PREPARED BY:MOUSOM SINGHA

B.E MINING ENGINEERINGIIEST SHIBPUR

MAY, 2016

Study of Dumper Cycle Time

Katamati Iron Ore Mine

Objective and Targets

Objective: To optimize dumper cycle time

Targets: To observe and collect data sample To analyse current level of dumper efficiency To identify means for improving cycle time

Dumper – Shovel Mining System

Costs 50 – 60% of the total mining costs

Standard Time Definition

Factors affecting Dumper efficiency

Truck-shovel match and allocation;

Shift operating schedules;

Haul road design and ramp gradients ;

Haul road rolling resistance ;

Cycle Time.

Cycle Time Study

The following factors were considered for the study: Waiting at the face Positioning Loading Travel(loaded); from face to dump Waiting at the dump Unloading Travel(empty); from dump to face Waiting at weigh bridge Weighing time

Cycle Time Study

The following data were also collected, though not directly related to dumper cycle: Weight of load in dumper Maximum and minimum speeds of dumpers

Cycle Time Study

It has been observed that two different kinds of ore based on their composition were mined simultaneously at the Katamati mine.

The two different ores were dumped at two different dump sites, namely, the Wet plant facility and the DCMP dump.

Hence, the cycle time study has been conducted separately for the two different dump sites.

For Wet Plant Dump

Average total waiting time: 4.13 minutes

Average positioning time: 1 minute

Average loading time: 5.07 minutes

Travel time (loaded): 8.92 minutes

Travel time(empty): 9.35 minutes

For Wet Plant Dump

Average weighing time: 1.50 minutes

Average unloading time: 1.78 minute

Average observed cycle time: 32.35 minutes

For Wet Plant Dump

Time Breakdown

Waiting at faceWaiting at dumpWaiting at wt. bridgeWeighingPositioningTravel(empty)Travel(loaded)LoadingUnloading

For DCMP Dump

Average total waiting time: 7.35 minutes

Average positioning time: 1 minute

Average loading time: 3.5 minutes

Travel time (loaded): 9.64 minutes

Travel time(empty): 8.85 minutes

For DCMP Dump

Average weighing time: 1 minute

Average unloading time: 0.78 minute

Average observed cycle time: 32.42 minutes

For DCMP Dump

Time Breakdown

Waiting at faceWaiting at dumpWaiting at wt. bridgeWeighingPositioningTravel(empty)Travel(loaded)LoadingUnloading

Other Data

Average travel time from OK line to face at start of shift: 6 minutes

Average lead distance: 5 km

Average weighted maximum speed: 36.21 km/hr

Average load carried: 95.72 T

Average number of swings of shovel: 9

Analysis

It is observable that the cycle time for both the dumps are almost identical; this can be owed to the fact that the distance covered by the dumpers are almost same – an average lead distance of 5kms from face to either of the plants.

Waiting time exceptionally long at DCMP; an average of 6 minutes

The number of operators is the same as that of dumpers; hence an absence of operators translates to a dumper being idle for the whole shift

Analysis

In one shift, shovel servicing was not completed during the preceding 1 hour of break time and 3 dumpers had to wait in queue for 10 minutes for the servicing

Even though the maximum speed allowed is 30 km/hr, the rule is often broken. This behaviour is more pronounced as the shift progresses. This can be attributed to fatigue of operators and consequent disregard of rules.

Analysis

In some cases, there is a dilemma of safety versus pressure of production. In a certain case, a dumper overtook a water-sprinkling truck even though over-taking is banned on the haul roads.

The DCMP breaks down often. In some cases, dumpers wait for a few minutes before they are finally instructed to dump near the DCMP and move along. This wait time can be reduced if DCMP informs the dumpers on time.

Recommendations

More operators should be employed in a shift, even as standby. Often, an absence of a single operator leads to a dumper being idle for the whole shift further resulting loss in production.

Starting time for shifts should be aimed towards a staggered format. This means that shifts for different operators should start at different times so that “bunching” effect is avoided whereby a total of about 1 hour of idle time is experienced at the start and end of the shift. Similarly time is lost during the break time.

Recommendations

Swarm-based truck-shovel dispatch system¹ or efficient Fleet Management Systems(FMS) like TALPAC, CAT FPC etc. should be installed.

¹Bissiri Y., Dunbar S., Hall A., Swarm –Based Truck-Shovel Dispatching System in Open Pit Mine Operations, Department of Mining and Mineral Process Engineering, University of British Columbia, Vancouver, Canada

Recommendations

Both side loading should be aimed. A sample schematic is given for example in the following slides:

Recommendations

All dumpers should be fitted with equipment checking the speed to prevent going above 30 km/hr, instead of only 1 dumper as is the case presently. However, since all observed dumpers cross this limit, further safety studies should be carried out to consider the possibility of raising this limit marginally, if regulations permit.

Thank you