[en] In mining low grade uranium deposit, in situ blasting and heap leaching is technically feasible with low cost. By many years practice demonstration, lumpiness of blasting and heap construction is one of main factors which influence of uranium leaching effect. How to under the specific environment and ensure safety condition, controlling lump size of in situ blasting which are used in heap leaching and improving the quality of the heap become extremely critical issue in situ blasting and heap leaching process. Based on the study and practice of blasting in railway construction and open-pit mining, in combination with the resource conditions and the actual situation of production in one Gannan uranium mine, application and exploration of deep hole blasting test and stratification of heap construction technology in stope was carried, the test results show that the bulk yield rate is greatly reduced, quality and heap leaching effect in stope are greatly improved too. (authors)

[en] Mining low grade uranium deposit by stope leaching method is technically feasible and low cost. The practice has proved that the stacking of blasting fragmentation is one of the main factors that directly affect leaching effect. Based on the specific environment and safety, clattering blasting heap size, improving the quality of the heap of stope leaching process become extremely critical issue.Based on the study and practice of blasting railway construction and open-pit mining, combined with a uranium mine in Gannan resource conditions and the actual situation of production, application and exploration test of deep hole blasting in of heap construction technology, the results show that the bulk yield can be greatly reduced, quality and heap stope leaching effect can be improved. (authors)

[en] Medium length holes shaft excavation by sectional blasting is an effective method to solve the difficulty of the feedstock in worked out section, to speed up the construction of filling shafts and to reduce the cost of tunneling. According to the theoretical analysis of shaft excavation by succeeded blasting in China, the method of parallel hollow hole is used as the free surface of cutting hole scheme. The height of filling shaft is 8 m, the sectional blasting is used, each sectional height is 4 m. The second differential delay detonators are used, the detonating sequence is that cutting hole is the first one, auxiliary hole is the second one, diagonal hole is the third one, and peripheral hole is the fourth one. All the filling holes are filled with continuous column charge. The total explosive payload is 203.40 kg, unit consumption is 11.19 kg/m³, and the unit cost is 264.08 RMB Yuan/m³. Shaft excavation by blasting has achieved good expectation. The method has achieved the goal of safe, efficient and economical shaft-completion. (authors)

[en] A shallow hole shrinkage mining stope leaching method was used to recover uranium in a uranium mine. The problems such as large blasting fragmentation and uneven distribution of drill lixiviant resulted in low leaching rate, long leaching cycle and low production efficiency during production. Aimed to problems and combined with the actual situation of the uranium mine, the shallow hole shrinkage mining method was improved, that is, according the results of geophysical logging, high grade ores and low grade ores were blasted and mined respectively, and the high grade ores were sent to the surface and treated by heap leaching process, and low grade ores were leached in stope. This improved method was called shrinkage mining method with respective blasting and mining. Compared with shallow hole shrinkage mining stope leaching method, the recovery rate of the improved method was increased by 17.2%, thereby maximizing the recovery of uranium resources. (authors)

[en] Highlights: • MoS₂-reduced graphene oxide aerogels have been firstly printed with a three-dimensional freeze printing method. • The hybrid structure consists of small MoS₂ patches attached on larger two-dimensional rGO flakes in a macroporous framework. • The hybrid aerogels are utilized for sodium ion battery anodes. -- Abstract: This study reports a 3D freeze-printing method that integrates inkjet printing and freeze casting to control both the microstructure and macroporosity via formation of ice microcrystals during printing. A viscous aqueous ink consisting of a molecular MoS₂ precursor (ammonium thiomolybdate) mixed with graphene oxide (GO) nanosheets is used in the printing process. Post-treatments by freeze-drying and reductive thermal annealing convert the printed intermediate mixture into a hybrid structure consisting of MoS₂ nanoparticles anchored on the surface of 2D rGO nanosheets in a macroporous framework, which is fully characterized with FESEM, TEM, XRD, Raman spectroscopy and TGA. The resulting hybrid MoS₂-rGO aerogels are studied as anodes for sodium ion batteries. They present a high initial specific capacity over 429 mAh/g at C/3.3 rate in the potential range of 2.5–0.10 V (vs Na⁺/Na). The process involves both reversible 2 Na⁺ insertion and slow irreversible conversion of MoS₂ to metallic Mo. At higher rates, the conversion reaction is suppressed and the electrode is dominated by fast Na⁺ intercalation with good stability. This demonstrates that the 3D printing technology can be used as a processing technique to control the materials properties for energy storage.