Measuring roadway development by metres per shift is fraught with inconsistency. A far better alternative is to measure performance over a full panel cycle.

 

Improving roadway development rates at longwall mines is dependent on being able to measure and benchmark performance. The most typical measurement of performance continues to be metres per shift - also the yardstick used by Australia's Longwalls in a March 2000 statistical review on roadway development.

 

Most longwall operators will, however, readily admit that development performance is ad hoc - there is no guarantee that a crew which achieves 20m one day will not drop to 3m the next. This means that setting targets and budgets becomes a moving feast with little hope of consistent performance.

 

As noted in Part One of this series, the October 1999 Australian Coal Association Research Program (ACARP) report, 'Implementation of Roadway Development Strategy', written by Michael Kelly, argued that "emphasising metres per shift is probably the most damaging benchmark in our industry". While longwall mines continue to judge themselves by this measure, there is widespread acknowledgement that metres/shift often delivers inconsistent data.

 

The reasons for this are to do with the wide range of activities performed during a shift. One shift may be a maintenance shift, another may involve a belt move, while a third may be unmanned. The challenge becomes how to average out performance by shift.

 

Some mines report metres per shift only when coal is cut, while others measure performance every time men are in the panel, regardless of whether coal is being cut or not. Others discount travel time from the surface - usually mines with poorer travel systems.

 

In other words, the system of measurement across the industry uses different parameters - a bit like comparing apples with pears.

 

Kelly argues in the report that metres/shift does not recognise natural variation and encourages short-term performance at the expense of longer-term sustained performance improvement and cycles beyond the immediate face cycles. "It is the reason many mines' peak development shift performance is 300% higher than their average."

 

The alternative, according to the report, is to measure roadway performance over a full face-pillar-panel cycle. An average full pillar cycle is around 240m of development and may take about 13 shifts to complete. At every mine there are activities that occur at four distinct hierarchies that impact upon roadway development rates. These hierarchies are:

 

face activities (eg cutting and loading);

pillar activities (eg service extensions);

panel activities (eg panel setup and completion);

and lastly, whole of mine issues such as exploration, maintenance and rosters.

 

Unless the interaction of these activities is understood and managed properly, there will be a negative impact on rates.

 

Whilst many mines recognize the impact of pillar cycles, an interim ACARP report during the research phase of the project found that at many mines the existence of the pillar cycle was not readily accepted.

 

Typically at these mines the outcome is that the cycle consists of a series of disconnected activities that have very poor interfaces, interaction delays and slow learning curves.

 

Said Kelly: "Everyone goes straight to the development face and looks at how the mine is cutting coal, and they say if we can cut faster we can get more metres. Everything behind that - the supply system, the roadway maintenance, roadway building, consistency of labour allocation, team building within groups - all these extensions are not focused on."

 

A full panel cycle includes "the setting up and driveage of mains, gateroad panel breakaway, set up of gateroad panel, driveage of gateroad, driveage of face heading and panel overdrive, interaction requirements with the longwall installation, removal and equipment overhaul and start again".

 

Effective KPIs for roadway development, therefore, may include face cycle times (uptime rates in metres per hour), pillar cycle times, metres per week and cutting hours per week. They do not include metres per shift.

 

The report acknowledges that the panel cycle is "difficult to portray because of the complex interactions between planning, operations, and maintenance groups, and especially because of the complexity of communication, monitoring and feedback systems required".

 

An interesting finding was that nine of 15 mines in the initial study suffered from negative interactions between mains development and gateroad development, due mostly to lack of pit room.

 

One significant problem with benchmarking roadway development performance is the ongoing philosophy that targets should be management driven. CEOs still like to see shiftly metre reports. In addition, applying the systems approach requires a perceived relinquishment of control and, as mentioned in Part One, this is something middle managers resist.

 

Said Kelly: "Some mines translate required metres on a yearly basis to daily and then to shift rates. They present the guys in development with a required average for them to meet on a shiftly basis. It's a budget metreage, not an operational metreage."

 

Historically, however, shift averages will always be just under shift targets. If people get over target they feel they have done their job for the day. Changing the emphasis on targets to an emphasis on process is difficult to achieve, however. At one mine an interim step was to change from shift performance to a "pillar a week".

 

The report commented: "While it could be argued this is still a target that does not promote process improvement, it was recognised as an interim step between shift targets and process targets of metres advance per operating hour and operating hours per shift."

 

While, on the one hand, the systems approach calls for an acknowledgement of the interaction that makes up the whole process, it is also important to look at development in small units, that is, units smaller than shifts. This means tracking development metres per operating hour every shift.

 

The unions have resisted this, partially because of perceptions that it measures how hard people are working, but this approach is being looked at increasingly. Mines such as Newlands in Queensland's Bowen Basin recently adopted this method and are consistently achieving among the highest development rates in Australia.

 

Typically, it would appear that focusing on hourly rates seems to make people understand the process and what is slowing them down.

 

An answer developed by some mines has been to pay bonuses on development metres - effectively, a punitive/reward system. In the context of a systems approach this may not be the best response because it separates a single issue from the broader context.