The use of underground ring drilling and blasting holes is common, given their compatibility with various mining methods and use in the construction of underground structures like the ore draw bells. ...Working conditions and rock properties can vary significantly, making it essential to monitor and analyze the blasting results. If necessary, the adjustments and optimizations should be made to the drilling and blasting patterns based on the properties of the used explosives. The aim of this paper is to develop a stopping mining method model using the blastholes, as well as a unique drilling and blasting pattern for excavation the initial slot in the Datamine Aegis. The objective was to compare several types of explosives with different properties in this context, predict the blast outcomes in terms of break radius, and highlight the significance of all explosive parameters in selecting and optimizing a drill and blast ring pattern.
The position of deposits and ore bodies for the underground mining in the underground mine Jama Bor, in relation to the terrain surface, old works of the Jama and Open Pit in Bor, and in relation to ...the mining infrastructure limits the selection of excavation methods with the applied technologies up to now. This paper presents the block method of excavation with backfilling the excavated space with the paste backfill of the Bor River deposit.
The dominant technology in hard rock mining is drilling and blasting; therefore, the importance of fragment size estimation is an essential problem in the mining industry. By using a theoretical ...foundation that explains rock-fracturing mechanisms by blasting, a 3D fragmentation model with general applicability was developed. The main capabilities of the model are the ability to consider different and complex blasting patterns, both with parallel and non-parallel boreholes, and different explosive and rock properties. The geological input of the model is defined by generating the primary blocks within rock mass using discrete fracture networks. The model handles different, complex geological setups and blasting scenarios that include bench, ring, and tunneling blasting. Also, it considers borehole deviation, misfires, and the influence of previous blasts. Full-scale ring blasts were carried out to validate the model against real-world data, and the results showed a high level of agreement between model predictions and in situ data. In situ data were collected using image processing methodology and WipFrag v4 software. X50 and X80 size values showed a maximum error in prediction of around 15%, while R2 values between fragmentation curves were approximately 90% without a detailed model calibration to the obtained data.
Pseudoperonospora cubensis is one of the most important cucumber diseases. Its continued appearance in most parts of Europe, Asia and the United States and its persistence represent a significant ...threat to the production of cucumbers around the world. Although the disease has been successfully suppressed for many years, severe epidemics have been reported since 2004, especially in the United States (Ivanović, M. et al. 2001). Whether this is the result of a change in the pathogen population or changes in the environment, it is currently unknown. The control of the Pseudoperonospora cubensis relies on the application of fungicide and the resistance of the host itself to the pathogen. Nonetheless, the resistance of Ps. Cubensis is recorded worldwide, and host resistance is no longer sufficient to control the disease as it once was possible. Additional costs on fungicides, along with the potential loss of yield and up to 100% caused by the Pseudoperonospora cubensis, endanger the long-term sustainability of cucumber production (Đurovka, 2001).
Knowledge of Ps. cubensis, its epidemiology, the process of infection and genetics of the population is currently lacking, which is why it is necessary to encourage future efforts for the development of resistant sorts as well as fungicides in order to successfully combat Pseudoperonospora cubensis (Ivanović, et al. 2007). Researching this pathogen can help us understand it, and develop effective measures for diagnosing and suppressing Ps. cubensis.
In addition to preventive measures in the protection of cucumbers against plant diseases, the efficiency of fungicides, which suppress Pseudoperonospora cubensis, is a limiting factor in cucumber production. Pesticides with the following active substances were used in the study: propineb, metalaxyl + mancozeb, metiram, dimethomorph + mancozeb, azoxystrobin, amethotradine + dimethomorph, azoxystrobin, fluazinam (Vojinović 2014, Vojinović 2015.). The efficiency of the tested fungicides was calculated according to Abbot's formula, and it is 92-97% (Table 1.).
WEED FLORA IN ALFAFLA CROPS Živić, Jelica; Vojinović, Milić; Stančić, Ivica ...
International Conference on Technics, Technologies and Education,
2019
ICTTE 2019
Journal Article
Alfalfa is a perennial crop that is grown several years on the same surface and because of this there are specificities in the composition and structure of the weed community. This leads to ...difficulties in suppresses and reduction of pests, diseases and weeds at the yield of alfalfa. The basic harmful effect of weeds is reflected through the competitiveness of water, nutrients and light. Weeds generally have low nutritional value, unpleasant smell and taste, and also affect the quality of alfalfa seeds. The most common types of economy effective perennial weed are Cirsium arvense (L), Sorghum halapense (L.), Convolvulus arvensis (L.) and Cuscuta genus. All agro-technical measures, which enable good soil, quality sowing, as well as plant protection later, are the basic measures for the protection of alfalfa from long-lasting weed species. This paper is based on analysis of weeds flora in alfalfa crops in the Nis district. The presence of the fifteen most important types of weed plants was found in all nine analyzed areas of alfalfa crops. Among the weeds, most common are Agropyrum repens(L.), Amaranthus retroflexus(L.), Chenopodium hybridum(L.), Cuscuta sp.(L.), Sorghum halapense(L.).
The damage from the present weeds in maize crop is shown by the reduction of yield in almost every year and their suppression is completely economically justified. The right selection of herbicides ...mostly depends on the presence of dominant weed species and the time of application. The paper presents the distribution and existence of economically harmful, invasive and quarantine weed species (Abutilon theophrasti, Agropyrum repens, Amaranthus retroflexus, Ambrosia artemisiifolia, Capsela bursa-pastoris, Chenopodium album, Chenopodium hybridum, Cirsium arvense, Convolvulus arvensis, Datura stramonium, Avena fatua, Calystegia sepium …) on ten locations of maize crops in the Nisava district. Estimation of the species presence was done in two shootings (May and August) on scale 1-4 (1 - species appears individually and occupy up to 5% of the surface, 2 - appears and occupies 5-25% of the surface, 3 - appears often and occupies 25-50% of the surface, 4 - the species prevails over the cultivated plant and occupies over 50% of the surface).
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