AMIE Study Circle

What are the causes and effects of stress concentration? Stress concentration is the localized increase in stress that occurs where a material's geometry changes abruptly—such as at holes, notches, fillets, grooves, or sharp corners.  Causes of Stress Concentration Stress concentration is almost always caused by a discontinuity or abrupt change in geometry that interrupts the smooth flow of stress.  Common causes include: Holes and Openings Sharp Corners and Notches Fillets with Small Radi Grooves and Keyways Threads Inclusions and Internal Defects Sudden Changes in Cross-Sectio Surface Roughness and Machining Marks Effects of Stress Concentration  The primary effect is that local stress can be many times higher than the nominal stress, which can lead to: Reduced Static Strength Fatigue Failure Crack Initiation and Propagation Reduced Load Capacity Brittle Fracture in Normally Ductile Materials Warping or Local Yielding What arc the advantages and disadvantages ...

The recent upgradation of the Indian Boiler Act in 2025 marks a pivotal moment for industrial safety in our country. Given the tragic loss of life in past incidents—most notably the devastating Vedanta boiler accident—this legislative update is a welcome and long-overdue step toward strengthening safety protocols. However, while the central government has taken a progressive step forward, we must address a growing crisis that threatens the very foundation of this reform: the systematic neglect of Boiler Operation Engineer (BOE) certification examinations by several state boiler boards. Join WhatsApp channel " BOE Adda " for latest updates  The State of Affairs: A Tale of Negligence Despite clear mandates under the Boiler Act requiring all states to conduct BOE exams regularly, we have observed a troubling pattern. States including Uttar Pradesh, Uttarakhand, Punjab, Tamil Nadu  and few others have repeatedly failed to conduct these essential examinations on ...

In mining, a safety helmet isn’t a permanent hat—it’s a timed shield. According to DGMS/CMR rules, PPE like footwear and helmets have a statutory shelf life, typically 3–5 years, because UV rays, sweat, and impacts degrade their polymers and shock-absorbing liners. After that date, a helmet that looks fine can shatter like glass under a falling rock. WhatsApp channel: Miners Adda   Yet, many companies treat these expiry dates as suggestions, not laws. They issue a new pair of steel-toed boots only when the old ones literally fall apart, and keep helmets on heads years past their certification. The savings? A few thousand rupees per worker. The cost? A fractured skull or a crushed foot that could have been prevented. In 2022, a drill operator in a Jharkhand mine took a minor blow from a loose rock. His helmet—six years old—cracked clean through, sending plastic shards into his scalp. He survived, but with permanent nerve damage. The company’s internal audit later revealed they’...

MCQ (i) An increase in steam pressure of a boiler during start-up from 4 bar (g) to 12 bar (g), will result in decrease of ____. (a) enthalpy of steam (b) sensible heat of steam (c) specific volume of steam* (d) saturation temperature of steam.

MCQ (i) Following part is not included in Boiler accessories ____. (a) ESP                                                             (b) Economiser (c) Chimney*                                                   (d) Air pre-heater

A wide variety of mining processing and materials-handling equipment is used in underground and surface mining, and in preparation/processing plants with many noise sources on them having a range of varying noise levels. Frequently, a single piece of equipment will combine several individual noise sources.

A steam table gives the properties of water (liquid, vapor, and mixture) at different temperatures and pressures. Common properties listed:   T = Temperature   P = Pressure (absolute, not gauge)   v = Specific volume (m³/kg)   u = Internal energy (kJ/kg)   h = Enthalpy (kJ/kg)   s = Entropy (kJ/kg·K)   x = Quality (mass fraction of vapour, 0 = sat liquid, 1 = sat vapour)

Explosive is a solid or liquid substance or a mixture of substances which on application of a suitable stimulus is converted in a very short time interval into other more stable substances, largely or entirely gaseous, with the development of heat and high pressure. 

This system is simple in construction and maintenance. It can suit any gradient and curvature of roadways. Even gravity can assist it to the extent that in hilly terrain it could be installed. This type of arrangement, when installed in an incline, it is known as self-acting-incline.

Mechanical conveyors are used for transporting most bulk solids (sand, ash, grains etc.) handling. They are used not only in transportation of bulk solids from one location to another location but also for feeding, discharging, metering and proportioning such materials to and from bulk solids storage silos and other solids handling and processing equipments. Conveyor is a device which is used for continuous transportation.

To extract mineral by underground methods of working, the access may be by an incline (a tunnel from surface to the mineral bed), by an adit, or by a well which is called shaft or pit in mining terminology.

Percussive Drilling It is the oldest method of drilling. In this method a great variety of bits suspended from cables or rods have been used to bore through different kinds of rock. Rope boring was widely used for oil well drilling in which they raised a heavy blunt chisel type of bit jumping on the end of a cable. This enabled a great speed in fairly hard rocks. This blunt type chisel bit is not suitable for clays and soft marls which not only cushion the blows but ball up the bit until it attains a sucking action that renders the bit almost useless. For soft mudstones and shales a long heavy and narrow tool proved successful.

In the rugged world of mining, the term " digital mine " gets thrown around like dust in a blast site. But what does it really mean? Is it a fully automated sci-fi operation, or a practical upgrade to traditional methods? Spoiler: It's the latter—and it's delivering real results today.

The major points in selection and design of a belt conveyor are: Checking/determining capacity of a conveyor. Calculating maximum belt tension required to convey the load and selection of belt. Selection of driving pulley. Determining motor power. Selection of idlers and its spacing.

Blasting in underground coal mines is a specialised operation. The proper use of explosives is vital to safety, influences the cost of production, and in many cases, has a direct bearing on the quality of the coal produced. The possible occurrence of highly inflammable mixtures of methane and air and exposable dusts has led to special statutory requirements for explosives and their use in such mines.

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.

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.

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.

The minimum amount of air which supplies the requisite amount of oxygen for complete combustion of fuel is called theoretical or stoichiometric air . The reaction is, however , not likely to proceed to completion if the fuel is supplied just with stoichiometric air. The objective of complete combustion is achieved by supplying excess air ; excess air means the amount of air supplied in excess to that theoretically needed to burn fuel completely. The quantity of excess air depends on the type of fuel and the method of combustion used and may vary from 25 to 100 percent. 

A tragic boiler explosion occurred on April 14, 2026, at Vedanta Limited's 1,200 MW coal-fired thermal power plant in Singhitarai village, Sakti district, Chhattisgarh. The incident resulted in approximately 20 fatalities and over 30 injuries, many from severe burns, among workers (including those from a subcontractor). Operations at the affected unit have been suspended, and authorities have filed an FIR against company officials, citing potential lapses.