Mine System Engineering — Part 1 MCQs with Explanations

9 is the correct answer to “Workmen arrive at a mine workshop to receive tools for maintenance. The inter-arrival time of workmen at the service counter is exponentially distributed with an average time of 10 min. The service time at the counter is also distributed exponentially with a mean time of 6 min. The average time spent by a workman waiting for his turn to be served in min is”. This question is standard in competitive examination syllabi for Mine System Engineering.

18 is the correct answer to “A mining project is composed of five activities whose three time estimates in months are given below: Activity Estimated duration (months) Optimistic time Most likely time Permissible time 1 - 2 1 1 7 1 - 3 2 5 8 2 - 4 1 1 7 3 - 4 2 5 14 4 - 5 3 6 15 The expected duration of the mining project in months is”. This question is standard in competitive examination syllabi for Mine System Engineering.

0.165 is the correct answer to “The failure data analysis of a longwall mining system consisting of thre major subsystems revealed that the failure rate of shearer, face conveyor any stage loader are 0.15/ hour, 0.2/ hour and 0.1/ hour respectively. If all the subsystems must be running for a satisfactory system operation, the reliability of the longwall system for a period of 4 hours is”. This question is standard in competitive examination syllabi for Mine System Engineering.

Infeasible solution is the correct answer to “Consider the following linear programming problem: Maximize z = 3x + 2y s.t. 3x + 2y ≥ 15 2x + 3y ≤ 6 x ≥ 0, y ≥ 0 The above linear programming problem has”. This question is standard in competitive examination syllabi for Mine System Engineering.

40 is the correct answer to “The variance of failure time (time to failure) of an electric motor in shovel is 1600 hr 2 . If the failure time follows an exponential distribution. the expected mean time between failure in hr is”. This question is standard in competitive examination syllabi for Mine System Engineering.

1310 is the correct answer to “The unit cost of transportation of a balanced transportation problem is shown below: Destination → D1 D2 D3 Supply Source s S1 7 3 6 60 S2 5 4 9 60 S3 8 6 7 80 Demand 50 120 30 The transportation cost of the initial basic feasible solution obtained by the North-West corner rule is”. This question is standard in competitive examination syllabi for Mine System Engineering.

220 is the correct answer to “A workshop has four machines for assigning four jobs. Each job can be assigned to only one machine. Estimated processing cost (in Rs.) at each machine to complete each task is given in the table below Machine M1 M2 M3 M4 Tasks T1 61 92 52 72 T2 42 49 69 85 T3 47 59 80 71 T4 65 70 68 72 The minimum value of total processing cost based on an optimal assignment schedules is”. This question is standard in competitive examination syllabi for Mine System Engineering.

Beta is the correct answer to “The probabilistic nature of activity times in PERT network is described by which one of the following distributions”. This question is standard in competitive examination syllabi for Mine System Engineering.

0.93 is the correct answer to “A pumping station in a mine has 4 pumps, P 1 , P 2 , P 3 and P 4 which are connected functionally in parallel configuration as shown in the figure. The individual reliability of the pumps P 1 , P 2 , P 3 and P 4 are 0.80, 0.90, 0.85 and 0.95 respectively. For an effective dewatering operation in the mine denoting system success, at least three pumps should be in operation. The reliability of the system is”. This question is standard in competitive examination syllabi for Mine System Engineering.

4.5 is the correct answer to “In an opencast mine, dumpers arrive at a shovel location with an average arrival rate of 12 per/hour. The inter-arrival times of the dumpers follow an exponential distribution. The service times of the shovel also follow an exponential distribution with an average of 3 minute. The average waiting time of a dumper in the queue in minutes is”. This question is standard in competitive examination syllabi for Mine System Engineering.

4 is the correct answer to “The feasibility region of an LP problem in variable x and y is given by the following constraints, in addition to the non- negativity constraints. y ≤ 60; x ≤ 90; x + y ≤ 70 The numbers of corner point feasible solutions for this problem are”. This question is standard in competitive examination syllabi for Mine System Engineering.

4000 is the correct answer to “A project network comprises five activities as shown below. The activity durations. in days. are as indicated. Crashing of any activity costs Rs. 1000 per day. If the project is crashed to the shortest possible duration without changing the critical path the total crashing coso in Rs. is”. This question is standard in competitive examination syllabi for Mine System Engineering.

40% is the correct answer to “The failure and the repair rates of a shovel are 0.06 hr-1 and 0.04 hr-1 respectively. The availability of the shovel in percentage is”. This question is standard in competitive examination syllabi for Mine System Engineering.

9 is the correct answer to “In a PERT network, the activities on the critical path are a, b and c. The standard deviations of the durations of these activities are 2, 2 and 1 respectively. The variance of the project duration is”. This question is standard in competitive examination syllabi for Mine System Engineering.

6 is the correct answer to “A mining machinery company has four plants at locations A, B, C, and D and three warehouses at destinations X, Y and Z. The number of machine units available at the plants A, B, C and Dare 5, 8, 7 and 14 respectively. The demands at X, Y and Z are 7, 9 and 18 respectively. The unit costs of transportation in rupees as follows: Destinations X Y Z Locations A 20 70 40 B 30 30 10 C 50 40 70 D 10 60 20 The total number of basic variables obtained based on the initial basic feasible solution is”. This question is standard in competitive examination syllabi for Mine System Engineering.

(0, 0, 0) is the correct answer to “The solution of the following system of linear equations is x + 4y + 3z = 0 3x + 5y + 2z = 0 8x + 10y + 12z = 0”. This question is standard in competitive examination syllabi for Mine System Engineering.

Beta distribution is the correct answer to “In PERT network, the activity duration is assumed to follow”. This question is standard in competitive examination syllabi for Mine System Engineering.

30 min is the correct answer to “In an opencast mine loading and transporting has been carried out by shovel dumper combination. There is only one shovel is in operation. Dumpers arrive at the rate of 10 dumpers per hour and it takes shovel on an average 5 minutes to load a dumper. Assume arrival is Poisson and service time is exponentially distributed. What is expected idle time of a dumper in the system”. This question is standard in competitive examination syllabi for Mine System Engineering.

10 is the correct answer to “A queue of trucks at a crusher plant hopper is known to be M/M/1 queue. The probability that there is no truck to unload is 0.3. Due to rains the mean service time at the hopper is increased by 30%. As a consequence, the expected number of trucks in the queuing system (including the one possibly unloading) becomes”. This question is standard in competitive examination syllabi for Mine System Engineering.

85 is the correct answer to “The time study data of an equipment deployed in a mine during a calendar month is given below. Total working hours = 400 Total maintenance hours = 100 Total hours of actual work = 240 The percentage of utilization of the equipment is”. This question is standard in competitive examination syllabi for Mine System Engineering.

Legal provisions is the correct answer to “ISO 9000 Quality Systems DO NOT contain”. This question is standard in competitive examination syllabi for Mine System Engineering.

68 is the correct answer to “The following project network is given with arrows as activities and the numbers by each arrow representing job durations in days. The network has two dummy activities D 1 and D 2 . The minimum completion time of the project in days is”. This question is standard in competitive examination syllabi for Mine System Engineering.

Total demand is equal to total supply is the correct answer to “A balanced transportation problem is characterised by”. This question is standard in competitive examination syllabi for Mine System Engineering.

20400 is the correct answer to “The feasible region of an LP problem is shown as given below. The maximum value of the objective function Z = 1600X 1 + 1200X 2 is”. This question is standard in competitive examination syllabi for Mine System Engineering.

15 is the correct answer to “There are 50 lemon trees in a reclaimed mine area. Each tree produces 800 lemons per year. For each additional tree planted in this area, considering all trees, the output number of fruits per tree drops by 10 lemons in a year. The number of trees that to be added to the existing reclaimed area in order to maximise the total number of lemons in the year is”. This question is standard in competitive examination syllabi for Mine System Engineering.

Work measurement is the correct answer to “In industrial work study, work sampling is a technique of”. This question is standard in competitive examination syllabi for Mine System Engineering.

1300 is the correct answer to “A mining project comprising of A, B and C activities is scheduled for 90 days at a cost of Rs. 1200 million. The manager of the project decides to reduce the time for completion of the project to 85 days. The decision was taken after 45 days, The minimum cost of the project in million rupees after crashing 5 days is”. This question is standard in competitive examination syllabi for Mine System Engineering.

Integer programming problem is the correct answer to “Which one of the following operation research problems is solved by the Branch and Bound algorithm”. This question is standard in competitive examination syllabi for Mine System Engineering.

C, 1 is the correct answer to “In the project network shown activity durations are given in months. If the activity can be crashed to expedite the project, which one would you crash and by how many months”. This question is standard in competitive examination syllabi for Mine System Engineering.

0.78 is the correct answer to “The failure data of equipment follows an exponential distribution. If the mean time between failure is 3000 hours. the reliability of the equipment for 750 hours is”. This question is standard in competitive examination syllabi for Mine System Engineering.

3.71 is the correct answer to “Four mines A, B, C and D are located along a road as shown with production in Mt per year 1, 2, 1 and 3 respectively. In order to handle total coal produced. the ideal distance of a coal washery along the road from the mine A in Km is”. This question is standard in competitive examination syllabi for Mine System Engineering.

0.91 is the correct answer to “A system of two identical mine pumps were to connected in series has reliability 0.49. If the pumps were to be connected in parallel. the system reliability would be”. This question is standard in competitive examination syllabi for Mine System Engineering.

$$\frac{{\left( {a + 4m + b} \right)}}{6}$$ is the correct answer to “In PERT analysis, the expected time to complete an activity is computed from the three time estimates : a most likely time (m), an optimistic time (a), and pessimistic time (b) using the expression”. This question is standard in competitive examination syllabi for Mine System Engineering.

A balanced transportation problem is the correct answer to “A company has three mines at locations A, B and C, which supply coal to power plants at D, E, F and G. Mines A, B and C produce 1800 t/day, 1700 t/day, and 2900 t/day respectively. Daily raw coal requirements at the power plants D, E, F and G from these mines are 2050 t, 1600 t, 1300 t, and 1450 t respectively. Unit transportation costs are as follows: Mines ↓ Power Plants D E F G A 3.5 4.0 2.5 5.5 B 4.5 3.7 6.0 4.7 C 4.2 3.8 5.2 2.9 The company has to minimize the total cost of transportation to the power plants. The problem is”. This question is standard in competitive examination syllabi for Mine System Engineering.

Beta is the correct answer to “The three time estimates of PERT network are assumed to follow”. This question is standard in competitive examination syllabi for Mine System Engineering.

0.999 is the correct answer to “A system consists of four elements A, B, C and D which are connectec functionally in a parallel configuration. The individual reliability of the elements is 0.80, 0.82, 0.85 and 0.90 respectively. The reliability of the system is”. This question is standard in competitive examination syllabi for Mine System Engineering.

0.891 is the correct answer to “A bunker-conveyor system as shown in the figure works under the following scheme: i. Bunker and two conveyors running ii. Bunker and either of the two conveyors running If the bunker and the two conveyors have identical reliability of 0.9. the system reliability is”. This question is standard in competitive examination syllabi for Mine System Engineering.

Optimal point lies in anyone of the interior points of the feasible region is the correct answer to “For an LP problem, identify the incorrect statement”. This question is standard in competitive examination syllabi for Mine System Engineering.

31400 is the correct answer to “A mining company has three mines (MI, M2 and M3) that supply coal to three power plants (P1, P2 and P3). The three mines produce 900. 1000 and 1200 te of coal per day respectively. The power plant requirements from these three mines are 1200. 1000 and 900 te per day respectively. The unit cost of transporting coal from the three mines to the three power plants in Rs. is given below Power Plants P1 P2 P3 Mines M1 8 10 12 M2 12 13 12 M3 14 10 11 Based on the initial basic feasible solution, using Vogel's approximation method, the total transportation cost in Rs. is”. This question is standard in competitive examination syllabi for Mine System Engineering.

0.899 is the correct answer to “In an opencast mine with shovel-dumper combination have 1 shovel and 6 dumpers. The reliability of the shovel is 0.9 and all the dumpers have equal reliability of 0.8. What is the system reliability”. This question is standard in competitive examination syllabi for Mine System Engineering.