mm fraction retained; the larger fractions were discarded.

Fluvial Tailings Cores

In July 1997, we collected a suite of 34 one-inch diameter cores from the north flood plain of

Basin Creek (not the active stream channel). This suite is identified as 97-BMF-101. The samples

were collected along a traverse bearing N74OE for approximately 200 meters (650 feet) starting from

the west end of the tailings area, and from three traverses (A, B, and C) perpendicular to the main line

(figure 2). All samples were collected in plastic core tubes using a stainless-steel soil probe/sampler to

depths up to 65 cm, the maximum penetration of a single probe. Typical depths were 50 to 60 cm.

Core penetration depth and actual length were recorded on-site to determine the amount of compression. An additional core was collected from the bottom of a four-foot-deep trench in July 1998. The

configuration of the site, core locations, and traverses are shown in figure 2.

Sample Preparation

Stream-sediment samples

Bed-sediment samples were dried at ambient room temperature (25OC) and sieved to minus80-mesh (<.18 mm) prior to laboratory analyses.

Flotation-tailings-core samples

Core samples were subdivided in the laboratory into subsamples (by depth) according to visual

identification of differences in mineralogy, organic content, and apparent oxidation zones. See table 4

for subsample descriptions and their depths within cores. A core compaction factor was incorporated

to determine the actual depth of the subsamples; the assigned depth for each is defined as the midpoint

of that subsample. The cores were subdivided into two to ten subsamples, typically about five. These

subsamples were then placed in a random order and ground using a vertical pulverizer with ceramic

plates to minus 100-mesh (<0.15mm). Thirty-four cores were collected from site 97-BMF-101 and

these were divided into 196 subsamples. The core from 1998, 98-BMF-102, was divided into eight

subsamples.

Sample Analysis

Total digestion ICP analysis for 32 elements

The six bed-sediment samples, leach residues for the six bed-sediment samples from the partial

extraction described below, and 204 core subsamples were digested with a mixed-acid procedure consisting of HCl, HNO3, HClO4, and HF, and analyzed for 32 elements by ICP-AES (inductively coupled

plasma-atomic emission spectroscopy) (Crock and others, 1983; Briggs, 1996). This procedure is effective in dissolving most minerals, including silicates, oxides and sulfides; resistant or refractory minerals

such as zircon, chromite, and some tin oxides are only partially dissolved. Previous investigations using
6

a variety of materials support the completeness of the digestion (Church and others, 1987; Wilson and

others, 1994). The values for total-digestion analyses for the cores are given in table 5, and the values

for total-digestion analyses for the bed sediments are given in table 6. Limits of determination for the

total digestion method are given in table A7 in the Appendix. Comparisons of values observed for three

National Institute of Standards and Technology (NIST) standard reference materials (SRM-2704,

SRM-2709 and SRM-2711) with certified values (NIST, 1993a, 1993b, and 1993c) are given in table

A1, table A2, table A3, table A4, table A5, and table A6 in the Appendix.

Warm 2M HCl-1% H2O2 leach extraction

 The use of a partial-digestion extraction enables one to determine concentrations of trace elements bound within different phases, whereas a total digestion releases all trace elements in a sample

(Chao, 1984). The six bed sediments from Basin Creek were subjected to a partial-digestion extraction consisting of warm (500

 C) 2M HCl-1% H2O2 for three hours with continuous agitation; the

leachates were subsequently analyzed by ICP-AES for 29 elements. This partial extraction releases

trace elements associated with hydrous amorphous iron- and manganese-oxide mineral coatings and

colloidal particles (Appendix III of Church and others, 1993; Church and others, 1997). Mineral coatings such as those observed in Basin Creek can contain a significant percentage of the trace elements in

a sample (Church and others, 1997). The residues from this extraction were then dried, weighed, and

subjected to the total digestion described above to determine trace element concentrations bound in the

oxide, silicate, and more-resistant sulfide phases. The data obtained from the 2M HCl-1% H2O2 extraction are presented in table 7, and the data for the total digestion of the residues are given in table 8.

Analytical limits of determination for the partial-digestion leach method are given in table A7 in the Appendix.

Site Descriptions

Stream sediments

Locations of the bed-sediment sample sites are given in table 1 and are shown on figure 2.

Bed-sediment sample 96-BM-136 is located downstream of the tailings area, just east of a 4WD road

that crosses Basin Creek. Sample sites 97-BMS-101-C7, -B7, and -A7 are located on Basin Creek,

where the three perpendicular core traverses meet with the creek. Site 97-BMS-101-19 is located on

the creek, at the far eastern end of the tailings area, and where the main core traverse meets the creek.

Site 98-BMS-104 is located upstream from the Buckeye mine, about 0.2 km (700 ft.) east of the confluence of Basin Creek with a small, unnamed northern tributary.

Flotation-tailings cores

The locations of the flotation-tailings cores and the configuration of the traverses are shown in

figure 2. Seventeen core samples (cores 97-BMF-101-2 through -101-18) were collected from the

main traverse, spaced 12 meters (40 feet) apart. No core was taken at site 1, as tailings material was

essentially absent at that point. The tailings are thickest (1.2 m or 4 ft) near the eastern part of the area,

which consists of a topographic high. The topographic high is located between sites 97-BMF-101-13

and -101-14, about 60 m (200 ft) southwest of the sediment site 97-BMS-101-19, along the main

sampling traverse. This point corresponds to the location of core 98-BMF-102
7

Traverse A is perpendicular to and crosses the main traverse between sites 15 and 16, and,

along a bearing of N16OW. There are six samples from traverse A, starting at the upper (north) end.

Two cores were collected north of the main traverse, and four cores were collected south of the main

traverse. The spacing between these cores was 6 m (20 ft), except between 97-BMF-101A2 and -

101A3, which were 12 m (40 ft) apart; no core was taken at the intersection of traverse A and the main

traverse.

Traverse B crosses the main line at site 97-BMF-101-12. Traverse B is also perpendicular to

the main traverse, and has the same bearing as Traverse A. The spacing between cores was 12 m (40

ft). Two cores (97-BMF-101B1 and -101B2) were collected north of the main line, and four cores

(97-BMF-101B4 through -101B7) south of the main line. Site 97-BMF-101B3 is the same as the

main traverse site 97-BMF-101-12, and so a second core was not taken at this site.

Traverse C is located near the western end of the main traverse, crossing at site 97-BMF-101-

5. It is also perpendicular and has the same bearing as traverses A and B. Two cores (97-BMF101C1 and -101C2) were collected north of the main line, and three (97-BMF-101C3, -101C4 and -

101C5) were collected south of the main line. The spacing between cores on traverse C was 6 m (20

ft), except between 97-BMF-101C2 and C3, which was 12 m (40 ft). As with traverse B, a second

(duplicating) core was not collected from the intersection of traverse C with the main line. The depths

of each core subinterval, along with sample descriptions for each subsample, are given in table 4.

In July 1998, we dug trenches through the tailings with a track-mounted backhoe at several locations on the tailings area. The purpose of digging these trenches was to determine the depth of tailings, especially through the thickest section where sample cores from 1997 did not penetrate through

the bottom, and to sample the lower part of the tailings. We took a core (98-BMF-102) from the bottom of one four-foot-deep trench that was located essentially at the high part of the topographic mound,

the thickest part of the tailings. The subsample descriptions and depths for this core are also presented

in table 4.

Table 1. Localities of bed-sediment sites and core 98-BMF-102, in decimal degrees.

 Bed Sediment

 Field Number N. Latitude W. Longitude

 96-BM-136 46.39471 112.29825

 97-BMF-101-C7 46.39463 112.29557

 97-BMF-101-B7 46.39472 112.29436

 97-BMF-101-A7 46.39520 112.29398

 97-BMF-101-19 46.39557 112.29374

 98-BMS-104 46.39611 112.28944

 Site 98-BMF-102, post site at

 high point of tailings mound 46.39541 112.29450

Discussion of Results

Tailings Cores
8

Examination of total digestion data (table 5) reveals that the majority of the core samples contain

contamination from the environmentally important elements Ag, As, Cd, Cu, Pb, and Zn. Along the

main traverse, the maximum concentrations (in ppm) for the elements listed above are: silver 290; arsenic 63,000 (6.3 %); cadmium 370; copper 4800; lead 93,000 (9.3 %); zinc 28,000 (2.8 %). Along

traverse A, the maximum concentrations (in ppm) for the elements listed above are: silver 100; arsenic

23,000 (2.3 %); cadmium 130; copper 470; lead 17,000 (1.7 %); zinc 420. Along Traverse B, the

maximum concentrations (in ppm) for the listed elements are: silver 180; arsenic 24,000 (2.4 %); cadmium 130; copper 390; lead 31,000 (3.1 %); zinc 460. Along Traverse C, the maximum concentrations (in ppm) for the listed elements are: silver 150; arsenic 38,000 (3.8 %); cadmium 200; copper

1,200; lead 26,000 (2.6 %); zinc 530. In addition to the high concentrations of these trace elements,

there is generally attenuation of the trace elements with depth. However, several cores, notably 97-

BMF-101-13, 97-BMF-101-14, and 97-BMF-101-B1, do not penetrate below the level of contamination. This is illustrated by the failure of silver and lead to diminish by the cores’ bottoms.

The subsample descriptions presented in table 4 generally include the depths in the cores where

the samples contain sandy material with either fresh or oxidized micas. This material is sediment deposited by a meandering stream, and includes unmineralized material derived from the Butte quartz

monzonite (oral commun., J. M. O’Neill, 1999). This stream deposit is often capped by a soil horizon,

upon which the tailings were deposited. The depth to which the actual tailings material extends can be

estimated by the behavior of silver, which is relatively immobile in these tailings cores. The depth at

which the concentration of silver was not detected generally corresponds to the depth at which micas

(and hence pre-tailings stream sand) are present. Some of the uppermost core samples also include the

presence of micas, although this is probably the result of later sandy material being transported onto and

mixed with the upper tailings. Numerous subsamples at depth contain charcoal and/or other organic

matter, also indicating that these samples are below the original level of tailings.

The depth of contamination is deeper than the depth of the original tailings, as a result of the

downward migration of trace elements from the tailings. This is illustrated most clearly by the downward decreases in concentrations of arsenic, cadmium, copper, and zinc. Lead, however, behaves in a

fashion similar to silver, in that its concentrations do show significant attenuation with depth. We determined the depths of contamination based on the values shown below in table 2. These limits are operationally defined, and are approximately 10 to 50 times the crustal abundance concentrations. Note

that the regional background values for lead and zinc are higher than crustal abundance. Crustal abundance data are from Fortescue (1992) and the regional background values are from our unpublished

work in the Boulder study area.

Table 2 Element concentration cutoff values for determination of contamination

Element Ag Cd Cu Pb Zn

Cut-off value 5 ppm 5 ppm 300 ppm 100 ppm 500 ppm

Crustal abundance 0.08 ppm 0.16 ppm 68 ppm 13 ppm 76 ppm

Ratio 62 31 4.4 8 7

Regional background <2 ppm <2 ppm 30 ppm 55 ppm 170 ppm
9

Arsenic concentration was not used in the determination of the depth of contamination. Although arsenic levels often diminish with depth in these samples, the concentrations in some cores, particularly from the eastern half of the tailings area, remain high (table 5). In those cores, far greater

depths would be required to reach regional baseline levels of arsenic. Bed sediments collected at and

downstream of the tailings complex also show high arsenic levels (up to 4,500 ppm, as shown in table

6). However, despite the high concentrations of arsenic in the core material, their proximity to Basin

Creek, and the high arsenic concentrations in the bed sediments, soluble arsenic in the stream water at

low flow is not elevated. Metesh and others (1994, Appendix V) reported 2.4 μg/L (ppb) arsenic in

stream water collected above the Buckeye-Enterprise complex, and 20 μg/L arsenic in stream water

collected below the mines and tailings. Neither value exceeds EPA primary or secondary drinking water standards, or EPA chronic or acute aquatic life standards (Metesh and others, 1994, table 18). In

contrast, concentrations in the stream-water sample collected below the mines and tailings did exceed

the EPA chronic aquatic life standards for copper, lead, and zinc (Metesh and others, 1994, table 18).

Therefore we used concentrations of copper, lead, and zinc, as well as silver and cadmium, but not arsenic, to delineate depth of contamination.

We used the element cutoffs to determine contamination depths by inspecting where each

core’s trace-metal values were all below the cutoffs; if any one of the five trace elements exceeded the

cutoff, that core interval was considered contaminated. Table 3 presents the depths of contamination

for each core as described. The profiles of the depths to the bottom of tailings, as determined by silver

concentrations and the appearance of micaceous sand in the sample descriptions (dashed line), and the

depths to bottom of contamination, as determined by the concentrations of cadmium, copper, lead, and

zinc (solid line), are shown in figure 3, figure 4, figure 5, and figure 6.

Table 3 Thicknesses of contamination of tailings cores.

Contamination Contamination

Core Number thickness, cm Core Number thickness, cm

 97BMF-101-2 57 97BMF-101-A1 23

 97BMF-101-3 41 97BMF-101-A2 53

 97BMF-101-4 23 97BMF-101-A3 51

 97BMF-101-5 21 97BMF-101-A4 83

 97BMF-101-6 60 97BMF-101-A5 52

 97BMF-101-7 59 97BMF-101-A6 39

 97BMF-101-8 45 97BMF-101-B1 30

 97BMF-101-9 27 97BMF-101-B2 43

 97BMF-101-10 42 97BMF-101-B4 55

 97BMF-101-11 61 97BMF-101-B5 45

 97BMF-101-12 63 97BMF-101-B6 15

 97BMF-101-13 120 97BMF-101-B7 22

 98BMF-102 160 97BMF-101-C1 64

 97BMF-101-14 120 97BMF-101-C2 40

 97BMF-101-15 85 97BMF-101-C3 26

 97BMF-101-16 65 97BMF-101-C4 31

 97BMF-101-17 75 97BMF-101-C5 72

 97BMF-101-18 28
Core number

T

hic

k

n

e

s

s

of m

aterial (c

m) 200

150

100

50

0

-50

estimated

depth

estimated

depth

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Figure 3. Thickness of tailings (dashed line and gray circles) and thickness of contamination

 (solid line and black squares) along main traverse line. Depths are estimated at 

 cores 97-BMF-101-13 and -14.

Core number

1 2 3 4 5 6

200

150

100

50

0

-50

T

hic

k

n

e

s

s

of m

aterial (c

m)

estimated

depth

Flotation tailings, Buckeye meadow

97-BMF-101A1 to A6, Traverse A

Flotation tailings, Buckeye meadow

97-BMF-101-2 thru -18, main traverse

Figure 4. Thickness of tailings (dashed line and gray circles) and thickness of contamination

 (solid line and black squares) along traverse A. Depths are estimated at cores

 97-BMF-101-A2, -A3, and -A4.

10
200

150

100

50

0

-50

Core Number

1 2 3 4 5 6 7

Flotation tailings, Buckeye meadow

 97-BMF-101B1 to B7, Traverse B

T

hic

k

n

e

s

s

of m

aterial (c

m)

estimated

depth

200

150

100

50

0

-50

T

hic

k

n

e

s

s

of m

aterial (c

m)

1 2 3 4 5

Core Number

Flotation tailings, Buckeye meadow

 97-BMF-101C1 to C5, Traverse C

estimated

depth

Figure 5. Thickness of tailings (dashed line and gray circles) and thickness of contamination

 (solid line and black squares) along traverse B. Depth is estimated at core

 97-BMF-101-B1.

Figure 6. Thickness of tailings (dashed line and gray circles) and thickness of contamination

 (solid line and black squares) along traverse C. Depth is estimated at core

 97-BMF-101-C5.

11
12

Main tailings traverse, cores 97-BMF-101-2 through 101-18

The profiles of the depth to bottom of tailings and the depth to the bottom of contamination for

the main traverse line are shown in figure 3. The old soil horizon, or alternatively the original horizon

marking the top of the micaceous sand, is probably relatively flat and planar, with the variation in depth

profile related to the thickness of the tailings deposited on top of this sand. When the depths are plotted

relative to a flat, planar datum, as shown in figure 3, the profile essentially reflects the topographic expression of the tailings at the surface. The datum chosen here is the average level at which the cores

reached the micaceous sand layer between cores 2 and 5, about 24 cm (0.8 ft.). This is shown as the

heavy horizontal line in figure 3. The tailings are generally quite shallow at the west end of the traverse,

having a depth of less than 30 cm (1 ft.) between cores 2 and 5. The depth of contamination for the

first four cores is between 20 and 60 cm (0.7 to 2 ft). The depth to the bottom of the tailings and the

bottom of contamination increases at cores 6, 7 and 8, most likely due to topographic thickening. The

thickness decreases at core 9, and then increases again between cores 10 and 12. The greatest thickness occurs between cores 13 and 14. These cores, taken from the surface in 1997, did not penetrate

to the bottom of tailings or contamination. The subsequent core taken in 1998 (98-BMF-102) from the

bottom of the four-foot-deep trench, located approximately at the high point of the topographic mound,

and between cores 13 and 14, did penetrate through the tailings and trace-element migration-related

contamination. This defines the deepest and thickest zone of tailings, and the deepest level of contamination of about 160 cm (5.2 ft.).

Cores 15 through 17 did penetrate to below the level of silver, but did not reach the base of

contamination as a result of downward trace-element migration. The depths of contamination for these

cores are estimated based on their proximity to core 98-BMF-102, and the general trend seen in other

cores for the distance to which contamination persists below the silver occurrences, about 30 cm (1 ft.).

Core 97-BMF-101-18 was the easternmost core taken, about six meters (20 ft) from the bank of Basin Creek. The thickness of the tailings and contaminated material here was only about 18 cm (0.6 ft.).

Perpendicular traverses, 97-BMF-101A, 101B, and 101C

Traverse A is located near the east end of the main traverse, and intersects the main traverse at

core 16 (see figure 2). Figure 4 shows the thickness profile for this traverse. The thicknesses of contamination for cores 97-BMF-101-A2, -A3, and -A4 are estimated, since the cores’ maximum penetrations did not reach below the contamination zone. The contamination thicknesses for these cores are

also estimated to extend about 30 cm (1 ft.) below the deepest silver occurrences. Figure 4 shows that

the tailings and contamination thicknesses are least at the north end of the traverse, near the break in

slope to the quartz monzonite hill, greater in the center, and are less again at the south end of the traverse. The thickness at station -A6 is, however, 39 cm (1.3 ft.).

Traverse B is also perpendicular to the main traverse, and intersects the main traverse at core

97-BMF-101-12. The contamination depth profile is shown in figure 5. The first core, 97-BMF-101-

B1, was only 19 cm in depth and was clearly tailings material to the bottom, as reflected by a silver

content of 180 ppm in the lowest subsample. This core probably reached bedrock at shallow depth,

near the break in slope to the north. We have assigned an estimated maximum potential depth of contamination of 30 cm (1 ft.) for this core. The contamination reaches a moderate thickness of 55 cm (1.8

ft.) at core 97-BMF-101-B4, and then thins again to the south.
13

Traverse C is towards the western end of the main traverse, and intersects the main traverse at

core 97-BMF-101-5. The contamination depth profile is shown in figure 6. Core 97-BMF-101-C5,

at the southern end of traverse C, did not penetrate through the bottom of contamination, and the depth

shown is estimated, as before, from the general trend seen in other cores.

Estimate of volume of tailings

The areal extent of the flotation mill tailings at the Buckeye mine is estimated at about 13,000 m2

(140,000 ft2 or about 3.3 acres). Using the values for thickness of contamination for all the cores, a

simple contour map of the area can be constructed (figure 7) and the contour interval thicknesses integrated with their areal extent to obtain the total volume affected by contamination. The contamination

thicknesses from Table 3 were arranged in increasing order, and assigned to one of five classes, A-E.

The classes were assigned thicknesses that represented an approximation of the average for those cores

contained in it. Nine cores had thicknesses in the “A” class (25 cm), fifteen in the “B” class (50 cm),

four in the “C” class (65 cm), four in the “D” class (80 cm), and three in the “E” class (140 cm). The

symbols were then plotted on the site map, and contours developed to estimate areas of similar thickness. For the area beyond the “A” contour, but within the approximate boundary of tailings, a value of

10 cm was used to represent the thickness (area shown marked by “X’s”). This designation was for

use in estimating volumes, only; the sites marked with “X’s” do not represent actual core sites or thickness measurements. In addition, the contours developed are also approximations for use in volume estimates, and are not meant to indicate actual thicknesses. Their positions and values along the four traverses are good estimates, but since the sampling plan is not a true grid, the contour positions far from

actual core sites (as in the large area between traverses B and C and south of the main traverse) are

necessarily rough approximations. The areal extent of each class is as follows: class X, 5,250 m2; class

A, 4,200 m2; class B, 2,600 m2; class C, 700 m2; class D, 410 m2; and class E, 120 m2. The sum of

the products of the class areas and depths yields a total volume estimate of 3,800 cubic meters, or

5,000 cubic yards. Using an average value for density of the core material of 2.2 g/cm3, a calculation for

mass yields an estimate of 8,400 metric tons.

Bed sediments

The analytical data derived from the stream sediments clearly show contribution of traceelements from the tailings (table 6). The uppermost sample taken, above the Buckeye-Enterprise mine

complex and tailings (98-BMS-104), has total-digestion concentrations of the six elements As, Ag, Cd,

Cu, Pb, and Zn, at or near the regional uncontaminated geochemical baseline values, with little influence

from prospects farther upstream. Sample 97-BMS-101-19, from Basin Creek at the far eastern edge

of the tailings, shows slight elevations in concentrations. Sample 97-BMS-101-A7 shows the beginning

of influence from the tailings, mostly as increased arsenic and lead concentrations. Samples 97-BMS101-B7, -C7, and 96-BM-136 all show marked increases in concentrations. Basin Creek probably

receives tailings between 97-BMS-101-19 and 97-BMS-101-A7 mostly as material that sloughs off

the banks. West of the thick topographic mound centered on 98-BMF-102, the tailings gently slope to

the south, and are dissected by surface drainage channels. Sheet flow and surface runoff during storm

events or spring snowmelt
0 100 Meters

Explanation:

Thickness of

contamination

A = 25 cm (10 in)

C = 65 cm (26 in)

D = 80 cm (31 in)

E = 140 cm (55 in)

X = 10 cm (4 in)

B = 50 cm (20 in)

X

X

X

X

X

X

X

"C" Traverse

"A" Traverse

A

B

B

B

A

B

B Main Traverse Line

A

B

C

D

A

A

B

B

A

A

B

B

B

C

C

E

A

B

B

B

B

E

E

D

D

D

C

"B" Traverse

Aerial photo mosaic Image data provided by the U.S. Forest Service

N

X

A

Basin Creek

14

A

B

A

A

A

B

B

C

D

Figure 7. Contour map of flotation-mill tailings area, showing estimated thicknesses of contamination. Thickness contours

 are for areal and volume estimates, and do not necessarily represent thickness at a given location. See text for

 discussion.	 
15

probably carry more material to the creek west of traverse B. The concentrations of arsenic and lead

are significantly higher from 97-BMS-101-B7 downstream to 96-BM-136.

Analyses of trace elements from the warm 2M HCl -1% H2O2 leach (table 7) show that much

of the trace-element content in the bed sediments is in the leachable phase. This partial extraction releases metals associated with hydrous amorphous iron- and manganese-oxide coatings and colloidal

particles incorporated into the bed sediments (Church and others, 1997). The extraction solution only

weakly attacks primary sulfide grains with the exception of galena (PbS), which is readily soluble in

warm 2M HCl. The ratio of leachable to total concentrations for the metals reveals information about

the mineral phases harboring and transporting the different metals in the bed sediments.

Examination of the individual elements from the six bed sediments reveals the following

1. Silver in the leachable phase comprises 40% to 90 % of the total.

2. Arsenic in the leachable phase comprises 45% to 88% of the total arsenic.

3. Cadmium in the leachable phase comprises up to 100% of the total cadmium.

4. Copper in the leachable phase comprises 50% to 90% of the total.

5. Lead in the leachable phase comprises 70% to 100% of the total lead (although since 

 the leach solubilizes primary galena, one cannot differentiate between primary-mineral

 lead and adsorbed lead.

6. Zinc in the leachable phase comprises 60% to 83% of the total zinc.

The leachability of trace elements, as released by the 2M HCl -1% H2O2 leach, from the bed

sediments does not directly correspond to the downward mobility of these same elements in the flotation

tailings cores. The 2M HCl -1% H2O2 solution is more effective in its ability to leach trace elements

than the pore waters encountered in the tailings. Evidence of this is reflected by the relative downward

immobility of silver and lead in the tailings but high leachability of these two elements when subjected to

the 2M HCl -1% H2O2 leach. The leachability data of the bed sediments reflect the process of element

sorption onto colloids and iron- and manganese-hydroxides, and subsequent settling and incorporation

into bed sediments. This process helps describe elemental transport in bed sediments downstream, as

discussed in Church and others (1997). The pH of tailings pore waters was as low as 3.5; dissolved

oxygen was as low as 4 ppm. Otherwise, the nature of the pore water and its ability to leach, compared to the 2M HCl-1% H2O2 leach, was not determined. A pore-water sample from the four-footdeep trench (core site 98-BMF-102) at a depth of about three and a half feet, in gray, unoxidized tailings contained high concentrations of iron (1,700 mg/L), copper (130 mg/L), zinc (420 mg/L), and arsenic (620 mg/L). The lead concentration was 3,600 μg/L, cadmium was 2,000 μg/L, and silver was

low at only 7.5 μg/L. Thus, trace-element downward migration in the tailings pore waters is significant,

but the magnitude and processes involved cannot be estimated by or compared with the 2M HCl-1%

H2O2 leach.

Summary and conclusions

Analytical results for 35 cores collected from flotation tailings from the Buckeye mill tailings site

reveal that six environmentally important trace elements (Ag, As, Cd, Cu, Pb and Zn) are present at

high concentrations. Contamination from five of the six trace elements (not including silver) persists to a
16

depth of about 30 cm (1 ft.) below the tailings, as a result of downward migration into the underlying

pre-mining material, mostly quartz monzonite-derived micaceous sand. Calculations based on the contamination depths and areal extent indicate that the total volume of contaminated material (tailings and

underlying contaminated sandy material) is about 3,800 m3 (5,000 cubic yards), or about 8,400 metric

tons. Analyses of six bed sediments from Basin Creek show significant influence from the mill tailings.

The greatest impact on the bed-sediment chemistry occurs downstream of the eastern half of the tailings,

where runoff from storms and spring snowmelt enters the creek from surface drainage channels. Partial

extractions of the bed sediments reveal that a significant fraction (40% to 100%) of the named trace

elements are present in phases solubilized by a warm 2M HCl -1% H2O2 leach. These leachable

phases include settled colloids and hydrous amorphous iron- and manganese-hydroxide coatings of

bed-sediment particles.
50

REFERENCES CITED

Briggs, P.H., 1996, Forty elements by inductively coupled-plasma atomic emission spectrometry,

in Arbogast, B.F., ed., Analytical methods manual for the Mineral Resources Program,

U.S. Geological Survey Open-File Report 96-525, p. 77-94.

Buxton, H.T., Nimick, D.A., von Guerard, P., Church, S.E., Frazier, A., Gray, J.R., Lipin, B.R.,

Marsh, S.P. Woodward, D., Kimball, B., Finger, S., Ischinger, L., Fordham, J.C., Power,

M.S., Bunck, C., and Jones, J.W., 1997, A science-based Watershed strategy to support

effective remediation of abandoned mine lands: in Fourth International Conference on

Acid Rock Drainage Proceedings, v. IV, Vancouver, B.C. Canada, May 31-June 5, 1997,

p. 1869-1880.

Chao, T.T., 1984, Use of partial dissolution techniques in geochemical exploration: Journal of

Geochemical Exploration, v. 20, p. 101-135.

Church, S.E., Mosier, E.L., and Motooka, J.M., 1987, Mineralogical basis for the interpretation

of multielement (ICP-AES), oxalic acid, and aqua-regia partial digestions of stream

sediments for reconnaissance exploration geochemistry: Journal of Geochemical 

Exploration, v. 29, p. 207-233.

Church, S.E., Holmes, C.E., Briggs, P.H., Vaughn, R.B., Cathcart, James and Marot, Margaret,

1993, Geochemical and lead-isotope data from stream and lake sediments, and cores from

the upper Arkansas River drainage: Effects of mining at Leadville Colorado on heavymetal concentrations in the Arkansas River: U.S. Geological Survey Open-File Report

93-534, 61 p.

Church, S.E., Kimball, B.A., Fey, D.L., Ferderer, D.A., Yager, T.J., and Vaughn, R.B., 1997,

Source, transport, and partitioning of metals between water, colloids, and bed sediments

of the Animas River, Colorado: U.S. Geological Survey Open-File Report 97-151, 135 p.

Crock, J.G., Lichte, F.E., and Briggs, 1983, Determination of elements in National Bureau of

Standards geologic reference materials SRM 278 obsidian and SRM 688 basalt by

inductively coupled plasma-atomic emission spectroscopy: Geostandards Newsletter, v.

7, p. 335-340.

Desborough , G.A., and Fey, D.L., 1997, Preliminary characterization of acid-generating potential and toxic metal solubility of some abandoned metal-mining related wastes in the Boulder

 River headwaters, northern Jefferson County, Montana: U.S. Geological Survey Open File Re-

 port 97-478, 21 p.

Fey, D.L., and Church, S.E., 1998. Analytical results for 42 fluvial tailings cores and 7 stream 

sediment samples from High Ore Creek, northern Jefferson County, Montana, U.S. Geological Survey Open File Report 98-215, 49 p.

Fortescue, J.A.C., 1992, Landscape geochemistry: retrospect and prospect--1990: Applied Geochemistry, v. 7, p. 1-54.

Metesh, J., Lonn, J., Duaime, T., and Wintergerst, R., 1994, Abandoned-inactive mines program 

Deer Lodge National Forest, Volume I-Basin Creek Drainage: Montana Bureau of Mines 

and Geology Open-File Report 321, 131 p.

National Institute of Standards and Technology (NIST), 1993a, Certificate of Analysis Standard

Reference Material 2704, Buffalo River Sediment.
51

______, 1993b, Certificate of Analysis Standard Reference Material 2709, San Joaquin Soil.

______, 1993c, Certificate of Analysis Standard Reference Material 2711, Montana Soil.

Rossillon, M., and Haynes, T., 1999, Basin Creek Mine Reclamation Heritage Resource Inventory 1998 Volume I. Renewable Technologies, Inc., Butte, Montana, 126 p. Submitted to 

Beaverhead- Deerlodge National Forest, Dillon, Montana

Wilson, S. A., Briggs, P.H., Mee, J.S., and Siems, D.F., 1994, Determinations of thirty-two

major and trace elements in three NIST soil SRMs using ICP-AES and WDXRF: 

Geostandards Newsletter, v. 18, p. 85-89.
52

Appendix

TABLE A1 Comparison of contract laboratory results with NIST values for SRM-2704

SRM-2704 n=20

observed observed NIST NIST PERCENT

Element conc. % RSD value C.I.* RECOVERY

 Al % 5.71 2.8 6.11 0.16 93

 Ca % 2.61 5.6 2.6 0.03 100

 Fe % 3.73 3.9 4.11 0.10 91

 K % 1.84 4.9 2.00 0.04 92

 Mg % 1.12 3.3 1.2 0.02 93

 Na % 0.56 4.8 0.55 0.014 102

 P % 0.08 8.1 0.099 0.003 81

 Ti % 0.33 5.3 0.457 0.018 72

 Mn, ppm 550 4.3 555 19 99

 Ag, ppm <2

 As, ppm 33.6 60 23.4 0.8 144

 Ba, ppm 405 14 414 12 98

 Cd, ppm <2 3.45 0.22

 Ce, ppm 62 3.7 72 86

 Co, ppm 10.9 0.7 14 0.6 78

 Cr, ppm 76.6 20 135 5 57

 Cu, ppm 88.9 5.5 98.6 5 90

Ga, ppm 10.9 3.5 15 73

 La, ppm 29.2 0.8 29 101

Li, ppm 39.5 1.3 50 79

Mo, ppm 3.6 0.5

Nb, ppm 6.2 3.8

Nd, ppm 28.9 1.3

Ni, ppm 38.4 1.8 44 3 87

 Pb, ppm 161 20 161 17 100

Sc, ppm 10.6 0.5 12 88

Sr, ppm 125 4.5 130 96

 Th, ppm 7.4 2 9.2 80

 V, ppm 88.4 9.8 95 4 93

 Y, ppm 18.9 0.9

Yb, ppm 2.1 0.3 2.8 75

 Zn, ppm 375 22 438 12 86

* 95% confidence interval

This table shows the results for twenty analyses for SRM-2704 submitted as blind samples to the contract

laboratory.
53

TABLE A2 Comparison of contract laboratory results with NIST values for SRM-2709

SRM-2709 n=20

observed observed NIST NIST PERCENT

 Element conc. % RSD value C.I.* RECOVERY

 Al % 7.02 3.4 7.5 0.06 94

 Ca % 1.82 3.4 1.89 0.05 96

 Fe % 3.26 3.4 3.50 0.11 93

 K % 1.89 5.3 2.03 0.06 93

 Mg % 1.41 5.1 1.51 0.05 93

 Na % 1.11 6.5 1.16 0.03 96

 P % 0.05 11 0.062 0.005 81

 Ti % 0.35 2.8 0.342 0.024 102

 Mn, ppm 482 4.80 538 17 90

 Ag, ppm <2 0.41 0.03

 As, ppm 27.7 14 17.7 0.8 156

 Ba, ppm 903 24 968 40 93

 Cd, ppm <2 0.38 0.01

 Ce, ppm 42.6 2.1 42 101

 Co, ppm 10.6 0.7 13.4 0.7 79

 Cr, ppm 41.2 16 130 4 32

 Cu, ppm 30.1 1.3 34.6 0.7 87

Ga, ppm 14.2 14 101

 La, ppm 21.7 1.2 23 94

Li, ppm 47.5 1.3 50 95

Mo, ppm <2 2

Nb, ppm 8.1 4.6

Nd, ppm 18.5 0.7 19 97

Ni, ppm 72.5 2.5 88 5 82

 Pb, ppm 30 12 18.9 0.5 159

Sc, ppm 11 0.3 12 92

Sr, ppm 215 7.8 231 2 93

 Th, ppm 9.8 0.8 11 89

 V, ppm 108 8.3 112 5 96

 Y, ppm 13.4 0.5 18 74

Yb, ppm 1.8 0.2 1.6 113

 Zn, ppm 95.6 8.6 106 3 90

* 95% confidence interval

This table shows the results for twenty analyses for SRM-2709 submitted as blind samples to the contract

laboratory.
54

TABLE A3 Comparison of contract laboratory results with NIST values for SRM-2711

SRM-2711 n=20

observed observed NIST NIST PERCENT

 Element conc. % RSD value C.I.* RECOVERY

 Al % 6.33 2.79 6.53 0.09 97

 Ca % 2.81 3.73 2.88 0.08 98

 Fe % 2.70 1.75 2.89 0.06 93

 K % 2.34 4.76 2.45 0.08 95

 Mg % 0.99 3.62 1.05 0.03 94

 Na % 1.16 4.30 1.14 0.03 101

 P % 0.07 9.59 0.086 0.007 83

 Ti % 0.29 1.69 0.306 0.023 96

 Mn, ppm 575 4.1 638 28 90

 Ag, ppm 4.5 15 4.63 0.39 97

 As, ppm 93.8 13 105 8 89

 Ba, ppm 747 21 726 38 103

 Cd, ppm 34.6 4.9 41.7 0.25 83

 Ce, ppm 70 6.6 69 101

 Co, ppm 8 8.3 10 80

 Cr, ppm 18.1 34 47 39

 Cu, ppm 106 5.6 114 2 93

Ga, ppm 13.7 18 15 91

 La, ppm 37.2 4.7 40 93

Li, ppm 24.1 4.1

Mo, ppm <2

Nb, ppm 15 21

Nd, ppm 31.1 2.9 31 100

Ni, ppm 17.8 4 20.6 1.1 86

 Pb, ppm 1060 3.8 1162 31 91

Sc, ppm 8.8 4.2 9 98

Sr, ppm 236 2.3 245 0.7 96

 Th, ppm 12.1 12 14 86

 V, ppm 79.4 7.9 81.6 2.9 97

 Y, ppm 23 4.3 25 92

Yb, ppm 2.9 11 2.7 107

 Zn, ppm 304 3.9 350 4.8 87

* 95% confidence interval

This table shows the results for twenty analyses for SRM-2711 submitted as blind samples to the contract laboratory.
55

TABLE A4 Comparison of USGS laboratory results with NIST values for SRM-2704

 SRM-2704 n=7

USGS USGS NIST NIST PERCENT

 Element conc. % RSD value C.I.* RECOVERY

 Al % 6.04 2.5 6.11 0.16 99

 Ca % 2.64 2.8 2.6 0.03 102

 Fe % 4.07 2.5 4.11 0.10 99

 K % 1.93 3.6 2.00 0.04 96

 Mg % 1.20 0.0 1.2 0.02 100

 Na % 0.61 4.1 0.55 0.014 110

 P % 0.10 4.4 0.099 0.003 104

 Ti % 0.29 11.5 0.457 0.018 64

 Mn, ppm 580 5.6 555 19 105

 Ag, ppm <2

 As, ppm 23 19 23.4 0.8 98

 Ba, ppm 406 3.9 414 12 98

 Cd, ppm <2 3.45 0.22

 Ce, ppm 60 9.5 72 83

 Co, ppm 15.7 2.9 14 0.6 112

 Cr, ppm 146 3.4 135 5 108

 Cu, ppm 96 7.5 98.6 5 97

Ga, ppm 15 6.2 15 100

 La, ppm 30.9 0.8 29 107

Li, ppm 46.7 1.3 50 93

Mo, ppm <2

Nb, ppm 14.3 14

Nd, ppm 28.4 9.4

Ni, ppm 42.3 2.7 44 3 96

 Pb, ppm 149 6.7 161 17 93

Sc, ppm 11.7 3.4 12 98

Sr, ppm 133 4.5 130 102

 Th, ppm 9.6 17 9.2 104

 V, ppm 89 3.3 95 4 94

 Y, ppm 23.3 5

Yb, ppm 2 0 2.8 71

 Zn, ppm 431 3.6 438 12 98

* 95% confidence interval

This table shows the results for seven analyses for SRM-2704 analyzed in-house in the USGS analytical

laboratories in Denver, Co.
56

TABLE A5 Comparison of USGS laboratory results with NIST values for SRM-2709

 SRM-2709 n=7

USGS USGS NIST NIST PERCENT

 Element conc. % RSD value C.I.* RECOVERY

 Al % 7.26 1.6 7.5 0.06 97

 Ca % 1.93 2.3 1.89 0.05 102

 Fe % 3.47 1.3 3.50 0.11 99

 K % 1.89 3.4 2.03 0.06 93

 Mg % 1.49 2.4 1.51 0.05 98

 Na % 1.20 4.5 1.16 0.03 103

 P % 0.07 6.7 0.062 0.005 108

 Ti % 0.32 1.4 0.342 0.024 93

 Mn, ppm 537 1.9 538 17 100

 Ag, ppm <2 0.41 0.03

 As, ppm 18.7 20 17.7 0.8 106

 Ba, ppm 895 2.6 968 40 92

 Cd, ppm <2 0.38 0.01

 Ce, ppm 41.3 4.0 42 98

 Co, ppm 15.0 5.0 13.4 0.7 112

 Cr, ppm 124.3 5.9 130 4 96

 Cu, ppm 31.3 5.3 34.6 0.7 90

Ga, ppm 15.3 4.6 14 109

 La, ppm 23.6 3.1 23 102

Li, ppm 53.6 2.6 50 107

Mo, ppm <2 2

Nb, ppm 14.3 18

Nd, ppm 17.9 6.3 19 94

Ni, ppm 83.1 2.0 88 5 94

 Pb, ppm 14.4 20 18.9 0.5 76

Sc, ppm 11.9 3.0 12 99

Sr, ppm 227 3.1 231 2 98

 Th, ppm 10.7 8.2 11 97

 V, ppm 110.0 0.0 112 5 98

 Y, ppm 17.9 5.5 18 99

Yb, ppm 1.9 19 1.6 116

 Zn, ppm 98.9 1.3 106 3 93

* 95% confidence interval

This table shows the results for seven analyses for SRM-2709 analyzed in-house in the USGS analytical

laboratories in Denver, Co.
57

TABLE A6 Comparison of USGS laboratory results with NIST values for SRM-2711

 SRM-2711 n=7

USGS USGS NIST NIST PERCENT

 Element conc. % RSD value C.I.* RECOVERY

 Al % 6.39 3.3 6.53 0.09 98

 Ca % 2.93 3.5 2.88 0.08 102

 Fe % 2.86 3.2 2.89 0.06 99

 K % 2.34 6.0 2.45 0.08 96

 Mg % 1.04 4.7 1.05 0.03 99

 Na % 1.21 5.3 1.14 0.03 107

 P % 0.08 5.9 0.086 0.007 98

 Ti % 0.26 3.5 0.306 0.023 84

 Mn, ppm 677 14 638 28 106

 Ag, ppm 3.6 14 4.63 0.39 77

 As, ppm 100 6.6 105 8 95

 Ba, ppm 688 4.7 726 38 95

 Cd, ppm 37.3 1.9 41.7 0.25 89

 Ce, ppm 67.4 4.1 69 98

 Co, ppm 11.6 4.3 10 116

 Cr, ppm 47.0 3.4 47 100

 Cu, ppm 108 6.5 114 2 95

Ga, ppm 16.0 6.7 15 107

 La, ppm 37.9 3.8 40 95

Li, ppm 26.7 4.8

Mo, ppm <2

Nb, ppm 17.0 31

Nd, ppm 28.9 4.3 31 93

Ni, ppm 19.6 2.5 20.6 1.1 95

 Pb, ppm 1070 6.7 1162 31 92

Sc, ppm 9.3 4.9 9 103

Sr, ppm 244 3.7 245 0.7 100

 Th, ppm 13.9 4.6 14 99

 V, ppm 77.6 2.7 81.6 2.9 95

 Y, ppm 26.9 5.0 25 107

Yb, ppm 2.7 17 2.7 101

 Zn, ppm 353 5.4 350 4.8 101

* 95% confidence interval

This table shows the results for seven analyses for SRM-2711 analyzed in-house in the USGS analytical

laboratories in Denver, Co.
58

TABLE A7 ICP-AES elements and their limits of determination

Total Digestion HCl-H2O2 Leach

 Element Symbol Procedure Procedure

 Aluminum Al .005 % 30 ppm

 Calcium Ca .005 % 30 ppm

 Iron Fe .005 % 30 ppm

 Potassium K .01 % 30 ppm

 Magnesium Mg .005 % 30 ppm

 Sodium Na .005 % 30 ppm

 Phosphorous P .005 % 30 ppm

 Silicon Si -- 30 ppm

 Titanium Ti .005 % 30 ppm

 Manganese Mn 4 ppm 1.2 ppm

 Silver Ag 2 ppm 1.2 ppm

 Arsenic As 10 ppm 6 ppm

 Barium Ba 1 ppm .6 ppm

 Cadmium Cd 2 ppm 1.2 ppm

 Cerium Ce 4 ppm 2.4 ppm

 Cobalt Co 1 ppm .6 ppm

 Chromium Cr 1 ppm .6 ppm

 Copper Cu 1 ppm .6 ppm

 Gallium Ga 4 ppm --

 Lanthanum La 2 ppm 1.2 ppm

 Lithium Li 2 ppm 2 ppm

 Molybdenum Mo 2 ppm 1.2 ppm

 Niobium Nb 4 ppm --

 Neodymium Nd 4 ppm --

 Nickel Ni 2 ppm 1.2 ppm

 Lead Pb 4 ppm 2.4 ppm

 Antimony Sb -- 3.0 ppm

 Scandium Sc 2 ppm --

 Strontium Sr 2 ppm 1.2 ppm

 Thorium Th 4 ppm 2 ppm

 Vanadium V 2 ppm 1.2 ppm

 Yttrium Y 2 ppm 1.2 ppm

 Ytterbium Yb 1 ppm --

 Zinc Zn 2 ppm .6 ppm
59

Discussion of results in tables A1 through A6

The ICP-AES analyses of the core samples were done by an outside laboratory; the analyses of the

bed-sediment samples were done in-house in the USGS laboratories in Denver, Colorado. The results

from the contract laboratory are generally acceptable, but there are several notable exceptions. The recoveries were somewhat less accurate, and the variances were higher for samples run by the contract

laboratory than for those run by the USGS laboratory. Arsenic is biased high below 100 ppm, and

somewhat low above 100 ppm, relative to recommended NIST values. No recommendations are presented to normalize these analyses; at the high As levels contained in the cores, the values are acceptable. Cobalt is biased low, but is not an important element in this study. Chromium recoveries are very

low, due to incomplete digestion, and we do not recommend using the chromium analyses. Lead shows

a high bias at levels below 50 ppm, is relatively neutral at several hundred ppm, and shows a low bias at

levels greater than 1,000 ppm. The analyses are still quite acceptable for the purpose of this report.

The values for titanium from both laboratories tend to be low, due to the refractory nature of titanium

oxides, which may not be completely dissolved in this acid digestion.