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Abandoned Mine Lands Assessment of the North Yuba Watershed
Purpose and Scope
• California Bay-Delta Authority contracted with the Department of Conservation to select a high priority watershed and perform an assessment of the abandoned mine issues.
• Collected data during field work and combined with historical data to form the North Yuba Watershed database.
Watershed Selection
• Watershed based on water flowing in to the bay-delta area.
• Selection criteria for priority watersheds were created by analyzing many geospatial datasets.
• Watershed was partitioned into 2 regions: Coast Range and the Sierra Nevada.
• Sierra Nevada Province: anthropogenic mercury and arsenic
• Coast Range Province: natural mercury and geothermal activity.
Geospatial datasets • Seven datasets used in watershed selection:
– Principle Areas of Mine Pollution (PAMP), mines with production over $100,000 that could impact WQ
– arsenic occurrences, derived from USGS’s Mineral Resources Data System (MRDS).
– public ownership, public vs. private.– acid rock drainage, sites with acid generating ore
minerals and bodies from MRDS. – historic hard rock mining, from USGS 1:24,000 topo
maps– historic hydraulic mining, from USGS 1:24,000 topo
maps– watershed boundaries
Spatial Data Set Description Very Low Low Moderate High Very High ExtremeNumber of Principal Areas of Mine
Pollution (PAMP) Sites0 1-19 20 - 29 40- 59 60 - 69 > 79
Public Ownership in Acres by Watershed
0 1-9,99910,000 – 49,000
50,000 – 99,000
100,000 – 199,000
> 200,000
Number of Abandoned Mines that may have Acid Rock Drainage by
Watershed0 1-9 10-19 20 - 29 30 - 40 > 40
Number of Hard Rock Mines by Watershed
0 1-9 10-49 50 - 99 100 - 200 > 200
Number of Abandoned Mines that may have Arsenic by Watershed
0 1-3 4-6 7-9 10-12 > 12
Area in Acres of Hydraulic Mines Sites by Watersheds
0 1-99 100 - 249 250 – 499 500 – 999 > 1,000
Category Score 0 1 2 3 4 5
Very Low Low Moderate High Very High ExtremeRange of Summed Scores 0 1-4 5-9 10-14 15 - 20 > 20
Overall Watershed Ranking Value0 1 2 3 4 5
Matrix for Scoring Watershed Categories
Matrix for Ranking Watersheds
Watershed Name
Sum of Category Scores
Overall Watershed Ranking
ValueNorth Yuba 27 5
Copperopolis 22 5Middle Yuba 21 5South Yuba 21 5
Middle Fork American 20 4North Fork American 20 4
Upper Bear 20 4Cosumnes 19 4
South Fork American 19 4North Fork Merced 18 4
Big Oak Flat 17 4Mariposa 17 4
Buckhorn Peak 16 4Foothill Drain 15 4
Middle Fork Feather 15 4Upper Mokelumne 14 3
Bloomer Hill 12 3South Fork Calaveras 12 3
Sutter Creek 12 3Ure Mountain 12 3Clavey River 11 3
Mammoth Pool 11 3Nevada City 11 3
North Fork Feather 11 3South Fork Merced 10 3
Yosemite 10 3East Branch North Fork 10 3
Mining History
• First gold discovery party was lead by “Major” William Downie.
• Claims were set based on “30 feet per man”
• Population over 5,000 in 1851
Mining History, cont.
• Surface placers worked intensively
• Extensive hydraulic mining took place between the 1850s and 1884, with some operations worked into WWII.
• Drift placer mining developed around the same time as hydraulic mining.
• Lode gold production began in 1853 and lasted until the 1960’s
Sample Design
• Contracted to visit at least 100 sites. •128 mine sites actually
visited.
Sample Design,cont.
• Used USGS 7.5 minute topographic maps to determine where to catalog.
• 400 topo symbols in North Yuba, 221 cataloged
• Attempted to visit PAMP sites first but was unsuccessful.
Number of symbols Percent
Not Cataloged (on or near active mines) 20 5%Attempted (no features found) 21 5%Visited and cataloged 221 55%Not cataloged due to access and time constraints 138 35%
Data Acquisition
• Historical literature search (commodity, extent of workings, processing methods, etc.)
• In the field, data collected on location, character and condition of mine sites and features.
• Location information for each mine feature was collected with a Trimble GPS to an accuracy of 10 meters or less.
• Screening parameters for on-site water sources: pH, electrical conductivity, oxidation-reduction potential and temperature.
• Limited grab soil samples were taken when appropriate.
Soil Sampling• For underground mines: sampled tailings dumps and fine-
grained waste rock dumps.
• Dumps with varied physical characteristics were sampled in each discreet unit of the material.
• For hydraulic mines, sampled fine-grained tailings, sediment down gradient of probable ground sluices and tunnel exits.
• Also sampled mill areas and impoundments
Methodology:
• Top 1-2 inches was discarded and only material deeper than 1 inch was bagged in “Whirl-Pack” bags to be tested.
• The 18 oz. bags were filled 1/3 to 3/4 full, sealed and placed in a second clean and empty bag and sealed.
• GPS recorded the exact locations of each sample.
Ironsides Mine
AS=130 ppm, Hg=47 ppm, Pb=590 ppm
Soil Sample Analysis
• The soil samples were shipped to CLS Labs in Rancho Cordova.
• Samples were air dried and sieved to a particle size of 1.0 mm.
• Samples analyzed for arsenic, lead, mercury using EPA methods:
– EPA 74-71 (cold vapor test) for mercury
– EPA 60-10 (ICP) for arsenic and lead
OMR ID Mine Name Result in ppm Location462269 Lower Brush Creek 670 Mill area462241 Union-Keystone 600 Edge of impoundment462067 Monarch 310 Tailings 462116 Ironsides 130 Tailings at collapsed stamp mill462059 Columbo 53 Tailings
Arsenic
OMR ID Mine Name Result in ppm Location462234 Davis Motor 1000 Tunnel exit462116 Ironsides 590 Tailings at collapsed stamp mill462237 Pacific 140 Mill Area462241 Union-Keystone 600 Edge of impoundment322011 Secret Diggings 80 Edge of impoundment
Lead
OMR ID Mine Name Result in ppm Location462116 Ironsides 47 Tailings at collapsed stamp mill462206 Indian Hill 5 Tunnel exit462248 California 0.9 Ground sluice462250 Lucky Hill 0.68 Mine waste462241 Union-Keystone 0.63 Edge of impoundment
Mercury
Mine Name Commodity Operation type
Physical PAR Score
Chemical PAR Score
Total PAR Score
Number of Openings
Tailings (Cubic Yards)
Waste (Cubic Yards)
California Gold Hydraulic, Underground 1,504 3,062 4,566 1 0 - 5010,000 - 100,000
Columbo Gold Processing Plant/Mill 664 6,339 7,003 210,000 - 100,000 500 - 1,000
Davis Motor Gold Hydraulic, Underground 514 108 622 2 0 - 50 50 – 250
Indian Hill Gold Hydraulic, Placer, Processing Plant/Mill 5,684 7,054 12,738 310,000 - 100,000
10,000 - 100,000
Ironsides Gold Processing Plant/Mill, Underground 1,004 41 1,045 2 0 - 50 0 – 50Lower Brush
Creek Gold Underground, Processing Plant/Mill 614 2,356 2,970 1 500 - 1,000 500 - 1,000
Lucky Hill GoldPit/Quarry, Processing Plant/Mill,
Underground 334 1,149 1,483 1 50 - 2501,000 – 10,000
Monarch GoldPlacer, Processing Plant/Mill,
Underground 596 2,349 2,945 1 500 - 1,000 500 - 1,000Union
Keystone Gold Underground 694 42 736 1 0 - 50 0 - 50Secret
Diggings Gold Hydraulic 1,074 226 1,300 2 0 - 50 250 - 500
Site Summary
Priority Listing of Sites• 2 priority lists developed
OMR Id Mine Name Commodity Operation TypeChemical
PAR Score Ranking
462161 Tennessee GoldPlacer,
Underground 20,349 5462256 Unknown Gold Underground 12,427 5462227 Unknown Gold Underground 10,652 5
462213Lower Brandy City
Diggings Gold Hydraulic 10,066 5
462190Brandy City
Diggings GoldHydraulic,
Underground 10,052 5462122 Comet Gold Underground 10,051 5
Very Low Low ModerateModerately
High HighRange of Chemical PAR
Scores 0-999 1,000-1,999 2,000-2,999 3,000-3,999 >4,000Overall Site Ranking
(Inventoried Sites) 1 2 3 4 5
Matrix for Ranking Sites Based on Chemical PAR Score
Chemical PAR Score Ranking of Sites
No Very Low Low ModerateModerately
High High
Arsenic (ppm) nd 1-2.9 3-4.9 5-6.9 7-8.9 >8.9Lead (ppm) nd 1-9 10-19 20-29 30-39 >39
Mercury (ppm) nd 0.01-0.19 0.20-0.39 0.4-0.59 0.6-0.79 >0.79
Chemical Par Score n/a 1-999 1,000-1,999 2,000-2,999 3,000-3,999 >4,000
Category Score 0 1 2 3 4 5
Matrix for Scoring Sites by Chemical PAR Scores and Soil Sample Results
Very Low Low ModerateModerately
High HighRange of Summed
Scores 1-4 5-8 9-12 13-16 >16Overall Site Ranking (Sampled Sites Only) 1 2 3 4 5
Matrix for Ranking Soil Sampled Sites
OM
R I
D
Min
e N
ame
Mer
cury
(ppm
)
Mer
cury
Cat
egor
y Sc
ore
Lea
d (p
pm)
Lea
d C
ateg
ory
Scor
e
Ars
enic
(ppm
)
Ars
enic
Cat
egor
y Sc
ore
Che
mic
al P
AR
Sco
re
Che
mic
al P
AR
C
ateg
ory
Scor
e
Sum
of M
ercu
ry, L
ead,
A
rsen
ic, a
nd C
hem
ical
P
AR
Cat
egor
y Sc
ores
Ove
rall
Sam
pled
Sit
e R
anki
ng
462227 Unknown 0.6 4 25 3 12 5 10652 5 17 5462062 Keystone 0.34 2 42 5 80 5 10044 5 17 5462116 Ironsides 47 5 590 5 130 5 41 1 16 4462206 Indian Hill 5 5 20 3 4.2 2 7054 5 15 4462222 Sebastopol 0.35 2 21 3 29 5 5040 5 15 4462050 Oakland Pond 0.46 3 32 4 9.5 5 2031 3 15 4
462241Union-
Keystone 0.63 4 130 5 600 5 42 1 15 4462059 Columbo -1 0 22 3 53 5 6339 5 13 4462248 California 0.9 5 15 2 4 2 3062 4 13 4
Ranking of Soil Sampled Sites
Further Actions
• Complete inventory of the watershed, both private and public lands.
• Full site characterization, including detailed studies into the geology, hydrology and biology.
• Sampling program to examine downstream effects of high mercury, lead and arsenic concentrations.
