This thesis presents the results of an investigation of factors which influence the geotechnical properties of frozen mine backfill (FMB). FMB has extensive application potential for mining in permafrost areas. The uniaxial compressive strength (UCS) of hardened backfill is often used to evaluate mine backfill stability. However, the deformation behaviour and stiffness of the FMB are also key design properties of interest. In this thesis, uniaxial compressive tests were conducted on FTB and FCPB samples. Information about the geotechnical properties of FMB is obtained. The effects of FMB mix components and vertical compression pressure on the geotechnical properties of FMB are discussed and summarized. An optimum total water content of 25%-35% is found in which the strength and the modulus of elasticity of the FTB are 1.4-3.2 MPa and 35-58 MPa, respectively. It is observed that a small amount (3-6%) of cement can significantly change the geotechnical properties of FTB.

This thesis presents the results of an investigation of factors which influence the geotechnical properties of frozen mine backfill (FMB). FMB has extensive application potential for mining in permafrost areas. The uniaxial compressive strength (UCS) of hardened backfill is often used to evaluate mine backfill stability. However, the deformation behaviour and stiffness of the FMB are also key design properties of interest. In this thesis, uniaxial compressive tests were conducted on FTB and FCPB samples. Information about the geotechnical properties of FMB is obtained. The effects of FMB mix components and vertical compression pressure on the geotechnical properties of FMB are discussed and summarized. An optimum total water content of 25%-35% is found in which the strength and the modulus of elasticity of the FTB are 1.4-3.2 MPa and 35-58 MPa, respectively. It is observed that a small amount (3-6%) of cement can significantly change the geotechnical properties of FTB.

This thesis presents the results of an investigation of factors which influence the geotechnical properties of frozen mine backfill (FMB). FMB has extensive application potential for mining in permafrost areas. The uniaxial compressive strength (UCS) of hardened backfill is often used to evaluate mine backfill stability. However, the deformation behaviour and stiffness of the FMB are also key design properties of interest. In this thesis, uniaxial compressive tests were conducted on FTB and FCPB samples. Information about the geotechnical properties of FMB is obtained. The effects of FMB mix components and vertical compression pressure on the geotechnical properties of FMB are discussed and summarized. An optimum total water content of 25%-35% is found in which the strength and the modulus of elasticity of the FTB are 1.4-3.2 MPa and 35-58 MPa, respectively. It is observed that a small amount (3-6%) of cement can significantly change the geotechnical properties of FTB.

Call number: LD2668 .T4 1961 S77

Call number: LD2668 .T4 1964 C288 / Master of Science

LD2668 .T4 1965 W916 / Master of Science

Call number: LD2668 .T4 1979 S34 / Master of Science

The effects of freeze-drying and flake freezing of surimi on biochemical and physical properties as affected by various storage conditions were examined. Using three cooking parameters shear stress and strain values were evaluated to measure gelation properties of surimi gels. Stress values increased up to 3 months and then decreased substantially as storage time was extended. In general, strain values decreased substantially over time, however, freeze-dried surimi kept in the freezer at - 18°C did not change during 9 months of storage. Overall, color decreased during storage and b* values of the freeze-dried surimi kept at room temperature increased significantly. Salt extractable proteins decreased while dimethylamine increased. Electrophoretic patterns, however, did not show any apparent damage to the MHC due to frozen storage and/or proteolysis (with 60°C incubation) until the 9th month of storage. At 9 months, a reduction of the MHC was observed and the lower molecular weight bands were more intense. Freeze-dried samples stored in the freezer maintained the highest quality for the duration of the 9 month study. Low temperature storage is important for retaining good functionality in freeze-dried surimi. The effects of cross-section diameter on shear stress and strain and effects of individual variation in measuring diameter were studied. Gelation properties of surimi using milled and molded gels were compared. The possibility of skin formation using various cook times was also evaluated. Shear stress values were significantly affected by diameter accuracy, whereas the effect was not as significant for shear strain values. Individual variation in measurement was also greatly noted. Molded gels resulted in significantly lower strain values than milled samples, whereas stress values were significantly higher in molded gels than in milled gels. Using a lechitin-based spray appeared to eliminate skin formation on all samples. / Graduation date: 2001

Large amounts of plant tissue are used in the production of many canned, frozen and dried foods. Some of this material is unsatisfactory in appearance and texture, despite careful processing from high quality raw materials. In the present study, the changes induced in soft fruits by controlled heating and freezing treatments were of prime concern. Strawberries and tomatoes were canned and frozen in 60° B sucrose syrup, stored for 3-6 months and examined by physical and chemical methods. Measurements of the texture, pectins, hemicelluloses, cellulose, nitrogen, ash and ash constituents, were made on raw, frozen and canned samples. The tissues were sliced, macerated with 0.4 percent sodium hexametaphosphate, and screened. The cell suspensions were dialysed and stored at 35°F, with toluene as a preservative. The cell suspensions were analyzed similarly to the tissue samples, and the reactivity of the cell suspensions with sugars and electrolytes was investigated. The results indicated the following conclusions: 1) No significant difference was found between the effects of canning and freezing on the texture of the fruits, as determined by the Shear Press, although major differences were found between the fresh and processed samples. 2) Drained weights were lower when the fruits were canned than when frozen, especially in the strawberries. 3) Histological changes brought about by the treatments were more marked in the frozen than in the canned fruits. Freezing caused severe breakage of cell walls, plus some cell separation, whereas canning tended to cause more shrinkage of cells without much breakage or separation. Adhesion between cells was increased in the heated packs. Damage to cells increased as cell size increased. The study showed that more emphasis should be placed on selecting varieties of fruits for processing which have a smaller mean cell size, and thicker cell walls. 4) Aqueous suspensions of parenchyma cells were found to be a useful means of studying the several mechanisms involved in textural and drained weight changes. 5) No sorption affinity was found between dialysed, depectinized parenchyma cells and sucrose or glucose. 6) Dialysed cells were negatively charged, highly hydrated, and formed viscous suspensions at low concentrations. 7) The addition of small amounts of cations, particularly H⁺ ion and Al⁺⁺⁺ ion, precipitated cell suspensions, by suppressing the ionization of the carboxyl group or by salt formation. 8) A new hypothesis was proposed which assigned an important role to the acids and other electrolytes of fruits, in governing the textural and drained weight characteristics of such products. It was proposed that the quantity of acids and other electrolytes which become distributed throughout the cell during processing, causes a reduction of cell hydration including a shrinkage of cell walls, which could be partially reversed during subsequent storage. / Graduation date: 1963

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