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
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. Find the expected number of dumpers in the system.
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 D1 and D2. The minimum completion time of the project in days is
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. Find the probability that the shovel is sitting idle.
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
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 waiting time of the dumper in the queue?
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 probability that there is a queue (more than one workman) at the service counter is,
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
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?
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
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, find the expected number of dumpers waiting to be load in the system.
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
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
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
