Miski Mayo, a subsidiary of the Mosaic Company — the world’s leading integrated producer and marketer of concentrated phosphate and potash, mines phosphoric rock at their Bayóvar 2 mine in the Sechura Desert of Peru. The material mined at Bayóvar provides high levels of phosphate and calcium that help correct soil acidity levels. These offer a high level of agricultural efficiency and are certified for organic cultivation. Miski Mayo’s phosphates are shipped all over the world, and they strive for their product to meet the highest quality and safety standards to achieve a strong relationship with their customers.
Case Studies
Challenge
Miski Mayo’s phosphate production process entails first extracting the phosphoric rock. After the ore is mined, Miski Mayo treats it in a concentrator plant prior to drying and shipping. The concentrator plant consists of two production lines, each containing, among other equipment, a 12’x50’ (3.6 m x 15.2 m) McLanahan Rotary Scrubber.
McLanahan Rotary Scrubbers remove deleterious materials such as water-soluble clays and coatings from ore feeds. Through the continuous lifting and dropping action that takes place inside the drums, the material tumbles on itself. The softer materials are broken down and dissolved into the solution of water added with the feed.
“The McLanahan drums fulfill an important function in our operation of degrading the material from larger diameter to smaller diameter to obtain a greater phosphate recovery,” said Nel Moreno, Maintenance Technician at Miski Mayo.
The Rotary Scrubber drums turn via trunnion rollers supporting the cylinder ends, which are equipped with renewable steel tires. In 2018, the tires on the Rotary Scrubbers at Miski Mayo reached their maximum wear limit and needed to be replaced. Miski Mayo had no experience replacing these components, so they contacted McLanahan’s representative in Peru for assistance.
Solution
“McLanahan’s response was immediate,” said Manuel Chappilliquen, Maintenance Technician at Miski Mayo.
Two McLanahan representatives, a Senior Field Service Technician from McLanahan’s headquarters in Hollidaysburg, Pa., USA, and the Product Manager from McLanahan’s Chile office, traveled to the Bayóvar 2 mine to assist with the replacement.
“McLanahan had a very important role in the replacement of the tire,” said Julio Perettel, Maintenance Superintendent at Miski Mayo. “We did not know the procedure, and we did not have the necessary equipment to do the replacement.”
The replacement required an entire plant shutdown, as well as the removal of several pieces of upstream equipment that were in operation. Before McLanahan arrived, Miski Mayo began preparing for the procedure by cutting the tire and welding lifting points to the tire so that it could be easily removed after the second cut was made.
“Our biggest challenge was cutting the existing tire and then placing the accessories to help us move components and make the assembly,” said Mr. Perettel.
Once the worn tire was removed, the new tire was lifted into position, aligned with the drum and mounted on jig assemblies close to the base of the tire. The new tire was positioned over the jig assemblies and prepared for induction heat treatment, which would expand it to fit the rim.
Induction heat treating provides a controlled and consistent heating pattern to bond conductive materials via electromagnetic currents inside the object. At the Bayóvar 2 mine, this was achieved by wrapping the outer diameter of the tire with two layers of insulating blankets. Thermocouples were installed under the blankets so that the temperature could be monitored and recorded once the tire began to heat. The tire was then wrapped with heating cables, and the induction equipment was programmed to start heating the tire.
While the tire was heating, stop blocks were attached to the back of the rim to prevent the new tire from sliding past the rim during installation. Once the tire had reached desired temperature, it was slid onto the rim and allowed to cool down, which would shrink the tire to fit tightly to the rim of the drum. After it had cooled down, the tire was perfectly attached to the rim.
Results
With the collaborative effort from McLanahan and Miski Mayo, the tire replacement was carried out smoothly and efficiently.
“It took us time to plan the purchase of spare parts and the tools needed for the service, but everything turned out successfully,” Mr. Chappilliquen said.
Mr. Perettel highlighted that the Rotary Scrubbers have been working optimally since McLanahan and Miski Mayo performed the tire replacement. They continue to help Miski Mayo meet their goal of producing high-quality phosphates.
“We are very pleased with McLanahan’s service,” said Mr. Perettel. “The replacement of the tire was a great challenge, but we met the deadlines and had no major inconveniences in the aspect of safety.”
