There are multiple routes to climb Mt. Everest. But given the conditions on the mountain, there is one route that provides far better success to climbers hoping to reach the summit. Chances of success for those who attempt other paths are far less.
The same logic applies to producers and material processing.
The reality is that the crushers and screens producing the same end-products are packaged in a variety of mobile and stationary configurations, each providing a unique path with distinct advantages depending on the wants and needs of the business. The smart producer will transcend the biased arguments in an unbiased technical analysis and choose the safest path.
First, the obvious: Are we planning for one or more locations? While we may not require a portable system to process material in a single location, or that it would make sense to acquire a stationary system to service multiple deposits, the market has still flooded us with many options to consider.
Custom stationary
When the plan is to install a permanent system that won’t be removed until a quarry runs dry or the equipment falters, a custom-engineered system is the usual selection. Hoppers can be designed to accommodate the loading fleet and cycle times. Crushers and screens can be matched to suit material characteristics and productivity requirements.
If designed and maintained properly, the payoff should be the highest possible level of uptime, production and efficiency.
The trade-offs are not insignificant. The time to engineer, permit and install stationary systems can be very extensive, and the size of the crew to operate and maintain such plants can be higher, as well. This will contribute to the overhead burden.
Skid/modular stationary
As the name implies, these systems are stationary structures on “skids.” Skid/modular plants can be towed around jobsites for repositioning. They are favorable against frost heave. They can also typically be disassembled relatively easily for relocation, although not as economically as a portable system.
In addition, these plants typically take less time to install – saving lost production – and they cost less compared with more elaborate, engineered stationary and portable systems.
However, skid/modular plants are typically simplistic in design in terms of controls. They are limited in terms of the size of crusher, hopper and other components they can accommodate.
As it pertains to any stationary system, the paradigm has shifted in that with rapidly changing market dynamics and increased competitive pressure, today’s producers often need to be more nimble. Permanent, fixed plants by design do not lend themselves to adjusting for capacity variances, new product specifications and so forth.
Mobile processing
If a producer needs to service multiple locations, then deciding whether the machinery should be tracked or wheeled – and to what degree the equipment needs to be mobile – should be based on an analysis of the producer’s production requirements.
Wheeled plants. Production is the economic sponge that absorbs all the costs of operating a plant. The highest cost in any portable operation comes in the form of lost revenue. A portable plant that is not operating is still incurring costs in the form of wages, trucking and so forth. So the longer a plant is down between moves and setup, the more the downtime costs the operation. Producers requiring high production processing between multiple locations should invest in highly mobile portable plants designed to be set and moved as quickly as possible.
Tracked plants. They can quickly be positioned and operational in minutes. User-friendly controls are easy to operate and don’t require a high level of tribal knowledge. Mobile plants feed one another with clean transitions, eliminating transfer conveyors. They don’t require a large operating footprint, making them perfect for tight jobsites. Self-contained power units allow them to work in remote regions, too.
However, compact packaging can add service complexity, and diesel engines demand attention. Accordingly, track systems generally provide 5 to 10 percent less uptime than portable equipment, and components that are sized to facilitate track mobility typically restrain track plant production.
When does one select a track system over a wheel system? In the absence of the obvious deciding factor, the economics should be weighed. The deciding factors should be absorption of the indirect burden costs and the variable cost per ton.
Takeaways
Exceptions to these guidelines exist. When looking to design your next system, collaborate with a trusted partner who is not obligated to promote a specific technology style. Sometimes we all need a trusted climbing guide.
Use this guide to choose what type of equipment you should purchase. Download this chart here.
Paul Smith is international marketing manager for Astec’s Aggregate and Mining Group. He can be reached at psmith@astecindustries.com.