Text Box: Kidd Creek Timmins, ON Rebuilding Cost Efficiency at Kidd Creek Nobody likes a long maintenance shutdown, especially the managers of the Falconbridge, Ltd. Kidd Creek mining operations in Timmins, Ontario. But when problems began with the machined fits on one of Kidd Creek's rod mill feed trunnion journals, a costly shutdown was just a matter of time. The fits had worn down enough to make the existing liner packing non-functional, and leakage of mill slurry into the journal area unavoidable. To prevent total destruction of the journal, the production line was shut down. A Team Durex competitor was brought in to line-bore out the fit area of the trunnion journal, and press in a new fit sleeve. The problem was fixed, but at a huge price: $30,000 plus the lost revenue from a three-week shutdown. That's when Marcel Rochon, the mill's maintenance superintendent, called Durex-Camline. After many discussions, Durex-Camline proposed developing a new fit with cast-in-place urethane. A Durex-Camline crew arrived at Kidd Creek, in November, 1986 to mold and cast urethane into the rod mill feed journal, which established a new fit and protective lining for the journal. The entire process took about 36 hours and cost only $5,000. The new fits matched the fits on the new trunnion liner designed and built by Durex-Camline. This new trunnion liner was a fabricated mild steel outer shell with a urethane cast-in lining and a cast urethane outer tapered fit. The Durex-Camline trunnion weighed about one-third of the original steel liner. Its 1/8-inch engineered "interference" fit provided a positive seal that prevented slurry leakage into the journal. When this trunnion liner needs to be rebuilt, it will be easily removed (about a two-hour job) and replaced with a rebuilt trunnion at a substantially lower cost than a new trunnion. Since 1986, Durex-Camline has established new fits on all Kidd Creek rod mill feed trunnion liners and trunnion journals. We've also provided additional innovative solutions, such as cast-in-place urethane discharge trunnion/lining systems. Over the past 12 years, Durex-Camline has worked with Kidd Creek to develop better trunnion liner designs and lining systems. And the ongoing trunnion lining rebuild effort is saving money, effort, and downtime.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Text Box: Inco Limited Copper Cliff, ON Trunnion Improvements Pay Off for Inco Limited's Clarabelle Mill The problem of heavy trunnions was weighing on Morn Bodson's mind back in February, 1987. Norm was the mill maintenance superintendent at Inco Limited's Clarabelle Mill at Copper Cliff, Ontario. He was trying to resolve a trunnion liner problem on Clarabelle's #3 rod milll. Norm wanted to reduce the overall weight of the original heavy cast Meehanite feed trunnion liner because the heavy weight trunnion was difficult to handle. He also wanted to increase the wear life of the liner, since the Meehanite liner lasted only two years before changeout was required. Norm called Durex-Camline. We first recommeded installing a liner to fit inside the main trunnion body sowe could evaluate the wear life of the proposed urethane lining material. (This test would be similar to the exisiting liner-liner system.) The liner was fabricated with a mild steel outer shell and cast urethane interior with bolt-in urethane spirals. To resist the impact of the rod grinding media inside the mill, bolt-on tips made of high Brinell hardness steel were engineered for the ends of the urethane spirals. This prototype liner—with half the weight of the original casting—was installed. After a year of continuous operation, the test was a success. Two years after the original installation, a Durex-Camline crew arrived at the Clarabelle site to replace the steel tips and repair the urethane lining system with a fast-curing, trowelable urethane compound. The repair work was performed during a regular planned maintenance shutdown, without removing the liner from the trunnion. After the first successful year of testing on the #3 rod mill, Norm discovered a more serious problem on the #2 rod mill. His millwrights reported that bolts were breaking off the trunnion mounting flange—a sign of trunnion fit problems. Durex-Camline recommended re-establishing the fits in the trunnion journal cavity with a castable urethane product. We had already performed this repair procedure successfully at Falconbridge, Limited's Kidd Creek operation in Timmins, Ontario. We designed a trunnion liner that combined the main trunnion body and the liner-liner concept all in one. This second-generation trunnion consisted of a mild steel fabrication with external urethane fits and internal segmented urethane lining system that bolted in. We also proposed removing the spirals from the trunnion liner. The goal was to increase the wear life of the trunnion lining by eliminating the parts of that wear most—the spirals and especially the steel tips. This left a smooth lining with no obstructions where specific wear patterns could develop. It also reduced the overall weight of the assembly. In February 1988, a Durex-Camline field crew was on-site at Clarabelle to establish the new trunnion journal fits and assist in the installation of the new trunnion liner. The entire operation took just 48 hours of a pre-planned shutdown. A year later, the same fit problem occurred in the #4 rod mill feed trunnion journal and it was repaired with the same methods used on the #2 mill. Durex-Camline introduced a third-generation trunnion liner at this time; a final design that blended the urethane shell lining and tip lining all in one segmented lining system. In May 1990, the #3 rod mill was reworked to establish urethane fits and standardize all of the trunnion liners. The #1 rod mill was also converted later in the year. With all four rod mills converted to identical Durex-Camline trunnion lining systems, Norm Bodson only had to stock one spare set of liners. But this inventory cost savings was just a fraction of the total cost savings achieved after the conversion. The new trunnions cost about 75% of the casting value, and half the weight, of the Meehanite castings they replaced. The cost of the conventional method of re-establishing trunnion journal fits (line-bore and install new steel bushings) cost at least $50,000 and two to three weeks of downtime per mill. The Durex-Camline solution cost about $10,000 and 48 hours of downtime per mill.   Case Histories: Rubber/Ceramic Screens / Rubber Screens / Urethane Screens / Wear Parts / Modular Systems - Snapdeck / Trommel Screens


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