Keeping Load Size In Range

When it comes to the amount of dirt put on the back of a mining truck, it is true that size does matter.

Or at least the size of the load.

If you make it too light you are leaving cash/revenue on the table.

If you load it too heavy then you run the risk fo slowing other trucks down and impacting on cycle times.

So what is the optimum payload to run in your trucks?

THE CHALLENGE

This site had adjusted their payload from 220 tonnes to 228 tonnes and were now looking to increase it again.

There was however a lot of apprehension about the change and what should be the target.

In addition to this the target had already been adjusted once but the actual average payload was still only 213 tonnes.

The site’s plan was built around a target of 220 tonnes.

Given that the actual payload was only 213 tonnes and the target had been set at 228 tonnes, is there any value in adjusting up again?

The site decided to use the MaxMine Load Unit operator tool to focus on meeting this target and pushing it closer to the target.

So the question remains why adjust a targets? If you aren’t achieving them, fix that first.

THE CHANGE

Over 8 months this site adjusted and achieved their targets from 220 tonnes up to 234 tonnes.

With assistance from the MaxMine team the site was able to assess a number of metrics and monitor the team outputs.

Identifying the Problem?

The challenge is actually really simple, put the optimum amount of dirt into the trucks without slowing them down, injuring operators or damaging the equipment.

There were a number of problems to identify and solve for.

  1. Why isn’t the target being achieved?
  2. What is the optimum payload for the site?
  3. How do they achieve it?

Given that MaxMine was already on site and being used for additional solutions, the data analysis was able to take place very quickly.

It was found that with the loading strategy and the number of passes that the site leadership had set as an expectation this was leading to the site target being missed 54% of the time.

There were a number of factors influencing this decision to restrict the number of passes, however diving into the data it was found that a large number of operators were choosing to increase the number of passes by 1 and in these instances they were 95% more likely to achieve the target payload.

It was established very quickly that the site was able to increase the number of passes to the optimum level.

This then led to the target being lifted to 228 and was being achieved.

The site then wanted to see what the optimum payload for their pits would be based on truck speed out of the the pit.

Another project was initiated to look at the impact of payload on truck speed up the ramps.

The study found that the two major ramps used had very different grade profiles with one ramp having a peak of 11.7% and the other 10.2%.

The site decided to for ease of message establish a single payload target to suit the steeper pit.

It was found that the optimum payload was 234 tonnes with loads over 240 tonnes being less desirable based on speed up ramp alone.

In addition to this through the MaxMine system the site found that the load bias and approach to the ramp also had a large impact on the overall up hill ramp speed.

Established And Prepared Plan?

The target payload went from 228 to 234.

The roll out plan to the Loading Team was to focus on Loads in Range, Load Bias and time taken to load.

This data was to be handed to the load operators on a daily basis.

A clear plan to push as many of the loads into the 234 to 240 tonne payload window.

Give the operators an understanding of who they could approach to assist them in improving their scores.

Roll Out and Maintain?

This plan was prepared with the assistance of the MaxMine coach.

Although the MaxMine site coach didn’t deliver the roll out they essentially created all the materials to deliver the roll out and supported the leaders through the process.

The Roll out was clear and concise and to the point.

Maintenance of the uplift is aided by the MaxMine system that easily integrates into daily site activities.

The performance is automatically tracked for the site and the MaxMine site coaches monitor and feedback to the site.

THE RESULTS

The changes in the crews behaviour was almost instantaneous.

Engagement with the MaxMine system and approach was very high.

Average payload went from 213 to 233, loading bias improved going from 80% to 90% loads in the optimum location on the tray.