PHOTO TOUR OF PRIORITY MINE SITES FOR RECLAMATION, UPPER ANIMAS RIVER WATERSHED, COLORADO. J. Thomas Nash U. S. Geological Survey

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1 PHOTO TOUR OF PRIORITY MINE SITES FOR RECLAMATION, UPPER ANIMAS RIVER WATERSHED, COLORADO J. Thomas Nash U. S. Geological Survey The photos in this report are presented as a supplement to earlier reports (Nash, 1999a, 1999b) describing and prioritizing mine sites on public lands in the Upper Animas River watershed that are being considered for reclamation. The photos are provide useful information for persons involved in the evaluation of sites for possible reclamation, and also may allow others to better understand the issues involved. People who have not had the opportunity to visit these mine sites can try to estimate for themselves the size of the features, the magnitude of concerns such as water flowing from mine portals, or ponder the interaction of mine drainage and mine waste on dumps. Some say that photographs do not lie, but photos can be misleading: although these photos were taken to provide a fair image of the scene, they necessarily emphasize certain features of scientific interest. Also, the viewer should remember that some aspects notably the flow volume of water change through the year. Geochemical information alluded to in the descriptions is discussed in the companion reports (Nash, 199a; 1999b) that are included on this CD. Photos are organized under several headings to help the user visualize the process of evaluating the impact of mines on the water quality of the Animas River; these photos and the descriptions provided here should not be considered to be an evaluation of these sites. Interim interpretations have been presented elsewhere (Nash, 1999a, 1999b) and many other studies and integrated interpretations are underway by scientists of the USGS (Nimick and von Guerard, 1998). The first section covers priority mine sites described by Nash (1999a, 1999b): several photos of each site attempt to show aspects of the complex interactions of mine excavations, mine waste, and water. The second section contain descriptions and photos of features that geochemists characterize at mine sites, especially features on mine dumps that must be sampled and interpreted. Sections three and four show examples of the amount and color of mine drainage and stream waters that we observe, sample and interpret as part of mine drainage and stream characterization. The colored mineral precipitates from surface waters are the first indication of contamination or acidic conditions. Section six shows representative tailings, their volumes and physical features that are part of tailings characterization. The final sections contains miscellaneous photos of other features that are relevant to the evaluation process. Two numbers are included in the descriptive text. Sites numbers starting with B are those used by the Bureau of Land Management, whereas those starting with N are assigned by Nash and are the same as used in geologic and geochemical reports (Nash, 1999a, 1999b). The second number is unique to the photo and is either that assigned by the digital camera (eg. DCP461), or assigned when a photograph was scanned (eg. SDS42). These photos started as jpg or tif digital files and were converted to Adobe Acrobat format (pdf); little or no editing was done to the original files.

2 Priority mine sites for reclamation Bandora Mine: The Bandora mine on the South Fork of Mineral Creek created mine dumps from several mine adits that are relatively large in size, and water drains from the collapsed lower adit. The mine is unusual for its ore in sedimentary host rocks. [N648; DCP461] Drainage from the collapsed lower portal at Bandora has a ph of about 5.6, apparently moderated by the sedimentary host rocks, but carries very high concentrations of iron, zinc and cadmium. [DCP454] Mine drainage from the Bandora mine has been channeled away from the dumps, but the channel has been breached and the iron-rich water flows overland. Deposition of the orange-red iron materials is actually beneficial to water quality because copper, zinc, and other metals are adsorbed on the iron colloids. [SDS42] Bonner Mine: Waste dumps from five mine adits have created a large mass of mineralized rock that weathers and reacts with waters at the surface, with flow of runoff into the nearby Middle Fork of Mineral Creek (foreground). The lowest adit with the largest discharge is not visible at the bottom of this photo. [SDS43] This telephoto view of the lower Bonner mine dumps shows the flow of water over the lowest dump; the Middle Fork is just off the bottom edge of the view. [SDS45] Mine drainage from the Bonner mine flows across the dump and into the Middle Fork of Mineral Creek (middle distance, about 200 feet away). The mine drainage water with ph 2.9 carries high concentrations of iron and very high zinc and cadmium. Reactions with dump rocks adds more base metals to the water. The flow was relatively high in September of 1999 after an unusually wet summer. [N516; DCP178] A second view of the lowest mine level at Bonner mine, shows lower flow in August of The partly collapsed mine portal is below the black rocks, next to the pine tree. [SDS44] Burbank mine: One of the largest flows of mine drainage water in the study area is from the Burbank mine tunnel, located at treeline high above the South Fork of Mineral Creek near Clear Lake. Red iron flocculates from the ph 5.7 water when it leaves the mine, probably the result of added atmospheric oxygen. [N603; DCP467]

3 Water from the Burbank mine flows over the dump and then infiltrates alluvium. Although the zinc concentrations are not high relative to many acidic waters, the high flow means that the total amount of zinc (called zinc loading ) added to the South Fork basin is significant. [DCP463] Brooklyn mine: View of the Brooklyn mine and its waste dumps above Brown s Gulch. Mine drainage from the Brooklyn mine adit flows over the waste rocks (reddish line, to right of center), reacts, and gains additional metals from the dump. [N588; DCP183] This puddle on the Brooklyn mine dump has a ph of 2.1 and extremely high metal concentrations. The puddle water is an approximation of the composition of runoff during a storm. The dump surface is gray from sulfide minerals (chiefly pyrite) that are concentrated at the surface as clay minerals wash away; deeper inside the dump the content of clay is higher than pyrite. [N588; DCP185] Mine drainage from the Brooklyn mine flows down the dump for several hundred feet. The drainage initially has a ph of 4 and becomes more acidic (ph 2.9) and the concentrations of metals are notably higher at the bottom of the dump. [DCP188] Disturbance at the Brooklyn mine covers tens of acres and includes these two tailings ponds. Material in the foreground is dump rocks, and the materials on the near side of the ponds is mixed alluvium and mine waste. Brown s Gulch is in the middle distance with trees. DCP189 East Mogul mine: The East Mogul mine (site B123) created a large dump of sulfide-rich rock near the headwaters of Cement Creek. An adit was driven northeast (left) into the mountain. A streak of red, in lower right corner, is a warning of acidic drainage; Cement Creek is on the right (white), and Ross Basin is in background to the east. [N175; SDS41] Water seeps through the dump of the East Mogul mine in the floodplain of Cement Creek (stream on left). The flow on the right, which creates red iron colloidal floc, is the first significant input of pollutants into Cement Creek. The ph is 2.9 and metal concentrations are very high. [N175; SP44e7] This is a close-up view of the acidic seep as it emerges from the East Mogul dump. The ph here is 2.9; iron precipitates as ph rises as mixing with other water occurs. [DCP134] Elk Tunnel:

4 The Elk Tunnel (site B009) on the west side of Cement Creek is one of several adits in the area that produce a large flow of near-neutral water (ph 6.4) that is rich in iron and zinc, thus the zinc loads are significant. The dump at this site is relatively low in sulfide minerals and poses minor problems, but the mine drainage is a significant source of metals. The gray box and post are used to measure the amount of flow from the adit. [N311; DCP417] This is another view of the Elk Tunnel mine drainage below the tunnel and dump. The dump is a minor problem compared to the mine drainage. Cement Creek is about 20 feet east of where photo was taken. [DCP411] Highland Mary mine: The geology of the Highland Mary mine brings good news: acidic drainage is not evident because unusual amounts of calcite are present. The mine, which has been reclaimed (arrow), is in altered volcanic rocks that contain calcite, calcite occurs in veinlets in the dumps, and fault blocks of carbonate rocks occur below the mined area (light colored craggy outcrops). Calcite and related carbonate minerals are very effective in neutralizing acidic mine drainage. [N260; SDS31] Light-colored mill tailings from the Highland Mary mill were placed next to Cunningham Creek. The tailings impound appears to be more stable than most tailings in the region, and the unusually high content of calcite mitigates any acid generated by ore minerals in the tailings; there is little or no transport of base metals into the creek. [DCP167] Imogene mine: The Imogene mine is the source of a large flow of water that precipitates red iron minerals and flows into Mineral Creek. The adit, shown here filled with rubble, was driven into brown iron-cemented rock called ferricrete (faintly layered, middle of photo). The ferricrete formed from natural acid rock drainage and presumably attracted prospectors to the site. The ferricrete is evidence for acid rock drainage before the mine was excavated. [N511; DCP174] Mine drainage from the Imogene mine reacts with and erodes the dump. The eroded waste rocks have been carried down into wetlands of Mineral Creek, and the mine drainage flows into the wetlands. The mine drainage has a ph of 5.4 and carries high amounts of iron and zinc. Because of the high flow, the loadings for iron and zinc are higher than from most mines in the study area. [N511; SDS37] Lark mine: The Lark and Henrietta mines in Prospect Gulch are adjacent to highly altered rocks of Red Mountain (background). The upper level of the Henrietta (H3) is in foreground, and Joe and John mine (J&J) is east of the Lark. Dumps from the mines,

5 foreground to center, are being evaluated for their contributions to Prospect Gulch creek and to distinguish (if possible) from the effects of the much larger volume of pyrite-altered rocks in the red alteration zones. [N204; SDS39] Contamination from the Lark mine may reach Prospect Gulch creek in several ways, including groundwater. Here we see in the foreground a spring that issues ph 2.3 water with extremely high metal concentrations; dumps of the Lark mine are in the middle and Red Mountain is in background. The spring (arrow) may be flowing along a fault that intersects the Lark deposit, the Lark tunnel, or groundwater percolating through the Lark dump. Although this spring has low flow, the extremely high metal concentrations make this a significant loader of metals in Prospect Gulch. [SP44e18] Missouri Gulch prospects: Several small adits and a shaft in Missouri Gulch created dumps that are rich in pyrite-galena-sphalerite. This site is about a quarter of a mile of the Cement Creek road, but there is no vehicle access to facilitate reclamation. [N307; DCP404] One adit drains ph 2.9 water for part of the year, and the drainage reacts with the sulfidic waste rocks to gain more metals. This mine drainage flows into the nearby creek, which then disappears into alluvium. The groundwater probably upwells into Cement Creek. [N307; DCP399] North of London mine prospect: Mining of a large quartz-sulfide vein north of the London mine (site B234) created trenches that collect acidic water (ph 2.9), and the mine waste was spread over more than an acre rather than in compact waste heaps. [SP44d3] Waste from site B234 prospect has been spread widely and kills alpine vegetation. The barren exposure in background is altered rocks on Houghton Mountain, south of Burrows Creek. [SDS38] Paradise mine: The Paradise mine on the upper Middle Fork of Mineral Creek is famous for the bright white precipitate and high flow of water from its collapsed portal. The mine drainage has ph 4.5 and carries high concentrations of aluminum, iron and zinc, but low copper and lead. Possibly the mine water is a mixture of several kinds of ground water, some of which may have been more acid than ph 4 and derived from oxidizing sulfide minerals in the red-altered rocks in the mountain above (Nash, 1999a). The white precipitate covers red material that has the appearance of typical iron floc on other mine dumps [N520; DCP345]

6 This close-up view of the Paradise mine dump shows the fine-grained white material resting on red material; water splashing into the air is less white than the precipitate (upper left in photo). The white material contains both aluminum and iron in this case the white color not indicative of the composition. [SDS47] Springs near the Paradise mine (this one is 300 yards southwest of the Paradise portal) also release iron-rich water. These mine and spring waters all have the tendency to precipitate iron floc at about ph 4 to 5. The spring waters are natural flows, probably along fracture zones. [SP44a16] Mine site characterization The mine dump of the Culvert mine (site B060) is on the west side of Cement Creek. These moderately sulfidic waste rocks are influenced by shallow ground waters, which are monitored by research wells (one is in lower right corner of photo). [N303; DCP148] Site B116 is about a quarter of a mile east of Cement Creek in a side canyon. The mine dump is fairly small and contains less sulfide than most dumps. Leach tests suggest that the dump rocks are not a high priority problem, but the mine drainage may need reclamation. [N309; DCP406 ] The adit at site B116 drains ph 3.8 water carrying high concentrations of iron, copper, and zinc. Reactions with the dump rocks adds more metals to the drainage. Mine drainage is the concern at this site. [N309; DCP408] The Silver Wing mine, dumps, and mill site, east of the Animas River and north of Eureka, are on private property. The mine drainage produces conspicuous red iron floc on the right side of the dump, but the waters are neither highly acidic nor rich in metals. [DCP199] The San Juan mine worked a large quartz-sulfide vein that extended for thousands of feet. This site is just north of the study area, in the Uncompahgre River watershed. Water draining the lower portal has ph 2.8, but the green propylitic alteration in this area neutralizes the acidic mine drainage within a short distance. [DCP221] The Vermilion mine and mill worked a vein deep under the mountain, producing a medium-sized dump rich in clay and pyrite, and the small mill (left of road) produced a small volume of light-colored tailings to the right. California Gulch creek is about 200 feet to the right. [DCP233] View of the mine dump and associated features of site B105; Dry Gulch is in the foreground. The dark reddish brown colors are from iron oxides created by mine drainage that flows over the dump. The partly open, small mine portal is the dark spot in the center of the picture, immediately above the brown dump rocks. The prospect adit was driven into an outcrop of ferricrete. [N201; DCP140]

7 These red, highly altered rocks on the flank of Anvil Mountain were prospected (site B248), but the mine workings and dumps are difficult to identify amongst the talus. The sulfide-rich talus and mine waste slide down the slope, becoming intermixed. The effects of mining and weathering of unmined rocks are difficult to distinguish at sites like this. This site is about a mile north of Silverton, adjacent to route 550. [N300; SDS35] Reactions with mine drainage at this small pyrite-rich dump cause additional degradation of waters. This site is northeast of Animas Forks, in sight of the road to Engineer Pass. [Site B169; N144; DCP207] This small prospect is in the alpine area of Sunnyside Basin, the original site of the large Sunnyside mine shaft. There is no drainage from mine workings, but runoff from the sulfidic dump kills nearby vegetation. [Site B144; DCP265] Another view of prospect B144, Sunnyside Basin, looking down from the dump to the kill zone in alpine flora below the dump. [B144; SDS34] Mine drainage characterization Mine drainage rich in iron precipitates iron floc as ph rises or oxygen is added. This small prospect explored a zone of ferricrete (the brown rock above the metal grill that is used to close the portal). The draining water is near-neutral (ph 6.9), but carries elevated concentrations of iron and a few other metals. The water is arguably a natural flow that was intersected by the small mine workings (Nash, 1999a). The hillside above Mineral Creek, north of the Imogene mine, contains abundant ferricrete an iron cement that clearly formed before mining. [N512; DCP172] The Silver Ledge mine, near the East Fork of Cement Creek, releases a flow of water that is so large that it has been shown as a stream on topographic maps. The flow, measured at gpm, is not highly acidic (ph 5.7) but carries substantial amounts of iron and zinc, thus it is a significant loader of iron and zinc in the Cement Creek watershed. This mining area has mixed land status: the mine is on patented land, whereas the dump and mine drainage are on public land. [SDS48] A very large flow of water from the Ruby Trust adit (collapsed) flows over the mine dump. This water with ph 6.4 is not as rich in metals as many mine drainage waters, but the high flow means that loadings of iron and zinc are substantial. Reactions with waste rocks add more metals to the surface water. [N524; DCP179] The Kitti-Mack mine (site B022) is located at treeline, high above Minnie Gulch. The dump has relatively low content of sulfide minerals, and the mine drainage (white, left of center) has ph 5.6 and low conductivity and low metal concentrations. This mine drainage makes no red iron floc and is considered to be much less

8 contaminated than most mine drainage waters. Ore was carried from the wooden structure to a mill at Middleton in a tram. [N235; DCP259] The Mammoth mine, upper Cement Creek basin, releases a large flow of mine drainage reacted with mine waste for many years, forming the conspicuous red iron oxide minerals. In these reactions, acid and metal concentrations increase in the draining water. Cement Creek is a short distance east of this dump. This site (B001) was reclaimed in the summer of 1999 (photo take August, 1998). [SDS36] An obscure collapsed mine portal discharges substantial amounts of drainage that flows into the Upper Animas River, less than 100 feet to the west. This water with a ph of 6.9 carries significant amounts of iron, which precipitates when it becomes oxygenated at the surface. This site is about 1 mile south of Howardsville. [SP44a23] This site (B233) near the headwaters of the Animas River, north of Denver Lake, is not large but the mine drainage with ph 3.5 reacts with sulfidic mine waste and kills alpine vegetation below. Wetlands to the east, near the road to Engineer Pass, are not obviously stressed by the discharge. [N160; DCP218] The Bullion King mine is a prominent site above treeline near Bullion King Lake, west of Red Mountain Pass. The dump is unusually rich in clay and sulfide minerals, and these materials react with mine drainage, producing degraded water that leaves the mine site with ph 4.6 and elevated metal content. [N594;DCP359] Stream characterization This photo illustrates the complexity of surface-water chemistry in the study area: the stream on the right (Cement Creek) mixes with the East Fork (clear because the ph of 2.2 keeps metals in solution), and within a few feet orange material (ironoxyhydroxide-sulfate, schwertmanite) precipitates from the mixed ph 3 waters. The fine-grained orange material is very soluble in lab tests and is believed to dissolve during high flow conditions (G. Desborough, oral commun., 1999). [SP44e13] Acidic, iron-rich waters can form the mineral schwertmanite, as shown in the bed of Cement Creek at low flow. Metals such as zinc and copper tend to adsorb on the fine-grained flocculate. During high flow, the schwertmanite dissolves, releasing the adsorbed toxic metals. These reactions are confirmed by leach tests in the lab. [SDS40] Mill tailings characterization The Lackawanna mill, on the northeast edge of Silverton, placed its tailings in the floodplain of the Upper Animas River. The tailings tend to be either gray or ocher, which probably reflects different ore types that were processed here: the gray color is

9 from fine-grained sulfide minerals and the ocher color is from oxidized iron minerals. The mill is on private property but the tailings are on public lands. [DCP356] Tailings are a potential or known source of contamination at many sites in the study area, and some of the more problematic examples are fluvial tailings that have been eroded from tailings impounds and redeposited as overbank sediments, as shown here. These gray tailings are located east of the road to Eureka, about a mile south of the former mill site. Similar tailings east of the road were excavated and hauled to the Mayflower mill tailings site during a major reclamation project by Sunnyside Mines in These tailings were deposited among willows and retained by the bed of the railroad tracks. These overbank sediments may be related to the catastrophic flood of 1928 that breached the Eureka tailings impound. [SP44d21] These yellow tailings are a prominent feature along the road to Eureka. The tailings were produced by the Kitti-Mack mill, which is about 200 yards to the northeast. The tailings are in the floodplain of the Animas River, but do not extend to the river bank; possibly the old railroad bed impounded the tailings on its east side. Water percolating through these porous materials likely transport base metals into shallow groundwater, which probably flows into the river as springs.[dcp249] Little Giant Basin was the site of some of the earliest mining in the Silverton area, and the tailings from the early stamp mill have been excavated in the past 20 years. Primitive operations at this stamp mill prior to poured tailings into the creek east of the lake. [N291; DCP436] The tailings from the Little Giant mill were stacked on a plastic sheet at the edge of the alpine lake in a crude attempt to recover silver and gold by heap leaching. [DCP431] Miscellaneous photos An early guardrail protected men and mules on the pack trail to the Shenandoah mine above Little Giant Basin. This rugged trail, dating to the 1880 s, demonstrates the difficult logistics faced by the first miners and the small scale of their mining. [SP44b12] Well-exposed quartz veins such as this are common in Placer Gulch. Veins in this area are rich in manganese minerals that create black coatings on rubble, and also carry significant amounts of sulfide minerals (but not enough to merit mining). Outcropping veins like this are a source of acid and metals to nearby streams, just like mine dumps. [DCP311 Weathered rocks on Red Mountain are bright red from iron oxides (hematite and jarosite) and have the texture of materials on a mine dump. Samples of the red material have been tested in the lab using the same leach tests as used on dump

10 samples, but these samples produce little acid and release very little metal because they have already been removed during weathering. Quantitative evaluation of unmined, mineralized rocks as sources of acid and metals is difficult. [SDS46] References Nash, J. T., 1999a, Geochemical investigations and interim recommendations for priority abandoned mine sites on U.S.D.A. Forest Service lands, Mineral Creek watershed, San Juan County, Colorado; paper edition: U.S. Geological Survey Open-File Report , 40 p. Nash, J.T., 199b, Geochemical investigations and interim recommendations for priority abandoned mine sites on USBLM lands, Upper Animas River watershed, San Juan County, Colorado; paper edition: U.S. Geological Survey Open-File Report , 45 p. Nimick, D. A., and von Guerard, Paul, 1998, editors, Science for Watershed Decisions on Abandoned Mine Lands: Review of Preliminary Results, Denver, Colorado, February 4-5, 1998: U.S. Geological Survey Open-File Report , 70 p.