At present, with the increase of production capacity and the promotion of production, the reserves
of most mining enterprises under the original industrial indexes are rapidly consumed, and the full
use of low-grade resources is getting more and more attention. If mining enterprises want to make
full use of low-grade resources simultaneously and obtain good economic benefits to strengthening
the analysis and management of costs is necessary. For metal underground mines, with the gradual
implementation of exploration and mining projects, capital investment and labor consumption are
dynamic and increase cumulatively in stages. Consequently, in the evaluation of ore value, we should
proceed from a series of processes such as: exploration, mining, processing and the smelting of
geological resources, and then study the resources increment in different stages of production and the
processing. To achieve a phased assessment of the ore value and fine evaluation of the cost, based on
the value chain theory and referring to the modeling method of computer integrated manufacturing
open system architecture (CIMOSA), the analysis framework of gold mining enterprise value chain is
established based on the value chain theory from the three dimensions of value-added activities, value
subjects and value carriers. A value chain model using ore flow as the carrying body is built based on
Petri nets. With the CPN Tools emulation tool, the cycle simulation of the model is carry out by the
colored Petri nets, which contain a hierarchical structure. Taking a large-scale gold mining enterprise
as an example, the value chain model is quantified to simulate the ore value formation, flow, transmission
and implementation process. By analyzing the results of the simulation, the ore value at different
production stages is evaluated dynamically, and the cost is similarly analyzed in stages, which can improve mining enterprise cost management, promote the application of computer modeling and
simulation technology in mine engineering, more accurately evaluate the economic feasibility of ore
utilization, and provide the basis for the value evaluation and effective utilization of low-grade ores.
In this work, the spectrophotometric studies on the kinetics of redox reaction between gold(III) bromide complexes and sodium nitrite, were carried out. From the kinetic curves collected under different conditions of reactants concentration, addition of bromide ions, temperature, pH and ionic strength, corresponding rate constants have been determined. The obtained results suggest the complex path of the [AuBr4]– reduction consisting of two parallel, bimolecular reactions where different reductant species (HNO2 and NO2–) take place and consecutive step with the metallic gold production. The second-order rate constants at 20oC are equal to 2.948 and 0.191 M–1·s–1, respectively. The values of activation enthalpy and activation entropy for the first and the second parallel step of the reaction were found to be ΔH‡ = 29.18 kJ·mol–1 and ΔS‡ = –13.95 J·mol–1·K, and ΔH‡ = 40.75 kJ·mol–1 and ΔS‡ = –31.06 J·mol–1·K, respectively. It was found that the reaction accelerates significantly with the increase of pH and is inhibited with the increase of Br– concentration. The substitutive, inner-sphere mechanism of electron transfer in the studied system was also suggested.
The composite materials as FRP (Fiber Reinforced Polymers), which are characterized by benefits resulting from the combination of high strength reinforcement (as carbon, glass, steel or aramid fibers) with synthetic matrix are increasingly used to reinforce existing structures. Reinforcing System as FRCM (Fibre Reinforced Cementitious Matrix), which includes, among others, Ruredil X Mesh Gold System, is much less commonly used. However, the uniform and practical methods for calculating composite reinforced structures are not determined. Especially when considering the real conditions of structure exploitation, which requires further research in this field. In the paper the initial loading level influence on the efficiency of reinforced concrete beams strengthen using system Ruredil X Mesh Gold was investigated.
Thermo-optic properties enhancement of the bi-stable temperature threshold sensors based on a partially filled photonic crystal fiber was reported. Previously tested transducers filled with a selected group of pure n-alkanes had in most cases differences between switching ON and OFF states. Therefore, the modification of filling material by using additional crystallization centers in the form of gold nanoparticles was applied to minimize this undesirable effect. The evaluation of the thermodynamic properties of pentadecane and its mixtures with 14 nm spherical Au nanoparticles based on the differential scanning calorimetry measurements was presented. Optical properties analysis of sensors prepared with these mixtures has shown that they are bounded with refractive index changes of the filling material. Particular sensor switches ON before melting process begins and switches OFF before crystallization starts. Admixing next group of n-alkanes with these nanoparticles allows to design six sensors transducers which change ON and OFF states at the same temperature. Thus, the transducers with a wider temperature range for fiber-optic multi-threshold temperature sensor tests will be used.