Wasatch Plateau Coal Research Articles

Interactions between fossil resin and coal in the presence of anionic and cationic surfactants

Interaction forces between resin spheres and a polished coal surface were measured by atomic force microscopy (AFM). Spherical resin particles, used for these measurements, were obtained from naturally occurring fossil resin present in Wasatch Plateau coal (Utah, USA) using a special preparation technique. Force measurements were made in solutions of sodium dodecyl sulfate and dodecylamine hydrochloride as a function of concentration. Electrophoresis and transmittance studies of coal and resin suspensions were performed for the same conditions as for the force measurements. As expected, for both surfactants, repulsive forces were observed. However, in 10 −5 M and 10 −4 M DDAH repulsive forces were not observed at distances from the surface beyond 10 nm. This concentration is very close to the point of zero charge (pzc) for resin and coal as determined by electrophoresis measurements. The force/radius values versus separation distance were plotted against concentration values as a 3D map. The trends observed were in very good agreement with electrophoresis and transmittance plots. The results show that the pzc and suspension stability can be estimated from AFM force measurements even for non-ideal surfaces, as typically encountered in many industrial processes.

95/00069 The chemistry of ozone conditioning in the selective flotation of macroscopic fossil resin from Utah Wasatch Plateau coal

95/00069 The chemistry of ozone conditioning in the selective flotation of macroscopic fossil resin from Utah Wasatch Plateau coal

The Chemistry of Ozone Conditioning in the Selective Flotation of Macroscopic Fossil Resin from Utah Wasatch Plateau Coal

Ozone conditioning can be used for the selective flotation of macroscopic fossil resin (resinite) from coal by treatment of the resin/coal suspension for an appropriate period of time prior to flotation. In this way, a significant improvement in resin separation efficiency can be achieved, but the chemistry of ozone reactions and its influence on particle behavior have not been reported. The improvement in the selective fossil resin flotation by ozone conditioning has been found to be due to (1) the improved depression of fine coal particles, which is evidenced from contact angle measurements, chemical analysis, and FTCR spectroscopic examination; and (2) the improved dispersion of the resin/coal suspension in which the coagulation between resin and coal particles in suspension was significantly reduced by ozonation as evidenced by optical microscopic observation.

A study of hexane/toluene extraction of fossil resin types from the Utah Wasatch Plateau coal

Four fossil resin types from the Wasatch Plateau coal field of central Utah were distinguished by their colour—yellow, amber, light-brown and dark brown—and were physically isolated by hand sorting. These resin types were subjected to physical/chemical characterization, petrographic examination, and hexane/toluene extraction. The solvent extracted fractions were then subjected to pyrolysis gas chromatography/electron impact mass spectrometry analysis and FT-i.r. spectroscopic examination. The extraction rate by both hexane and toluene follows the order: yellow > amber > light brown > dark brown. These resins were found to be composed mainly of aliphatic components, partially aromatized multicyclic terpenoids and a few oxygen functional groups (mostly -COOH) with molecular weight and aromaticity increasing in the following order: yellow resin < amber resin < light brown resin < dark brown resin. Hexane-purified resin from these four resin types closely resembles the properties of physically separated yellow resin which is of significant value in the printing ink industry. The nature of the resinite coloration is discussed, based on the experimental results.

Analysis of Selective Resinite Flotation from Wasatch Plateau Coal by pH Control

It has been found that selective resinite flotation from Wasatch Plateau coal can be achieved at high pH. For example, a high grade resin concentrate (>70% resin) was obtained at an excellent recovery (>90%) by single-stage flotation above pH 12 from a feed containing only 7.2% resin. This rougher concentrate was then cleaned to produce a cleaner concentrate containing >90% resin. The flotation results thus obtained by pH control can be explained to be due to: (1) improved dispersion of the resinite/coal suspension as evidenced by microscopic observation, electrokinetic behavior, and sedimentation phenomena: and (2) improved depression of coal particles; their hydrophilic state being stabilized by surface precipitation and/or adsorption of calcium species at higher pH values as determined by FTIR and XPS spectroscopic analysis.

Coal-bed Methane Exploration and Development in Utah

Utah has joined the ranks of coal bed-methane producing states and has active coal-bed methane exploration. The targets are coals in the Cretaceous Blackhawk Formation and the slightly older Ferron Sandstone Member of the Mancos Shale. In 1990, Cockrell Oil Corporation completed five test wells in the Book Cliffs coal field north of the town of Price. These wells produce between 51 and 196 thousand ft[sup 3]/day per well from Castlegate coals in the middle part of the Blackhawk Formation at depths of 4200 to 4400 ft. The wells have been producing for over a year and through July 1992 had cumulatively produced 201 million ft[sup 3] of gas and 1.11 million bbl of water. The daily production of gas has been increasing and the daily production of water decreasing. Due to the success of these initial wells, a large, aggressive drilling program covering 21,450 ac is planned to develop the new gas field. Pacific Gas and Electric, which acquired the property, plans to drill over 120 wells to depths from 3000 to 7600 ft on 160-ac spacing to test multiple coals seams in the Blackhawk Formation. Projected average production per well is estimated at 300 to 320 thousand ft[supmore » 3]/day during the first 5 yr of production, with total field production estimated to reach 62 million ft[sup 3]/day by 1997. Several other areas are being explored for coal-bed methane including (1) additional Blackhawk tests east and west of the producing area and (2) Ferron tests in the northern Emery and northern Wasatch Plateau coal fields. These are all smaller programs of 3 to 10 wells. Recent calculations by the Utah Geological Survey show 8.3 to 10.6 tcf of coal-bed methane for four Uinta basin coal fields. This value is two to three times larger than previously estimated, but is still considered conservative. The Book Cliffs and the Emery coal fields have the best methane potential.« less

Chemical composition and origin of fossil resins from Utah Wasatch Plateau coal

In order to arrive at a more detailed chemical description of fossil coal associated resins we need to distinguish between micropetrographic, organic geochemical and process technological definitions, each of which may encompass varying quantities of constituents unrelated to fossil tree resins. New information on composition and origin of Utah Wasatch Plateau coal resins obtained by Curie-point pyrolysis/evaporation in combination with iso-butane chemical ionization mass spectrometry, as presented in this paper, points to the presence of four more or less distinct resin components: (1) a sesquiterpenoid polymer; (2) sesqui- and triterpenoid monomers and dimers; (3) a suite of triterpenoid alcohols, ketones and acids; and (4) a series of increasingly aromatized hydrocarbons with naphthalene and picene type skeletons. Moreover, a strong similarity is found between the composition of recent dammar resin and fossil Wasatch Plateau coal resins indicating a possible Angiosperm (fam. Dipterocarpaceae) origin of these Upper Cretaceous coal resins. Some of the technological implications of these findings and the consequent need for a more precise chemical definition and nomenclature are discussed.