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Research about Montana
Source-linked reports with geographic coverage including Montana.
Chemical analyses of coal and coal-associated rock samples from the Rosebud and McKay coal beds, Tongue River Member of the Fort Union Formation, Colstrip coal deposit, Rosebud County, Montana
As part of a continuing program by the U.S. Geological Survey to collect and chemically analyze representative samples of U.S. coals, 61 coal and coal-associated rock samples were collected from the Rosebud and McKay beds in the Paleocene Tongue River Member of the Fort Union Formation in Rosebud County, Montana. This area is located in the Montana part of the Powder River region, specifically within the Coistrip coal deposit as defined by Matson and Blumer, 1974. Forty of the samples (36 coal and 4 coal-associated rock) are from the Rosebud bed and 21 samples (all coal) are from the McKay bed. The McKay bed is between 5.5 and 18.6 m. below the Rosebud bed. The samples were collected from the Big Sky Mine and from 13 core holes in sec. 1, 2, and 27, T. 1 N., R. 41 E.; sec. 23 and 35, T. 2 N., R. 41 E.; and in sec. 1, 3, 5, 9, 15, and 16, T. 1 N., R. 40 E. The location of the sample collection area is shown in figure 1. Brief descriptions of all 61 samples are listed in table 1 and locations of sampling sites are shown in figure 2. Estimated strippable coal resources for the Rosebud bed in this area exceed 1,305 metric tons (1,439 million short tons) (Matson and Blumer, 1974). There are currently no estimates of coal resources for the McKay bed from this area. Analyses of samples D172034 through D172051 have previously been published in Swanson and others (1976) and are included here in order to provide a more complete data listing. For additional information on sulfur and trace element contents in the Rosebud and McKay coal beds, see Chadwick, Woodriff and others (1975) and Chadwick, Rice and others (1975).
Audio-magnetotelluric data log and station-location map for the Silver Star Hot Springs area, Montana
During a period of 3 days, 22 audio-magnetotelluric (AMT) soundings were made in the area of the Silver Star Hot Springs, Mont. (fig. 1). These soundings were made to assess the geothermal potential along a northern trend of. hot springs from New Biltmore Hot Springs north to Broadwater Hot Springs, Mont. Scalar resistivities from the data log (table 1) show that thermal waters have probably altered the Cenozoic basin fill to the northeast for at least 4-5 km. Leakage of the geothermal system to the surface is probably taking place along a range-front fault at the contacts between the Precambrian metamorphics on the west and the Cenozoic basin fill on the east. Any potential geothermal system would probably be in the area near the existing hot springs or within a few kilometers to the north or northeast.
Audio-magnetotelluric data log and station-location map for the Ennis Hot Springs area, Montana
Four days were spent collecting 20 audio-magnetotelluric (AMT) soundings in the area of the Ennis Hot Springs, Mont. (fig. 1). These soundings were made to assist in a regional evaluation of the geothermal potential of the Ennis Hot Springs area. Scalar resistivities from the data log (table 1) are indicative of thermal water altering the Quaternary alluvium to the southeast. The alteration extends over an area of 1.5 km by 4 km. The geothermal system is probably along a north-south range fault between the Precambrian gneiss and the Tertiary gravels. The scalar resistivities also indicate a northwest trend that may be an intersecting fault. Therefore any geothermal potential would probably be in the area near the existing hot spring, with a possible extent to the northwest of 1 km and to the southeast some 3 km.
Principal facts for gravity stations of the Broadwater, Montana geothermal area
On October 31, November 1 and 3, 1978, forty-eight gravity stations were established near Helena, in the Broadwater geothermal area, west-central Montana (fig. 1).
Telluric profile and location map for the Broadwater Hot Springs area, Montana
A telluric profile (E-field ratio telluric method) was made in the vicinity of the Broadwater Hot Springs, Montana to help assess the geothermal potential of the area. The method and equipment used is similar to that described by Beyer (1977). For this survey the recording bandwidth was 0.025 Hz centered at 0.033 Hz (30 sec period) and a dipole length of 500 meters was used.
Telluric profiles and location map for the Ennis Hot Springs area, Montana
No abstract available.
Water resources of the southern Powder River area of southeastern Montana
The southern Powder River area comprises about 2,230 square miles in southeastern Montana. Sedimentary rocks beneath this area range in age from Cambrian to Holocene and attain a maximum thickness of about 12,000 feet. Rocks exposed in the study area range in age from Late Cretaceous to Holocene. Water for domestic, stock, and public use in the southern Powder River area is available from the Fox Hills-lower Hell Creek aquifer and the upper part of the Hell Creek Formation, both of Late Cretaceous age, and the Fort Union Formation of Paleocene age. Water for industrial use might be available from the Madison Group of Mississippian age. Where adequate quantities are available, water from the Madison Group is suitable for irrigation. Water from alluvium of Holocene and Pleistocene age along the Powder River is marginally suitable for irrigation, and surface water from the Powder River is suitable for irrigation, except during periods of low flow. The Madison Group is a sequence of carbonate rocks that underlies the entire study area and ranges in thickness from 800 to 1,500 feet. Depth to the top of the group is about 4,000 feet in the southeastern part of the area and as much as 9,000 feet in the southwestern part. Water-supply wells at the Bell Creek oil field in the southeastern part of the study area flow as much as 1,300 gal/min (gallons per minute). Oil-field water from this area contains calcium, magnesium, and sulfate as major ions, and contains less than 1,000 mg/L (milligrams per liter) dissolved solids. The Fox Hills-lower Hell Creek aquifer is predominantly sandstone interbedded in part with sandy shale and siltstone. The aquifer crops out in the eastern part of the study area and dips generally westward beneath the land surface at about 40 to 200 feet per mile. Wells in the Fox Hills-lower Hell Creek aquifer range in depth from 25 feet in the outcrop area to 1,358 feet between the Powder and Little Powder Rivers. Measured well yields range from 3 to 200 gal/min. Many flowing wells along the principal rivers yield as much as 20 gal/min. The water contains calcium, magnesium, and bicarbonate or sulfate as major ions in the outcrop area. Downgradient, sodium and bicarbonate are predominant. The dissolved-solids concentration ranges from 261 to 2,230 mg/L. The upper part of the Hell Creek Formation consists of interbedded shale, siltstone, claystone, and sandstone. Wells in the upper part of the Hell Creek are as deep as 1,045 feet. Flowing wells along the Powder and Little Powder Rivers yield as much as 40 gal/min, but pumped wells generally yield less. The water quality is similar to that of the Fox Hills-lower Hell Creek aquifer. The dissolved-solids concentration ranges from 236 to 1,580 mg/L. The Fort Union Formation consists of interbedded sandstone, siltstone, shale, and coal. The formation crops out in the western three-fourths of the study area and is about 2,100 feet thick in the southwestern part. Wells tapping this unit range in depth from 120 to 1,100 feet. Wells and springs are reported to yield as much as 20 gal/min; many wells flow. The upper part of the formation is a major aquifer west of the Powder River valley. The water contains calcium, magnesium, sodium, bicarbonate, and sulfate as the major ions in most any relative proportion. The dissolved-solids concentration ranges from 541 to 2,160 mg/L. Alluvium is unconsolidated deposits of interbedded clay, silt, sand, and gravel, mostly along the river valleys. Maximum measured thicknesses of these deposits were 62 and 55 feet along the Powder and Little Powder Rivers, respectively. Several irrigation wells drilled in the alluvium along the Powder River have reported yields of as much as 900 gal/min. Water contains calcium, magnesium, and sulfate as major ions. The dissolved-solids concentration of two water samples from the Powder River valley was 1,780 and 2,240 mg/L. The only perennial streams are the Powder and Little Powder Rivers. Based on available streamflow records, the mean-annual discharge of the Powder River at Moorhead, in the southwestern part of the area, is 448 cubic feet per second; discharge varies from 0 to 23,000 cubic feet per second. Mean-annual discharge of the Little Powder River near Broadus, in the north-central part of the area, is 31 cubic feet per second; discharge varies from 0 to 2,440 cubic feet per second. Water from the Powder River normally contains calcium and sulfate as the major ions. Dissolved-solids concentration ranges from 20 to 3,460 mg/L.
Water-resources investigations of the U.S. Geological Survey in Montana, October 1978 through September 1979
The report describes water-resources investigations of the U.S. Geological Survey in Montana, October 1978 through September 1979. Programs consist of (1) collecting hydrologic data on a continuing basis, (2) conducting water-resources appraisals of surface and ground water, (3) conducting supportive research in hydrology and related fields, (4) disseminating water data and results of investigations to the public, (5) coordinating acquisition of water data by Federal agencies, and (6) providing technical assistance in hydrologic fields to other government agencies.
Chemical analyses of coal from the Tongue River Member of the Fort Union Formation, Moorhead and southeastern part of the northward extension of the Sheridan coal fields, Powder River and Big Horn counties, Montana
As part of a continuing program by the U.S. Geological Survey to collect and chemically analyze representative samples of U.S. coals, 83 samples were collected from 23 core holes in the Paleocene Tongue River Member of the Fort Union Formation in Big Horn and Powder River counties, Montana. These holes are located in the Montana part of the Powder River coal region, specifically in the western part of the Moorhead coal field and on the eastern margin of the Northward Extension of the Sheridan coal field (fig. 1)
Coal resource and coal quality of Pumpkin Creek EMRIA site, Powder River County, Montana: With a section on chemical analysis
The Pumpkin Creek EMRIA site, an area of about 94 square miles, is located mainly in the southwestern part of the Coalwood coal field on the slightly westward dipping beds of the Tongue River Member of the Paleocene Fort Union Formation in Powder River County, Montana. Three coal beds, A, Sawyer, and Mackin-Walker, were evaluated by 32 drill holes. Coal resources--measured, indicated, and inferred--within the site and in beds more than 5 feet thick are 191,660,000 short tons, 1,356,950,000 short tons, and 34,400,000 short tons, respectively. The coal has an apparent rank of lignite A as shown by the analyses of 17 core samples. The average Btu value of 15 core samples of the Sawyer from the site on the as-received basis is 6,970, average ash content is 6.8 percent, and average sulfur content is 0.4 percent. A comparison of the analyses of samples from the Sawyer coal bed with other analyses of Powder River region coal samples shows that moisture, hydrogen, and oxygen contents are significantly higher, and volatile matter, fixed carbon, carbon, nitrogen, and total sulfur contents and heat of combustion are significantly lower in the Sawyer bed samples. A statistical comparison of the elemental compositions of the two sample groups shows that the Sawyer bed has significantly higher contents of B, Ba, Mn, Nb, U, Y, and Yb and significantly lower contents of Be, Co, Cr, Cu, Ni, Pb, Sc, Se, and Th. The sample of the lower split of the Sawyer bed (bed A) in drill hole PWW8 has a relatively high sulfur content of 1.7 percent, and presumably would not be mined with the rest of the Sawyer. The Mackin-Walker has a Btu value of 7,220, an ash content of 6.9 percent, and a sulfur content of 1.0 percent.