The Investigation of Different Variables in the Assaying of Silver Cyanide Solution

The assaying of gold and silver cyanide solutions is by no means new. The first method of analysis which is given in the literature is an evaporation method by S. B. Christy in 1896. However, the fire assaying of gold and silver dates further back than this. There is a method of fire assaying for gold and silver given in literature as early as 1556 in Georgius, Agricola’s De Re Metallica book.

The Investigation of Different Variables in the Assaying of Silver Cyanide Solutions

The cyanide method of extraction of gold and silver from their ores is extensively used in the United States and elsewhere. It is becoming increasingly more important in its use as the mining of lower grade deposits continues.

The Theory of Alloy Deposition and The Effect of a Rotating Cathode Upon Such Deposition, with Special Attention to the Possibility of Depositing Sterling Silver

In the past few years a great deal of atten­tion has been given to the electrodeposition of alloys. For the main part, this investigation has been of scien­tific interest only; but in a few instances, such work has attained commercial importance.

The Beneficiation of Montana Silver Star Chromite Ore

It is known that there are large deposits of chromium ore in Stillwater and Carbon Counties in South-Central Montana. The late James F. Kemp of Columbia University, stated in 1928, that these were the largest chromium deposits in the United States and probably in the world, although they were not considered of commercial grade as compared with foreign ores.

Chromite Deposits Near Red Lodge and Silver Star, Montana

The Red Lodge and Silver Star chromite deposits of Montana have stimulated much interest during periods of war. The Red Lodge deposit is 25 miles southwest of Red Lodge which is also the nearest railroad point. Several workings are scattered throughout the area, exposing lense-like ore bodies averaging 33% chrome oxide. Silver Star is a much smaller deposit 5 miles west of Silver Star, Montana, which is its nearest rail­road point. Lenses of chromite are exposed by pits and trench­es, which average approximately 36% chromic oxide.

Revegetation and Bird Trends, Silver Bow Creek Superfund Remediation and Restoration

Silver Bow Creek runs approximately 25 miles from Butte to Warm Springs, where it joins Warm Springs Creek to form the Clark Fork River. This historic creek was terribly contaminated with mine wastes around the turn of the 20th century, leaving many "slickens" that persisted into the 21st century, when it became a Superfund remediation project. More than 5.5 million cubic yards of stream-deposited mine waste have been removed and 1,650 acres revegetated. Chief contaminants are copper, zinc, and arsenic, but acidic soils are often equally or more limiting to plants. The stream was relocated, and mine wastes were replaced with biologically inert cover soil. Richard A. Prodgers is currently a plant ecologist with Bighorn Environmental Sciences in Dillon, Montana.

Integration of QUAL2Kw and ArcGIS for Silver Bow Creek, Montana

The purpose of this project is to take preliminary steps towards the development of a QUAL2Kw model for Silver Bow Creek, MT. These preliminary steps include initial research and familiarization with QUAL2Kw, use of ArcGIS to fill in geospatial data gaps, and integration of QUAL2Kw and ArcGIS. The integration involves improvement of the QUAL2Kw model output through adding functionality to the model itself, and development of a QUAL2Kw specific tool in ArcGIS. These improvements are designed to help expedite and simplify the viewing of QUAL2Kw output data spatially in ArcGIS as opposed to graphically within QUAL2Kw. These improvements will allow users to quickly and easily view the many output parameters of each model run geographically within ArcGIS. This will make locating potential problem areas or “hot spots” much quicker and easier than interpreting the QUAL2Kw output data from a graph alone. The added functionality of QUAL2KW was achieved through the development of an excel Macro, and the tool in ArcGIS was developed using python scripting and the model builder feature in ArcGIS.

Fluorite Near Silver Bow, Montana

The wartime demand for fluorspar has caused renewed interest in fluorite deposits. Near Silver Bow, Montana, a deposit of massive, coarsely crystalline fluorspar, which has not been described in the literature, has attracted the atten­tion of the United States Geological Survey.

Flotation Concentration of a Montana Lead-Zinc-Silver-Ore

The Mike Horse mine, in the Huddelston mining district, is fifty-two miles northwest of Helena, Montana. The mine was discovered in 1898 by Joseph Heitmiller. There was only minor production from the date of discovery until 1915; the main drawback being lack of good road.

Ultrasonographic features of PMEL17 ( Silver ) mutant gene-associated multiple congenital ocular anomalies (MCOA) in Comtois and Rocky Mountain horses

OBJECTIVE: (1) To describe the ultrasonographic appearance of multiple congenital ocular anomalies (MCOA) in the eyes of horses with the PMEL17 (Silver) mutant gene. (2) To compare the accuracy of B-mode ocular ultrasound to conventional direct ophthalmoscopy. ANIMALS STUDIED: Sixty-seven Comtois and 18 Rocky Mountain horses were included in the study. PROCEDURES: Horses were classified as being carriers or noncarriers of the PMEL17 mutant allele based on coat color or genetic testing. Direct ophthalmoscopy followed by standardized ultrasonographic examination was performed in all horses. RESULTS: Seventy-five of 85 horses (88.24%) carried at least one copy of the Silver mutant allele. Cornea globosa, severe iridal hypoplasia, uveal cysts, cataracts, and retinal detachment could be appreciated with ultrasound. Carrier horses had statistically significantly increased anterior chamber depth and decreased thickness of anterior uvea compared with noncarriers (P < 0.05). Uveal cysts had a wide range of location and ultrasonographic appearances. In 51/73 (69.86%) carrier horses, ultrasound detected ciliary cysts that were missed with direct ophthalmoscopy. CONCLUSIONS: In this study, ultrasonography was useful to identify uveal cysts in PMEL17 mutant carriers and to assess anterior chamber depth.

Phylogeography of silver pheasant (Lophura nycthemera L.) across China: aggregate effects of refugia, introgression, and riverine barriers

The role of Pleistocene glacial cycles in forming the contemporary genetic structure of organisms has been well studied in China with a particular focus on the Tibetan Plateau. However, China has a complex topography and diversity of local climates, and how glacial cycles may have shaped the subtropical and tropical biota of the region remains mostly unaddressed. To investigate the factors that affected the phylogeography and population history of a widely distributed and nondeciduous forest species, we analysed morphological characters, mitochondrial DNA sequences and nuclear microsatellite loci in the Silver Pheasant (Lophura nycthemera). In a pattern generally consistent with phenotypic clusters, but not nominal subspecies, deeply divergent mitochondrial lineages restricted to different geographic regions were detected. Coalescent simulations indicated that the time of main divergence events corresponded to major glacial periods in the Pleistocene and gene flow was only partially lowered by drainage barriers between some populations. Intraspecific cytonuclear discordance was revealed in mitochondrial lineages from Hainan Island and the Sichuan Basin with evidence of nuclear gene flow from neighbouring populations into the latter. Unexpectedly, hybridization was revealed in Yingjiang between the Silver Pheasant and Kalij Pheasant (Lophura leucomelanos) with wide genetic introgression at both the mtDNA and nuclear levels. Our results highlight a novel phylogeographic pattern in a subtropical area generated from the combined effects of climate oscillation, partial drainage barriers and interspecific hybridization. Cytonuclear discordance combined with morphological differentiation implies that complex historical factors shaped the divergence process in this biodiversity hot spot area of southern China.

In vitro staining effects of stannous fluoride and sodium fluoride on ceramic material.

STATEMENT OF PROBLEM: Long-term fluoride application on the teeth of patients receiving radiation therapy for head and neck tumors results in excessive staining and roughening of ceramic restorations. PURPOSE: The purpose of this in vitro study was to compare the staining effects of 2 fluoride treatments on ceramic disks by simulating 1 year of clinical exposure at 10 minutes per day. In addition, 2 different surface preparations were tested. MATERIAL AND METHODS: Eighty ceramic disks (IPS Empress), 20 x 2 mm, were fabricated. Half of the disks were glazed, and the remaining disks were polished. All disks were brushed for 3 minutes with a soft-bristle power toothbrush and mild dentifrice (baseline) and were immersed in 1 of the 2 fluoride products (0.4% SnF(2), Gel-Kam Gel, or 1.1% NaF, Prevident 5000) for 10 days (n=20). Means and standard deviations of color change (Delta E), surface roughness (Ra, um), and surface gloss (GU) of the ceramic material were measured with a reflection spectrophotometer, a profilometer, and a gloss meter, respectively, at baseline and after fluoride treatment. Two- and 3-way ANOVA (alpha=.05), with surface preparation (polished vs. glazed) and fluoride treatment (0.4% SnF(2) or 1.1% NaF) as independent variables and condition (baseline vs. after fluoride treatment) as a repeated measure, was used to analyze the data. Fisher's PLSD intervals (alpha=.05) were calculated for comparisons among the means. RESULTS: The polished specimens had significantly higher Delta E values, significantly higher surface gloss values, and significantly lower surface roughness values than the glazed specimens before fluoride treatment (P<.001). After both fluoride treatments, ceramic disks exhibited significantly higher surface roughness values when polished and significantly lower surface gloss values when glazed or polished (P<.001). The glazed specimens presented significantly higher surface roughness (P<.001) and lower surface gloss values (P<.001) when treated with 0.4% SnF(2) as compared to NaF. For the polished specimens, there was no significant difference in surface roughness and surface gloss values between the 2 fluoride treatments. CONCLUSIONS: Use of 0.4% SnF(2) and 1.1% NaF gels, in vitro, caused significant color change in the polished IPS Empress ceramic disks. Polishing of the ceramic surface before immersion in either fluoride agent caused the ceramic tested to be more resistant to etching by the 2 solutions tested. The NaF caused less deterioration of the porcelain surface and was less stain inducing than SnF(2).