선택한 단어 수는 입니다.
최소 단어 이상 선택하여야 합니다.
최소 단어 이상 선택하여야 합니다.
선택한 단어 수는 30입니다.
최대 10 단어까지만 선택 가능합니다.
최대 10 단어까지만 선택 가능합니다.
제안 방법
- To commence with, the baseline blast data and results were recorded by conducting two blasts on the said bench while it was worked in two separate slices (as described in section 2). The important baseline parameters and data are tabulated in Table 1. Thereafter, a series of blasts were conducted on the combined bench, 22-24 m high to meet the slated objectives. The salient blast parameters and data of these blasts are summarized in Table 2.
- Typically an image frame could capture 250-300 broken rock fragments. Analysis of almost 25-30 images for each muck pile was considered suitable for yielding a statistically representative sample for characterizing the fragmentation in one muck pile. These guidelines are per the recommendations published by various researchers (Reid, 1976; Maerz et al.
- Furthermore, the procurement of larger sized shovels, with greater digging reach was not an economically viable proposition. Giving due cognizance to these issues, the current research project was undertaken to with the objective of modifying the important blast design parameters for blasting the combined bench (22-24 m high) to augment the throw in a controlled manner, which in turn, ought to laterally spread the muck pile and drop it down for safe and convenient excavation of the muck pile by the specified rope shovel. The desired shape of the muck pile after controlled augmentation of throw and drop is illustrated in Fig.
- Such gigantic blasts are always endangered with ground vibrations, which called for a detailed study before attempting the blasts at field-scale. Accordingly, the predictor equations were established by conducting trial blasts.
- Needless to state that with the use of computers, the quantification process has become largely simplified, quick and almost inexpensive. The basis of this technique is to capture scaled images of the blasted muck pile using a high resolution camera in the field, and then to digitize and measure the delineated fragments to provide a measure of the particle size distribution.
- Blast casting is an established technique to move a substantial percentage (40-80%) of the overburden rocks to the disposal site inside the pit using the explosives. The technique aims at controlled amplification of throw distances by using the explosive energy. On the other hand, in normal rock blasting operations the broken rock should be thrown only far enough to allow room for expansion of the broken rock.
- To measure the fragment size in post-blasted muck piles, image capturing, processing and analysis technique was deployed. The imaging technique has been in use in the field of blasting for last almost two and a half decades.
대상 데이터
- The stripping ratio was about 1:3 and annual coal production was almost 10 Mte. It consisted of eleven overburden benches and 3 coal seams. The mine belongs to the Singrauli coa3-coal seams separated by substantial overburden partings.
- The overburden bench, on which the blasting studies were conducted, was 22-24 m thick (occasionally 28 m at certain locations). It consisted of medium to coarse-grained sandstone with uniaxial compressive strength of 10-15 MPa, tensile strength of 1-2 MPa and shear strength of 1-5 MPa. The bench was fairly uniform and did not possess any significant geological anomaly.
- The mine, where the studies were conducted, is one of the largest and well-mechanized surface coal mines, in India, having large capacity HEMMs including 4 draglines. A major fault divided the mine into 2-working sections; east and west section.
이론/모형
- 5 m long, painted in brown color) was placed in the image frames for calibration. For the purpose of processing and analysis of captured images to characterize the fragment sizes in the blasted muck piles, commercial state-of-art image analysis software FragalystTM was used.
- The fixing up of burden value was done by engineering calculation as per Konya’s formula for estimation of burden (Konya, 1995) after taking into account the related rock parameters, geological properties and explosive factors.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.