Lean Method to Identify Improvements for Operation Control at Quarry Sites

Abstract

The operation of Quarry and Aggregate sites are similar to factory production, since it contains sequential production processes, tasks and activities to produce the output product. Compared to the plant though, the quarry processes are generally not synchronized and controlled towards the overall throughput of the site in real time. Some quarries control parts of the production but do generally not utilize real-time technologies for the whole site and all its activities. This fact indicates a general improvement potential in increased productivity at quarry sites, but also unsolved challenges for the same reason. The main contribution of this paper is the presentation of a Lean based method for how to describe the processes to identify control improvement potential within a site. The aim of the identified improvements is to increase overall site productivity by optimizing site, fleet and machine utilization towards the overall throughput, and minimizing operational expenses and inventories. Further the paper exemplifies the method's usability with field studies at operational quarry plants successfully identifying and quantifying potential wastes and improvements. In addition the identified productivity improvements based on increased control and automation indicate challenges and needs in wireless communication and sensing technologies.

Energy savings by wireless control of speed, scheduling and travel times for hauling operation

“…In [2], it was described that waiting can occur at loading and unloading by an average of 30% of the operating time for haulers. In Figure 4 the increase of travel time by 37% from 78 s at top speed to 107 s would decrease the fuel consumption from start to stop by nearly 25%.…”

“…The two test configurations did not show exactly the same results but the tendency is the same in terms of fuel savings of about 20-30% with increased travel time of between 30-37%. In [2] it was shown that quarry sites can have up to 30% wastes in waiting times and unnecessary stops. In addition, [8] shows that communication coverage can be obtained with wireless ad-hoc communication technologies between mobile machines in a quarry environment.…”

“…In [2], it was concluded that waiting time often occurs in real world quarry operation as well as unnecessary stops due to narrow roads. The fuel measurements in this paper show that it is not always better to decrease speed to improve fuel efficiency.…”

“…For the transport to the crusher activity, it is common that sites have a large amount of unnecessary stops during transport operation due to occasionally narrow meeting areas, and waiting times caused by overcapacities and uneven mass processing capacities [2]. Based on the use of different machine types and performance, the waiting times may occur both at loading of raw material and at unloading at the crusher.…”

“…Based on the use of different machine types and performance, the waiting times may occur both at loading of raw material and at unloading at the crusher. In [2], it has been stated that average waiting times may be up to 30% of the total transport cycle time.…”