Grain size distribution of waste rock masses of Kuzbass coal strip mines

Grain size distribution as a structural characteristic of waste rock and bulk masses in the course of mining and construction works acquires quantitative values in the process of rock blasting and hauling of rock mass. Such physical-mechanical and structural-textural parameters of a rock mass, as the ultimate strength of rocks and rock mass, fracturing, diameter of the natural rock jointing, have a significant impact on the blasted rock mass grain size distribution. On the other hand, such characteristics as stability, permeability of waste rock masses largely depend on the lithology and grain size distribution of the loosened rocks composing waste rock dumps and their height distribution within a dump. The paper describes the findings of the study of the grain size distribution of waste rock masses of Kuzbass coal strip mines and the features of its spatial variations within the masses. The textures of the bulk masses and physical and technical properties of the stacked rocks were studied both at the Kuzbass waste rock sites and in laboratory conditions. The grain size distribution of the fine lump part of the dumps with the lump size up to 50 mm was investigated by sieve method according to GOST 12536–2014, and the medium and large lump part was studied using oblique photoplanimetry. The field observations showed that the bottom part of the rock dumps, dumped by peripheral bulldozer or excavator methods was composed of coarse fraction with average lump size of: d_cr = 0.8–1 m, while the middle part, of rock lumps of d_cr = 0.4–0.6 m, and the upper part, mainly of fine fraction with lump size of less than 0.1 m. The ratio of length, width, and thickness of the blasted rock lumps was 1:0.85:0.8, which corresponds to elongated-flattened shape of the lumps. This requires significant number of coordinates for describing the lump positions in the rock mass, as well as taking into account the moments of inertia when modeling the motion of such lumps until they reach a stable position. Up-to-date non-commercial or commercial software and corresponding hardware can be used to take into account non-isometric shape of the lumps when modeling their motion.

Justification of parameters and technology of drilling and blasting operations to ensure the required lumpiness

The practice of mining and blasting operations both during the development of a mineral deposits, and at the mine design stage, often involves the question of selecting the technology options and operation parameters. Virtually all recommendations for selecting the best production option are based on minimizing the total costs for the entire technological cycle of mining activities. In most cases the optimal technology and parameters of mining and blasting operations depend on the commercial, maximum permissible and average size of the blasted rock mass, which are determined by the type and capacity of the mining haulage equipment. Therefore, the total costs will mainly depend on the commercial or average lump size and the cost of mining transport equipment. The article presents a methodology to select the best technological option for the drilling and blasting operations to obtain the optimal lumpiness (particle-size distribution) of the blasted rock. The optimal range of lumpiness is defined by the total minimum costs for the entire production cycle of mining and processing of minerals. In order to select a rational technology of drilling and blasting and to calculate their parameters it is proposed to take into account the integral criteria of lumpiness in addition to the average lump size. For this purpose, we studied the particle size distribution in the rock mass and in the muck piles.

Role of centchroman versus danazol in treatment of benign breast disorders

Background: The breast is a dynamic structure that undergoes cyclical changes throughout the menstrual cycle. Any aberration from normal physiological changes in breast produces different problem in breast. Many drugs are used for treatment for these disorders like Danazol, Bromocriptine, Tamoxifen and LH-RH analogue but still no consensus for any drug is present.Methods: The aim of our study was to analyze the effectiveness of drug Centchroman and its comparison with Danazol in treatment of benign breast disorders in respect to symptoms relief, decrease in nodularity and lump size, recurrence, cost and side effects of drug. This prospective study was conducted on 250 patients of benign breast disorders attending surgical OPD between May 2018 to September 2019 in SMS medical college and Hospital, Jaipur.Results: Tolerance and improvements in symptoms in centchroman group was more than danazol (100% vs 92.8%) with less recurrence in former group. While side effects varied between the two groups with menstrual irregularities more common in centchroman group.Conclusions: The study shows that centchroman is safe, more effective and less expensive to Danazol for the treatment of benign breast disorders in long term.

Neural coding of passive lump detection in compliant artificial tissue

Here, we investigate the neural mechanisms of detecting lumps embedded in artificial compliant tissues. We performed a combined psychophysical study of humans performing a passive lump detection task with a neurophysiological study in nonhuman primates ( Macaca mulatta) where we recorded the responses of peripheral mechanoreceptive afferents to lumps embedded at various depths in intermediates (rubbers) of varying compliance. The psychophysical results reveal that human lump detection is greatly degraded by both lump depth and decreased compliance of the intermediate. The neurophysiology results reveal that only the slowly adapting type 1 (SA1) afferents provide a clear spatial representation of lumps at all depths and that the representation is affected by lump size, depth, and compliance of the intermediate. The rapidly adapting afferents are considerably less sensitive to the lump. We defined eight neural response measures that we hypothesized could explain the psychophysical behavior, including peak firing rate, spatial spread of neural activity, and additional parameters derived from these measures. We find that peak firing rate encodes the depth of the lump, and the neural spatial spread of the SA1 response encodes for lump size but not lump shape. We also find that the perception of lump size may be affected by the compliance of the intermediate. The results show that lump detection is based on a spatial population code of the SA1 afferents, which is distorted by the depth of the lump and compliance of the tissue.

TRIPLE ASSESSMENT

Objectives: To determine the efficacy of triple assessment in diagnosis of malignant breast lumps in female patients taking corebiopsy as a gold standard. Setting: Breast Clinic, Unit-III, Department of Surgery, Nishtar Hospital, Multan. Period: October 2007 to March2008. Material & Methods: A total 0f 100 patients of breast lump, above the age of 14 years, having palpable lump of any size in breast wereselected according to inclusion criteria. Results: Out of 100 patients included in the study most of the patients were in the age group 45-54years i.e. 46 (46%) followed by 32 (32%) in the age group 35-44 years. According to occupation 67 (67%) were house wives, 13 (13%) wereteachers and 5 (5%) were nurses. In 48 (48%) patients the lump size was 2 cm, 35 (35%) patients had lump size from, 2-4 cm while in 17 (17%)patients lump size was > 4 cm. Presenting symptoms like lump was present in 50 (50%) patients, pain alone 25(25%) patients, discharge in 20(20%) patients and discharge with pain in 5 (5%). Lymph node status like grade-0 was seen in 60 (60%) patients, grade-1 in 21 (21%) patients,grade-2 in 15 (15%) patients and grade-3 in 4 (4%) patients. Conclusions: Triple assessment is a valuable tool for an accurate non surgicaldiagnosis of breast lump, allows assessment of breast cancer patient for conservative and neo-adjuvant primary treatment before surgicaltreatment.