scholarly journals PRELIMINARY ASSESSMENT OF THE EFFECTS OF BLAST DESIGN FACTORS ON FRAGMENTATION AT LAFARGE KANTHAN LIMESTONE QUARRY, CHEMOR, PERAK

2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Shaib Abdulazeez Shehu ◽  
Mohd Hazizan Mohd Hashim ◽  
Nur Aliah Hazirah Awang Kechik
Keyword(s):  
Compressive Strength ◽  
Correlation Coefficient ◽  
Uniaxial Compressive Strength ◽  
Fragment Size ◽  
Design Parameters ◽  
Stiffness Ratio ◽  
Blast Design ◽  
Powder Factor ◽  
Controllable Factors ◽  
The Mean

The results of blasting affect every other downstream operation in quarrying and mining process. Factors influencing blast results can be classified as either controllable or non-controllable. If desired fragmentation is to be obtained, the controllable factors (blast geometry and explosive properties) must be sufficiently designed to match the non-controllable ones (geological factors and legislative constraints). This study investigates the influence of blast design parameters on rock fragmentation. Six different blast designs were studied and analyzed. Rock samples were obtained from each face to evaluate the uniaxial compressive strength (UCS). Images of muck pile were captured using suitable digital camera. The images were uploaded into the WipFrag software to analyze the fragmentation resulting from the blasting. The particle size distribution of each blast was obtained, and the mean fragment size correlated with the blast design parameters. The percentage cumulative passing for gyratory crusher with the feed size of 1500 mm ranges between 92.8 to 100%. The stiffness ratio, powder factor and uniaxial compressive strength have high correlation with mean fragment size. The stiffness ratio increases with mean fragment size with a correlation coefficient of 0.89. The mean fragment size becomes finer with increase in powder factor with a correlation coefficient of 0.76. Powder factor also has a high correlation with the uniaxial compressive strength of the rock. The higher the uniaxial compressive strength of rock, the higher the powder factor needed for a specified fragment size. In this study, spacing to burden ratio has a very weak correlation with the fragment size. All the studied blast events produced good fragmentation with a uniformity index varying from 2.097 to 2.525.

scholarly journals UNIAXIAL COMPRESSIVE STRENGTH, DRY UNIT WEIGHT AND FRACTURE PATTERNS OF ULTRABASIC ROCKS IN OTHRYS MOUNTAIN (CENTRAL GREECE): CORRELATIONS AND EVALUATION

2018 ◽  
Vol 40 (1) ◽  
pp. 264
Author(s):  
K. Diamantis ◽  
Th. Karamousalis ◽  
Vas. Antoniou ◽  
G. Migiros
Keyword(s):  
Compressive Strength ◽  
Correlation Coefficient ◽  
Uniaxial Compressive Strength ◽  
Structural Complexity ◽  
Unit Weight ◽  
Tectonic Deformation ◽  
Tectonic Structures ◽  
Central Greece ◽  
Dry Unit Weight ◽  
Exponential Equations

Ultrabasic rocks, taken from the Othrys mt. (Central Greece), are studied in this paper. The structural geology and tectonics of the study area are described. Uniaxial Compressive Strength (UCS) and dry unit weight (γ) values are calculated and fracture angles are measured. The results are statistically assessed and empirical relationships (exponential equations) between UCS and γ are presented for the ultrabasic roch, divided in Peridotites, Serpentinised Peridotites and Serpentinites. Due to the low correlation coefficient of the Serpentinised Peridotites, it was decided that the Serpentinised Peridotites and Serpentinites should be examined together. The correlation coefficient of the combined category is much better than the separate ones. Furthermore, this paper demonstrates that the majority of the ultrabasic rocks tested were breaking at one angle (φ°), which mainly fluctuated between 75° and 90°. The fracture angles correlate with previously recognised geological (mainly tectonic) structures. The observed deviations are due to pétrographie variety, structural complexity, preferred orientation of olivine and orthopyroxene and internal imprinted tectonic deformation.

scholarly journals Minimising Backbreak at the Dewan Cement Limestone Quarry Using an Artificial Neural Network

2017 ◽  
Vol 62 (4) ◽  
pp. 795-806
Author(s):  
Khan Muhammad ◽  
Akram Shah
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Field Tests ◽  
Ann Model ◽  
Limestone Quarry ◽  
Blast Design ◽  
Powder Factor ◽  
Controllable Factors ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

Abstract Backbreak, defined as excessive breakage behind the last row of blastholes in blasting operations at a quarry, causes destabilisation of rock slopes, improper fragmentation, minimises drilling efficiency. In this paper an artificial neural network (ANN) is applied to predict backbreak, using 12 input parameters representing various controllable factors, such as the characteristics of explosives and geometrical blast design, at the Dewan Cement limestone quarry in Hattar, Pakistan. This ANN was trained with several model architectures. The 12-2-1 ANN model was selected as the simplest model yielding the best result, with a reported correlation coefficient of 0.98 and 0.97 in the training and validation phases, respectively. Sensitivity analysis of the model suggested that backbreak can be reduced most effectively by reducing powder factor, blasthole inclination, and burden. Field tests were subsequently carried out in which these sensitive parameters were varied accordingly; as a result, backbreak was controlled and reduced from 8 m to less than a metre. The resulting reduction in powder factor (kg of explosives used per m3 of blasted material) also reduced blasting costs.

scholarly journals Weathering Influence on Properties of Siltstones from Istria, Croatia

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Martina Vivoda Prodan ◽  
Željko Arbanas
Keyword(s):  
Compressive Strength ◽  
Size Distribution ◽  
Uniaxial Compressive Strength ◽  
Fragment Size ◽  
Slope Instability ◽  
Engineering Properties ◽  
Rock Masses ◽  
Weak Rocks ◽  
Erosion Processes ◽  
Weathering Grades

Slaking and weathering of weak rocks result in slope instability. Siltstones from flysch rock masses are highly susceptible to weathering, which causes rapid changes in the geotechnical properties and durability. This study investigated siltstone samples of different weathering grades from flysch rock masses from the Istria Peninsula, Croatia, and determined the effects of weathering on their engineering properties. Laboratory testing of siltstone samples of different weathering grades was conducted to determine the specific gravity, grain size distribution, Atterberg limits, and uniaxial compressive strength. The standardized slake durability index is not sufficient to classify the durability of weak rock masses such as siltstones. Therefore, the durability of siltstone samples of different weathering grades was quantified from the fragment size distribution after each of five slaking cycles. The tested samples were classified based on the disintegration ratio, and the modified disintegration ratio was used to determine potential long-term degradation of the tested samples. The results indicated that weathering has a significant influence on the plasticity, uniaxial compressive strength, and durability characteristics and thus affects the landslides and erosion processes in siltstones in the flysch zone of the Istria Peninsula.

scholarly journals Determination of Uniaxial Compressive Strength of Limestone

2019 ◽  
Vol 22 (1) ◽  
pp. 123-140
Author(s):  
Doris Vračević ◽  
Sanja Dugonjić Jovančević ◽  
Josip Peranić ◽  
Marko Hodanić
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Laboratory Testing ◽  
Direct Determination ◽  
Point Load ◽  
Design Parameters ◽  
Engineering Practice ◽  
Uniaxial Compression Strength ◽  
Schmidt Rebound Hammer

The most used parameter in rock engineering practice is the Uniaxial Compressive Strength (UCS). It is often estimated on the field or trough Index-to-strength conversion factors proposed by various researchers for a specific rock type. The research presented in the paper involved field estimation of Uniaxial Compressive Strength using Schmidt rebound hammer and Point Load laboratory testing on limestone rock samples. The results of the estimated UCS were compared to the Uniaxial Compression Strength laboratory testing results on limestone specimens taken from the same location, in order to compare corresponding UCS of limestone rocks. These results can contribute to better estimation of the local design parameters, when direct determination of the UCS in the laboratory is not possible, rather than adopting the values from around the world case studies.

scholarly journals Safe Blast Design for Efficient and Sustainable Underwater Excavation: Art Meets Science!

2021 ◽  
Author(s):  
BALAMADESWARAN P ◽  
A.K. Mishra ◽  
E. Kumar ◽  
K. Manikanda Bharath
Keyword(s):  
Fragment Size ◽  
Blast Design ◽  
Drilling Parameters ◽  
Powder Factor ◽  
Proper Design ◽  
Aqueous Layer ◽  
High Level ◽  
Selection Of

Abstract Most of the dredging work associated with harbor, port, channel deepening, and other related operation requires underwater blasting due to the characteristics of material being dredged / moved. Underwater blasting is typically used to remove rocks for deepen harbours and channels, creating channels and levees, installing conduits, and other more specialised blasting operations that shall be completed below sea. Usually, such dredging work occurs in deep-water of varying between 16–20m in order to remove just few meters of rocks. Hence, this type of blasting activity needs high level of skill and familiarity than equivalent activities carried out above the surface of water because of aqueous layer over the its rock. Therefore, the factors such as selection of drilling parameters and drilling equipment, selection of appropriate explosives and accessories, usage of correct powder factor, determination of safe explosive charges per delay and selection of suitable personnel are studied carefully for accomplishing the successful underwater blasting operations. In addition to the above, the system shall also address the proper design for the underwater blasts to excavate the rock to the required depth keeping in view the permissible allowances of minimum and maximum depth and fragment size required. While adopting underwater blasts, adequate safety measures are also defined for safety of men, other vessels in the blasting zone and structures from blasting vibrations. Here, the authors broadly outline their approach with respect to underwater blasting using the existing blasting technology, with a case study.

Injuries to the Coronoid Process of the Ulna with Involvement of the Lesser Sigmoid Notch

2020 ◽  
Author(s):  
Valentin Rausch ◽  
Sina Neugebauer ◽  
Tim Leschinger ◽  
Lars Müller ◽  
Kilian Wegmann ◽  
...  
Keyword(s):  
Fragment Size ◽  
Coronoid Process ◽  
Annular Ligament ◽  
Concomitant Injuries ◽  
Proximal Ulna ◽  
Sigmoid Notch ◽  
Coronoid Fractures ◽  
The Mean ◽  
The Stability ◽  
Arthritic Changes

Abstract Introduction This study aimed to describe the involvement of the lesser sigmoid notch in fractures to the coronoid process. We hypothesized that injuries to the lateral aspect of the coronoid process regularly involve the annular ligament insertion at the anterior lesser sigmoid notch. Material and Methods Patients treated for a coronoid process fracture at our institution between 06/2011 and 07/2018 were included. We excluded patients < 18 years, patients with arthritic changes or previous operative treatment to the elbow, and patients with concomitant injuries to the proximal ulna. In patients with involvement of the lesser sigmoid notch, the coronoid height and fragment size (anteroposterior, mediolateral, and craniocaudal) were measured. Results Seventy-two patients (mean age: 47 years ± 17.6) could be included in the study. Twenty-one patients (29.2%) had a fracture involving the lateral sigmoid notch. The mean anteroposterior fragment length was 7 ± 1.6 mm. The fragment affected a mean of 43 ± 10.8% of the coronoid height. The mean mediolateral size of the fragment was 10 ± 5.0 mm, and the mean cranio-caudal size was 7 ± 2.7 mm. Conclusion Coronoid fractures regularly include the lesser sigmoid notch. These injuries possibly affect the anterior annular ligament insertion which is important for the stability of the proximal radioulnar joint and varus stability of the elbow.

THE EFFECT OF ALTERATION OF THYROXINE BINDING CAPACITY ON THE DIALYZABLE AND ABSOLUTE FRACTIONS OF TRIIODOTHYRONINE IN CIRCULATION

1973 ◽  
Vol 72 (2) ◽  
pp. 265-271 ◽  
Author(s):  
J. H. Dussault ◽  
D. A. Fisher ◽  
J. T. Nicoloff ◽  
V. V. Row ◽  
R. Volpe
Keyword(s):  
Correlation Coefficient ◽  
Inverse Relationship ◽  
Binding Capacity ◽  
Hormone Concentration ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
A Value ◽  
The Mean ◽  
Male Subjects ◽  
Female Subjects

ABSTRACT In order to determine the effect of alterations in binding capacity of thyroxine binding globulin (TBG) on triiodothyronine (T3) metabolism, studies were conducted in 10 patients with idiopathically low (7 subjects) or elevated (3 subjects) TBG levels and 10 subjects given norethandrolone (7 male subjects) or oestrogen (3 female subjects). Measurements of serum thyroxine (T4) concentration, maximal T4 binding capacity, serum T3 concentration and per cent dialyzable T3 were conducted. Serum T3 was measured both by chemical and radioimmunoassay methods. In patients with idiopathically low TBG, the mean serum T4 concentration was low (2.4 μg/100 ml), the mean serum T3 level low (55 ng/100 ml), the mean per cent dialyzable T3 increased (0.52%), and the calculated free T3 concentration normal (186 pg/100 ml). In patients with idiopathically high TBG levels the mean T4 concentration was high (10.3 μg/100 ml), the mean T3 level slightly elevated (127 ng/100 ml), the% dialyzable T3 low (0.10%) and the calculated free T3 concentration low normal (123 pg/100 ml). The correlation coefficient between the per cent dialyzable T3 and maximal TBG binding capacity in the 20 subjects was 0.68, a value significant at the P < 0.01 level. Thus, alterations in binding capacity of TBG seem to influence T3 and T4 metabolism similarly; the inverse relationship between the % of dialyzable hormone and total hormone concentration tends to keep the absolue levels of free hormones stable.

scholarly journals Experimental Analysis of the Mechanical Properties and Resistivity of Tectonic Coal Samples with Different Particle Sizes

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2303
Author(s):  
Congyu Zhong ◽  
Liwen Cao ◽  
Jishi Geng ◽  
Zhihao Jiang ◽  
Shuai Zhang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Coalbed Methane ◽  
Coal Sample ◽  
Fine Particles ◽  
Particle Sizes ◽  
Tectonic Coal

Because of its weak cementation and abundant pores and cracks, it is difficult to obtain suitable samples of tectonic coal to test its mechanical properties. Therefore, the research and development of coalbed methane drilling and mining technology are restricted. In this study, tectonic coal samples are remodeled with different particle sizes to test the mechanical parameters and loading resistivity. The research results show that the particle size and gradation of tectonic coal significantly impact its uniaxial compressive strength and elastic modulus and affect changes in resistivity. As the converted particle size increases, the uniaxial compressive strength and elastic modulus decrease first and then tend to remain unchanged. The strength of the single-particle gradation coal sample decreases from 0.867 to 0.433 MPa and the elastic modulus decreases from 59.28 to 41.63 MPa with increasing particle size. The change in resistivity of the coal sample increases with increasing particle size, and the degree of resistivity variation decreases during the coal sample failure stage. In composite-particle gradation, the proportion of fine particles in the tectonic coal sample increases from 33% to 80%. Its strength and elastic modulus increase from 0.996 to 1.31 MPa and 83.96 to 125.4 MPa, respectively, and the resistivity change degree decreases. The proportion of medium particles or coarse particles increases, and the sample strength, elastic modulus, and resistivity changes all decrease.

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