AMIE Study Circle Blog

Each explosive has certain specific characteristics or properties. Some of the principal properties of explosives which influence the ultimate choice are: Detonation velocity; strength energy; detonation pressure; density; safety in handling; storage qualities; water resistance; sensitivity; sensitiveness; medical aspects; inflammability; resistance to freezing; permissibility. Detonation Velocity The detonation velocity is a measure, in meters per second or feet-per-second, of the speed at which the detonation wave travels through a column of explosives. Many factors affect the detonation velocity such as explosive type, diameter, confinement, temperature, and priming. Study Material for DGMS and Other Mining Engineering Exams By IITR Faculty Type   The detonation velocities of today's commercial explosives range from about 1500 m/s e.g. ANFO in small diameter holes and certain permissibles to more than 6700 m/s e.g. detonating cords and cast-primers. Every explosive has an ultima...

Shovels The field of application of power shovels (see figure) extends from the removal of shallow overburden prior to opencast mining, to stripping and mining deposits of large area and tonnages which are fairly uniform in character, and shovelling material broken down by explosives. Power shovel Crawler mounted face shovel is the machine most capable of handling hard, heavy, blasted ground by virtue of its positive crowd action and high break-out force. It can accurately spot for loading dump trucks, rail wagons, etc.. the larger units are used for direct casting. The shovels dig the material above the base level and have little ability to dig below base level. For the operation of the shovels a competent floor is required to allow positive traction by crawlers, without the possibility of damage or ‘bogging down‘ and the surface area of the crawler must provide a bearing pressure to match that can be accepted by the ground. The level width must be sufficient so as to preferably allow...

Any exploration program can be classified by successive stages - each stage is designed with a combined specific objective to achieve within the time schedule and allocated fund. The outputs of each stage provide inputs to the next successive stage. The stages for major and with limited application for minor minerals are placed in ascending order with respect to increase geological confidence in the context of any exploratory procedure. Reconnaissance "Reconnaissance" is the "grassroots" exploration tor identifying enhanced mineral potential or initial targets on a regional scale. The preparations at this stage include literature survey, acquisition of geophysical data, if any. synthesis of all available data and concepts, and obtaining permission from the State/Provincial/Territorial Government. The activities encompass remote sensing, airborne and ground geophysical survey, regional geological overview, map checking/ mapping on 1:250.000, 1:50.000 scales, geochemi...

To burn certain amount of fuel, some theoretical air is required. It is given by 4.35[(8/3 C + 8H 2 + S) – O 2 ] kg This is the theoretical air required. But, in practice, some more air or extra air is supplied to ensure complete combustion of the fuel. WhatsApp channel " BOE Adda "   If more air is supplied, then there will be a cooling effect and the efficiency will decrease. Also, if less air is supplied, then complete combustion will not take place. Combustible substances will escape from the stack. Again, there will be a loss in efficiency. So, it is required to adjust the air supply in such a way that complete combustion will take place without much extra or excess air. It is to be kept in mind that excess air and excess oxygen are not same. Air has roughly 21% oxygen by volume. So, 100% excess air is approximately equal to 10.5% oxygen remaining at the boiler exhaust stack. Excess air percentage = [oxygen % in flue gas/(21 - oxygen %)] x 100 Actual air quan...