How producers, contractors can partner to achieve plant design goals

By |  October 17, 2016

Every aggregate producer has process experience they’ve refined through trial and error over several years. Plant design plays a critical role, and as gradations and specifications of material requirements change, so does the plant design in order to meet these changes effectively.

Producers and any contractor assisting with plant design should work closely together every step of the way to ensure success. It is impossible for an engineering team to be knowledgeable about all regulations in every part of the country or the world, so they must rely heavily on the producer for assistance.

Additionally, each piece of equipment has its own unique features and processing abilities the engineering team should be aware of. This must be worked into the plant design in order for every piece of equipment to operate at its best. Knowledge of equipment features should be outlined so that the next phase of the processing chain is not hindered.

An outline of each piece of equipment’s features, processing abilities, maintenance requirements and operating requirements should be documented into a process flow.


Photo courtesy of McLanahan Corp.

Every aggregate plant should be designed for economical operation by a limited number of employees. Photos courtesy of McLanahan Corp.

Economics are an important part of any plant design. A plant/system should be designed for economical operation by a limited number of employees. Factors to be taken into consideration include the plant’s operational hours to achieve the desired capacity, as well as the projected life of the operation.

For example, if an expected life of a plant is 10 years at a 24/7 operation, then that plant runs four times more than a 40-hour-per-week operation. These considerations can ensure plants are designed to be economical for the producer. It should be noted that the most reliable equipment and components require less maintenance and tend to be more expensive.

Once the outlined flow has been solidified with the customer, the design portion of the engineering team’s job starts. The engineering team’s knowledge portfolio should include the following:

■ Knowledge of raw materials. Wear materials are better than they were 20 years ago and they continue to improve.
■ The location of plant fabrication relative to the producer’s operation, which will dictate the best plant design for economic transportation.
■ Evolving safety regulations. Accidents resulting in lawsuits have been the main driver for changes in safety regulations. The Mine Safety & Health Administration continually publishes accident reports, rulings, fines and regulation changes. The engineering team must review the reports in order to stay in tune with safety and guarding changes.
■ Some purchased components seem to be following the path of the automakers with a new model every year and no interchangeable components. What was used successfully last year might not be available this year or be able to be used without modification, and the engineering team should be up-to-date on these changes.
■ The static and dynamic forces of equipment used in the system differ between types of equipment. Knowledge of these forces and differences allows the engineering team to economically design the structure for stability.


It is vital that the functions and features of the equipment designed into the plant interact with other equipment and components in a functional way. Jaw and impact crushers both crush material, but they crush materials in different ways and require different designs of feed chutes and discharge chutes to be successful.

Dust and air-flow controls are also handled in different manners. The dynamic loads vary greatly and require different considerations in the structure supporting and surrounding these crushers.
Operation and maintenance access can vary between processing equipment. Ease of maintenance access for changing wear items and making adjustments is one way of providing a user-friendly plant design. If the operators and maintenance personnel are happy and maintenance time is low, then the producer is operating in an economical manner and will be more profitable.

Automation of processing and vital signs allow for better uptime and less human intervention. The degree of automation and remote monitoring provided to the producer should result in a return on investment.

Use of automation devices varies greatly between producers, so detailed discussions between the engineering team and the producer is recommended for the best outcome.

Portable plant design requirements and stationary plant design requirements are similar with regard to the features and operation of the equipment used, but put more constraints into the design.

The engineering team and producer must consider compromises throughout the plant-design process in order to achieve the package of size and weight constraints. Since there are no national governing constraints for portable crushing plants, every state has its own regulations, and all of the regulations vary. One design may not work in every state, and engineering teams should be able to work around the specific requirements and regulations.

In summary, a successful engineering team is very similar to an orchestra conductor.

A conductor must know the music of each instrument and coordinate all the instruments to perform together. Similarly, an engineering team needs to have strong knowledge of all of the pieces of a processing plant and work with the producer to coordinate the assembly and use of those parts.

The ultimate goal is more uptime and higher profits.

Jeff High is global product manager for crushing and screening at McLanahan Corp.

Photo courtesy of McLanahan Corp.

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