The unadjusted RMR of a tunnel roof is 64. A single joint set exists in the roof as shown in the figure.
Using the abridged RMR table for adjustment orientation, the RMR is _______ (in integer)
The unadjusted RMR of a tunnel roof is 64. A single joint set exists in the roof as shown in the figure.
Using the abridged RMR table for adjustment orientation, the RMR is _______ (in integer)
Show Hint
Correct Answer: 54
Solution and Explanation
The given values are:
The unadjusted RMR of the tunnel roof is \( 64 \).
The dip of the joint is \( 40^\circ \), which falls within the range of \( 20^\circ \) to \( 45^\circ \).
The tunnel is driven in the direction with respect to the joint.
Step 1: Identifying the adjustment for joint dip.
According to the RMR adjustment table:
For a joint dip between \( 20^\circ \) and \( 45^\circ \), the adjustment rating is \( -2 \) when the tunnel is driven with the dip.
Step 2: Adjustment for the orientation of the tunnel.
The tunnel is driven in the same direction as the joint dip, meaning the adjustment rating is \( -2 \).
Step 3: Calculate the final RMR. To calculate the final RMR, we subtract the adjustment from the unadjusted RMR: \[ {Final RMR} = 64 - 2 - 8 = 54 \] Conclusion: The adjusted RMR of the tunnel roof is \( \mathbf{54} \).
Top GATE MN Mine Planning Questions
- The spherical semivariogram model (γ(h)) is represented by the following expression, where h is the lag distance.
\(y(h) = \begin{cases} C_0,\\ C_0+(C-C_0)[1.5\frac{h}{a}-0.5(\frac{h}{a})^3], &\\C, \end{cases}\)
The parameters Co, C and a are respectively known as - Match the following features with the corresponding symbols
Feature in mine plan Symbol P shaft 1 
Q staple shaft 2 
R Abandoned shaft 3 
S Abandoned staple shaft 4 
- The function of District Mineral Foundation established by state governments in India, is to
- A typical 24-hour activity of a mobile crusher plant is shown. The utilization, in %, of the plant, is (round off up to 2 decimals)
- The combined sound pressure level measured at a point in a production bench due to one dumper and one shovel is 95 dB(A). If the sound pressure level of shovel alone is 90 dB(A), the sound pressure level of the dumper alone, in dB(A), at the same point is_____.(round off up to 2 decimals)
Top GATE MN Mine planning and its components Questions
- The function of District Mineral Foundation established by state governments in India, is to
- A steeply dipping metalliferous ore body is non-susceptible to spontaneous heating. The blasted ore is used as the platform to work in a stope. Appropriate mining method for this orebody is
- The safety device used to arrest forward runaway tubs in rope haulage is
- The metal that belongs to Rare Earth Element category is
- In a depillaring face of an underground coal mine, both wet and dry bulb temperatures are 30 ℃. The relative humidity of the face environment, in percentage, is
Top GATE MN Questions
- Exposure to loud impulsive noise may lead to
- In a self-contained closed-circuit breathing apparatus,
- A rectangular mine airway of 2.0 m width and 2.5 m height has a bend with deflection of π/4 radian. If the radius of curvature of the bend is 4.0 m, the shock factor of the bend is (round off to three decimals)
- In an underground coal mine, two fatalities and three serious bodily injuries occurred during the year 2022. The average daily employment is 1100 and annual working days is 300. The severity index as per DGMS guideline for the mine is
- For a geared engine winding system, the man winding cage is placed at its normal position at pit top of the shaft. As per CMR 2017, the minimum space, in m, between the center of the hole of the detaching hook attached to the rope shackle and detaching belt plate is