Представлены результаты экспериментов по влиянию энергии удара на интенсивность ударно-абразивного изнашивания модельного инструмента из трех марок инструментальных сталей вида конической пики при ударном взаимодействии с фрагментом гранита. Часть инструмента подвергалась типовой термической обработке, практикуемой на заводах-изготовителях пик, другая — дополнительной обработке холодом или криогенной обработке. Для обоснования возможности переноса экспериментальных данных на натурные условия устанавливались рабочие параметры эксперимента, при соблюдении которых его условия будут подобны условиям работы пики гидромолота. Для выполнения указанного подобия уровень контактных напряжений между модельным инструментом и породой в экспериментах был таким же, как и при ударном внедрении пики. Установлена зависимость между интенсивностью ударно-абразивного изнашивания и энергией удара модельного инструмента, на основании которой рассчитаны интенсивности изнашивания пики гидромолота JCB HM380 при разрушении гранитных фрагментов. Оценивалась наработка пики, за которую принималось количество нанесенных ей ударов до полного изнашивания острия. Из сравнения наработки пик, изготовленных из анализируемых сталей и подвергнутых указанным видам термической обработки, сделан вывод о целесообразности внедрения операций обработки холодом и криогенной обработки в технологический процесс изготовления пик гидромолотов.

The necessary condition for the operation of crushers in the production of crushed granite is feeding of the crushers with granite fragments of a certain size. At the same time, granite fragmentation after blasting does not always meet the required size for the crushers and needs additional destruction by blasting or disintegration directly on site. Hydraulic breakers are most often used in disintegration of oversizes. For example, in quarries in Vietnam, JCB HM380 hydraulic breakers with a fracture energy of up to 2.5 kJ are widely used. The working tools of the hydraulic breakers are steel picks of various diameters and shapes. The operation of this tool is accompanied by its intensive wear due to the impact-abrasive action of rocks; the pointed part of the tool gets gradually blunted, which affects the rate of penetration of the pick in rock. In this regard, it is relevant to determine the influence exerted by the degree of wear of the pick on the performance of the hydraulic breaker, and to find out whether replacement or re-sharpening of the pick is expedient. In this paper, based on the previously determined crack propagation velocity in granite and the impact time, the length of the fracture is calculated. The dimensions of a crack in a granite block are calculated depending on the degree of blunting of the pick at a certain number of blows per cycle. At the same time, the limiting value of a crack that causes chipping of a piece from rock mass was considered as the fracture length to free surface at different degrees of pick blunting. Based on these calculations, the average productivity and energy input of disintegration process were determined. It is shown that for a tool with a completely worn tip, the decrease in the productivity and the increase in the energy input of fracture reach two times compared with a sharpened pick. In this regard, from the point of view of increasing the hydraulic breaker capacity, it is advisable to replace or re-sharpen the pick after complete wear of its tip.

he purpose of the work is to analyze the aggregates of complexes for the extraction of marine minerals. In particular, the variants of complexes, their advantages and disadvantages are considered. The complex is analyzed, which uses robotic pickers/reclaimers of the walking type to perform mining operations of ferromanganese nodules (FMN) or cobalt-bearing manganese crusts (CMC). Results. The variants of complexes for mining of bottom deposits are analyzed, advantages and disadvantages of different variants are indicated. The device for collecting minerals on the bottom, developed in SPMU, is described, laboratory studies of the model of such a device are considered, the main parameters are presented, the dependence of productivity on the size and time of operations of the cycle of work is indicated. It is determined that for minimal impact on the seabed biota it is necessary to use walking submersibles with an actuator for extraction in the form of rarefaction chambers or a grapple with an impactor (depending on the type of solid minerals). It is shown that the productivity of the walking underwater vehicle varies with the diameter of the rarefaction chamber plates: the optimum plate diameter is 1.5 m. Experimental study of hydrodynamic resistance of “foot” models with different midships cross-section has been carried out. According to the experimental results, the conclusion about the preferred design of the “foot” was made: the cross-section should be a streamlined shape with the smallest drag coefficient cx and have a continuous surface without holes. Experimental studies of tine models movement in water have shown that it is reasonable to use as tine parts the structures without holes, streamlined ellipsoidal shape. Calculations of productivity of mining units when using rope hoisting from the bottom to the ship have shown the necessity of using four or more hoisting devices for realization of the required annual productivity of more than 1 million tons per year. The stages of creating a workable extraction unit including a vessel, vertical lifting device and a system of deep-water collectors require very significant material and monetary costs, so they should be carried out in accordance with the R&D plan and tasks of the relevant ministry and agency and require coordination of efforts of investors, scientists and machine builders.