128 research outputs found
Mineralogy and prospect of noble metals of gold-bearing ore breccias from ore fields of polymetallic deposits of Ore Altai
The object of the present study are the ore-bearing breccias of the worked-out lower-middle Devonian gold-silver barite-polymetallic Zmeinogorsky deposit belonging to the cognominal ore district and the conserved massive sulfide Chekmar deposit belonging to the Leninogorsk ore district. Both ore districts occupy an adjacent position within the northeastern depression zone of the Ore Altai megatrough. A brief structural and geological description of near-fault ore-bearing breccias, which developed within the peripheral parts of the deposits, is given. Analysis of petrographic composition of breccia fragments and their cementing material allowed to define barite-quartzite breccias of the Zmeinogorsky deposit and pyritized adularia-quartz metasomatites formed upon acidic igneous rocks and greenschists of the Chekmar deposit. Results of mineralogical studies with use of raster electron microscope show that there are ore minerals microinclusions in the detrital material and cement of breccias. Barite-quartzite breccias of Zmeinogorsk deposit contain barite, galena, Hg and Sb containing polymineral formations, tetrahedrite-boulangerite, bromargyrite, leucoxene. Microquartzites of these breccias mostly consist of quartz. Chekmar deposit ore breccias detrital material contains pyrite, barite, arsenopyrite, galena, sphalerite, zircon, titanite, leucoxene and REE minerals. Quartzitic compound of these breccias is cryptocrystalline and consists of quartz and adularia with admixtures of sericite and pyrite. Due to results obtained by use of SEM it was stated that barite, sulfides and sulfosalts of breccias contain noticeable amounts of dissipated Au, Pd, Pt, Ir. ICP-MS results confirm that studied ore breccias contain such noble metals as Au, Ag, Pd, Pt. Moreover, noble metals contents in Zmeinogorsk deposit breccias reach industrial standards while noble metals of Chekmar deposit ores can be extracted along with the processing of basic massive sulfide ores. Further study of ore breccias is important as these breccias can be considered as a noble metals containing subformation among polymetallic ores of Ore Altai
Calculating the strenth of the lifting assembly in non-forming moulding slabs with mounting tabs at the ends of product
The calculations of the strength of the lifting assembly are made for non-forming moulding slabs with the installation of mounting tabs into the ends of the product. The data are obtained on the strength of the lifting unit, the required diameter of the hinge pin, the length of the anchoring loop
Calculating the strenth of the lifting assembly in non-forming moulding slabs with mounting tabs at the ends of product
The calculations of the strength of the lifting assembly are made for non-forming moulding slabs with the installation of mounting tabs into the ends of the product. The data are obtained on the strength of the lifting unit, the required diameter of the hinge pin, the length of the anchoring loop
To roof frame optimization
This paper shows the design criteria truss, identified optimization problem for such structures. Shows an example of calculation for optimization lattice girder supporting roof trusses with a triangular lattice in order to find the most efficient configuration of the body structure
U-Pb geochronology of subvolcanic and pyroclastic formations of the Zmeinogorsk barite-polymetallic deposit (Rudny Altai)
Schemes of Zmeinogorsk ore field structure made in 1996, 1960 and 1949 have been analyzed. The schemes differ from each other in contents and prospecting trends. This study is based on the 1949 scheme, made on the basis of the results of extensive mining and drilling operations. Based on the analysis of stratigraphy, LA-Q-ICP-MS dating results by U-Pb method, rocks composition, plicative and disjunctive dislocations of sedimentary, volcanic and subvolcanic formations, as well as their relationship, an updated scheme of Zmeinogorsk ore field structure is suggested. It belongs to rhyolite dome-type, which is also charactered to the neighboring Leninogorsk ore distric
Statistical Mechanics of Vibration-Induced Compaction of Powders
We propose a theory which describes the density relaxation of loosely packed,
cohesionless granular material under mechanical tapping. Using the compactivity
concept we develope a formalism of statistical mechanics which allows us to
calculate the density of a powder as a function of time and compactivity. A
simple fluctuation-dissipation relation which relates compactivity to the
amplitude and frequency of a tapping is proposed. Experimental data of
E.R.Nowak et al. [{\it Powder Technology} 94, 79 (1997) ] show how density of
initially deposited in a fluffy state powder evolves under carefully controlled
tapping towards a random close packing (RCP) density. Ramping the vibration
amplitude repeatedly up and back down again reveals the existence of reversible
and irreversible branches in the response. In the framework of our approach the
reversible branch (along which the RCP density is obtained) corresponds to the
steady state solution of the Fokker-Planck equation whereas the irreversible
one is represented by a superposition of "excited states" eigenfunctions. These
two regimes of response are analyzed theoretically and a qualitative
explanation of the hysteresis curve is offered.Comment: 11 pages, 2 figures, Latex. Revised tex
Experimental and computational studies of jamming
Jamming is a common feature of out of equilibrium systems showing slow
relaxation dynamics. Here we review our efforts in understanding jamming in
granular materials using experiments and computer simulations. We first obtain
an estimation of an effective temperature for a slowly sheared granular
material very close to jamming. The measurement of the effective temperature is
realized in the laboratory by slowly shearing a closely-packed ensemble of
spherical beads confined by an external pressure in a Couette geometry. All the
probe particles, independent of their characteristic features, equilibrate at
the same temperature, given by the packing density of the system. This suggests
that the effective temperature is a state variable for the nearly jammed
system. Then we investigate numerically whether the effective temperature can
be obtained from a flat average over the jammed configuration at a given energy
in the granular packing, as postulated by the thermodynamic approach to grains.Comment: 20 pages, 9 figure
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