Question: With reference to the strata data given in the sketch and Table 5.3, seam depth is 1670 ft (509 m), strata dip is negligible and

With reference to the strata data given in the sketch and Table 5.3, seam depth is 1670 ft (509 m), strata dip is negligible and entries are planned 24 ft (7.32 m) wide. Mining height from the sandstone floor is 12 ft (3.66 m).

1 Determine the immediate roof safety factor.

2 Determine bolting pressure needed to reduce sag of all roof layers to zero, assuming bolts are anchored in R3 and the sag of R3 is negligible.

3 Layout a bolting pattern based on dead weight load basis and specify bolt length, diameter, steel grade, spacing, and bolt safety factor using R3 as an anchor stratum.

4 What is the immediate roof safety factor after bolting according to dead weight load design?

5 Explain how gas pressure above the roof shale would affect calculation of the safety factor of R1 beforebolting.

Co (103) psi (MPa) E (106) psi (GPa) To (103) y (pcf)

Co (103) psi (MPa) E (106) psi (GPa) To (103) y (pcf) h-ft (m) Rock type psi (MPa) (kN/m3) 1.2 (8.3) 0.65 (4.5) 0.45 (3.1) 0.25 (1.7) 1.8 (12.4) 148 (23.4) 142 (22.5) 136 (21.5) 95 (15.0) 149 (23.6) 26.0 (7.9) 1.5 (0.46) 2.0 (0.61) 16.0 (4.88) 18.0 (5.49) 16.0 (I10) 12.5 (86.2) 7.5 (51.7) 3.0 (20.7) 18.0 (124) 4.3 (29.7) 0.25 1.7 (I1.7) 0.19 4.1 (28.3) 0.20 0.35 (2.4) 0.30 4.5 (31.0) 0.25 R3 R2 RI SI FI Surface (not to scale) R3 sandstone ..overburden R2 laminated sandstone RI shale SI coal Fl sandstone

Step by Step Solution

★★★★★

3.46 Rating (166 Votes )

There are 3 Steps involved in it

1 Expert Approved Answer

Step: 1 Unlock

Given R3 R2 R1 S1 7777 F1 24 Surface 4 2 Find 1 Immedia... View full answer

Question Has Been Solved by an Expert!

Get step-by-step solutions from verified subject matter experts

Step: 2 Unlock

Step: 3 Unlock

Document Format (1 attachment)

26-E-G-R (228).docx

120 KBs Word File

Students Have Also Explored These Related Geological Engineering Questions!

Several proposals have been presented to increase the extraction ratio in a room and pillar system to 50% from 33%. The pillars are long compared with width, so the problem is essentially...

With reference to the radiation leakage data given in Exercise 2.15: (a) Calculate the sample mean. (b) Which gives a better indication of the amount of radiation leakage, the sample mean or the...

With reference to the radiation leakage data given in Exercise 2.15, calculate: (a) The sample variance. (b) The sample standard deviation.

With reference to the strata data given in the sketch and Table 6.4, seam depth is 1,670 ft, strata dip is negligible, and entries are planned 24 ft wide. Mining height from the sandstone floor is 12...

A thin ?low? metallurgical coal seam 3 ft (1 m) thick is mined at a depth of 980 ft (300 m). The main entries are mined 4 ft into the R1 roof stratum to give sufficient clearance for track haulage....

A multilevel room and pillar metal mine is under consideration in flat strata striking N60E. Entries are planned on strike, crosscuts up, and down dip. Table 6.6 shows depths and material properties...

A room and pillar coal mine is contemplated at a depth of 533 m in strata striking due north and dipping 18? east. Entries are driven on strike, crosscuts up, and down dip. Mining height is 4.6 m...

A multilevel room and pillar metal mine is under consideration in flat strata striking N60E. Entries are planned on strike, crosscuts up, and down dip. Table 6.8 shows depths and material properties...

On November 1, Vacation Destinations borrows $1.55 million and issues a six-month, 8% note payable. Interest is payable at maturity. Record the issuance of the note and the appropriate adjusting...

You are the project manager for a new web-based online shopping system. Due to market competition, your management has directed you to go live with your systems one week earlier than originally...

What should be the decision criterion when using the NPV method to evaluate capital investments? Does the IRR method use the same criterion?

Kims Asphalt does driveway and parking lot resurfacing work for large commercial clients as well as small residential clients. An inventory of materials and equipment is on hand at all times so that...

6. With a practical example, describe why a decision tree may be necessary for comparing alternative business strategies.

a) What is the null hypothesis tested for the coefficient of Run Time in the regression of Exercise 3? b) What is the t-statistic corresponding to this test? c) Why is this t-statistic negative? d)...

For the movies regression, here is a histogram of the residuals. What does it tell us about these Assumptions and Conditions? a) Linearity condition b) Nearly Normal condition c) Equal Spread...

A middle manager at an entertainment company, upon seeing the analysis of Exercise 3, concludes that longer movies make less money. He argues that his company's films should all be cut by 30 minutes...

On January 1, Tesco Company spent a total of $4,384,000 to acquire control over Blondel Company. This price was based on paying $424,000 for 20 percent of Blondels preferred stock and $3,960,000 for...

1. Is there a difference between aggressive accounting and earnings management? Would the motivation for using the techniques described in this case influence whether they should be labeled as...

In very humid climates where there are numerous bodies of water, such as in Florida, it is unusual for temperatures to rise above about 35C (95F). In deserts, however, temperatures can rise far above...

Use Castiglianos theorem to verify the maximum deflection for the uniformly loaded beam of Appendix Table A97. Neglect shear.

Find the range of resistance for the following resistors: a) 1 k ohms with a tolerance of 5%. b) 470 ohms with a tolerance of 2%. c) 22 ohms with a tolerance of 10%.

Solve Prob. 417 using Castiglianos theorem. Hint: Write the moment equation using a position variable positive to the left starting at the right end of the beam.

1 2 . 1 2 LAB * : Warm up: Online shopping cart ( Part 1 ) ( 1 ) Build the ItemToPurchase class with the following specifications: Attributes ( 3 pts ) item _ name ( string ) item _ price ( float )...

Consider the following information about three stocks; If your portfolio is invested 40 percent each in A and B and 20 percent in C, what is the portfolio expected return? The variance? The standard...

The NuPress Valet Co. has an improved version of its hotel stand. The investment cost is expected to be $72 million and will return $13.5 million for 5 years in net cash flows. The ratio of debt to...