Paste Pipeline Transportation of Pumping Backfill Technology with Long Distance and High Stowing Gradient in Cold and High-Altitude Areas

A paste pipeline transportation of pumping backfill technology with long distance and high stowing gradient is proposed to solve the problem of filling slurry transportation with low concentration, the filling body poor quality, and the transportation difficulties with long distance and high stowing gradient in Heiniudong copper mine (HCM). The physical and chemical properties of the backfill material, backfill proportion test, circular pipe experiment, and backfill system analysis evaluation were studied in the laboratory and outdoor, and the application in HCM was carried out to evaluate the technology. The research results show the feasibility of considering classified tailings and binder as backfill aggregates, and the optimum proportion of cement-binder-classified tailings applied in the stope and goaf is 1 : 4 : 8 and 1 : 4 : 15, respectively, with paste rheological properties of mass fractions of both being 74%∼76% and the backfill strength of about 1.5 MPa at 28 d. Furthermore, when backfill proportions and rate of flow are 1 : 4 : 8 and 50 m3/h, the pressure loss of the pipeline is around 0.4 MPa/100 m, and the backfill pump meets the backfill requirements. On this condition, the technology is capable of obvious economic benefits with the backfill cost of only 25.56 yuan/t, remnant ore recovery rate of 80%, and new output value of 1.28 billion. It creates a precedent for the paste pumping backfill technology with long distance and high stowing gradient in cold and high-altitude areas. The technology also provides reference mining experience for similar mines.

Identification of best fit crude oil of upper Assam basin for pipeline transportation

This paper attempts to identify a crude oil (CO) from eight different CO samples with a wide range of oAPI gravity from 13 to 43 belonging to Upper Assam Basin, India, to formulate the identified CO for pipeline transportation. Studies were conducted to understand the physical, rheological, and viscoelastic properties of the CO samples where physical properties included pour point (PP) and oAPI gravity, the rheological properties included viscosity (η), kinematic viscosity (K.V.), viscosity gravity constant (VGC), shear stress (τ) and shear strain (γʹ) and the viscoelastic properties were elastic modulus (G)' and viscous modulus (G''). This research aims at achieving PP < 9 °C for CO for the ease of flow through pipeline even during the extreme winter season in Assam when the ambient temperature drops below 10o C. SKO in 0%, 5%, 10%, and 15% was added with all CO samples to determine the physical, rheological and viscoelastic properties at 30 °C, since PP of most of the CO samples was near 30 °C. However, the important properties of SKO, i.e. smoke point, flash point and boiling point, were not addressed here as SKO was used for improving flowability through pipeline. Correlation coefficients (CC) were determined using CORREL function in Microsoft Excel to investigate the relationship between oAPI gravity and the other properties for all the CO samples to identify the best fit CO. CO3 and CO8 were identified from the relationships as the most desired CO samples and CO3 was obtained as the best fit CO for the pipeline transportation.

The Recent Progress China Has Made in the Backfill Mining Method, Part I: The Theory and Equipment of Backfill Pipeline Transportation

The backfill mining method is one of the common methods of mine mining worldwide, due to its capacity to maximize the recovery of mineral resources and protect the underground and the surface environment. Similar to the developing conditions of China’s mining industry, China’s backfill mining technology started late, and the level of its equipment is weak, but its development is particularly rapid. Especially after entering the 21st century, China has paid more attention to mining safety, environmental protection, and the continuous implementation of resources development, China’s backfill mining method has increasingly improved, and the level of filling equipment has gradually reached the most advanced level worldwide, which means China has been making great progress in the equipment of backfill mining method, and in recent years, China has also made great progress in the theory of backfill pipeline transportation. Therefore, Part I mainly focuses on both the theory and equipment of backfill pipeline transportation and the recent progress China has made in is introduced in two sections as follows: (1) the theory of backfill pipeline transportation and (2) the equipment of the backfill mining method. Finally, the authors claim that this paper serves just as a guide, tossing out a brick to get a jade gem, and we hope many more experts and scholars will be interested and engage in the research of this field.

Tandem Synthesis of Ultra-High Molecular Weight Drag Reducing Poly-α-Olefins for Low-Temperature Pipeline Transportation

Ultra-high molecular weight poly-α-olefins are widely used as drag reducing agents (DRAs) for pipeline transportation of oil and refined petroleum products. The synthesis of polyolefin DRAs is based on low-temperature Ziegler–Natta (ZN) polymerization of higher α-olefins. 1-Hexene based DRAs, the most effective at room temperature, typically lose DR activity at low temperatures. The use of 1-hexene copolymers with C8–C12 linear α-olefins appears to offer a solution to the problem of low-temperature drag reducing. The present work aims to develop two-stage synthesis of polyolefin DRAs that is based on selective oligomerization of ethylene in the presence of efficient chromium/aminodiphosphine catalysts (Cr-PNP), followed by polymerization of the olefin mixtures, formed at oligomerization stage, using efficient titanium–magnesium ZN catalyst. We have shown that oligomerization of ethylene in α-olefin reaction media proceeds faster than in saturated hydrocarbons, providing the formation of 1-hexene, 1-octene, and branched C10 and C12 olefins; the composition and the ratio of the reaction products depended on the nature of PNP ligand. Oligomerizates were used in ZN polymerization ‘as is’, without additional treatment. Due to branched character of C10+ hydrocarbons, formed during oligomerization of ethylene, resulting polyolefins demonstrate higher low-temperature DR efficiency at low polymer concentrations (~1 ppm) in comparison with benchmark polymers prepared from the mixtures of linear α-olefins and from pure 1-hexene. We assume that faster solubility and more efficient solvation of the polyolefins, prepared using ‘tandem’ ethylene-based process, represent an advantage of these type polymers over conventional poly(1-hexene) and linear α-olefin-based polymers when used as ‘winter’ DRAs.

IMPORTANCE OF PIPELINE TRANSPORTATION, USE OF CONCRETE WEIGHTING AND INSULATION MEASURES, USED DURING PIPELINE CONSTRUCTION

It was determined that the advantages and importance of pipeline transportation are related to the priority of environmental measures, the fact that costs are within the norm, and the possibility of uninterrupted transportation regardless of the season. Of the transportation methods, special attention was paid to pipe transportation, which is considered to be the most efficient. At the design stage of the pipeline, the organization of repair work during the operation of the pipeline and the capital investment allocated for construction are referred to the criteria of optimality. Although there are many technologies for pipeline aggravation, the most common of these is aggregation with a concrete coating layer. It is known that pipes with a diameter of 530 mm and a wall thickness of 14 mm are used during pipe laying in offshore areas. For concrete treatment of these pipes, it is recommended to use 400-500 grade slag portland or putty cement, especially in the marine environment. Waterproofing is considered suitable for protecting submarine pipes from wear. For the implementation of the waterproofing layer, it is recommended to use either brizol or insulation in construction. An important factor is the provision of special insulation measures in the open part of the pipe after welding, which is explained in the article. Welding must be performed in accordance with the standard and welding materials must be licensed. There are many technologies for welding. Manual arc welding has the widest field of application. Prior to welding, there are important works that can affect the quality of work, including heating the pipe and sawing the pipe ring. The differences between the post-heated welding process of the pipe and the unheated welding process are known from production experience. During operation, the pipeline is affected by climate change and loads (various shock effects; seismic; as well as ripples if submerged; underwater currents, etc.). If the weld is as strong as the base metal, it will continue to do so. This strength can also be achieved by the absence of temperature differences during welding. Keywords: pipe, pump, concrete coating, insulation, welding.