The Superior Terminal facility in Wisconsin, owned by Detroit Edison’s Midwest Energy Resources Co., first opened to traffic in 1976.
The Midwest Energy Resources Co. (MERC) Superior Terminal facility was commissioned in 1976 and it opened up a new world for the Powder River Basin’s vast coal output and has since been a new shipment avenue for many other coal mine operators.
The vast 200-acre facility on St. Louis Bay in Superior, Wisconsin, is the largest-capacity coal transshipment facility on the Great Lakes, shipping out more coal on an annual basis than all of the other dock facilities in the region combined.
The sheer size of MERC’s Superior complex, even prior to the renovations, certainly puts things into perspective. Last December, the dock shipped its 500 millionth ton of coal when it loaded the Interlake Steamship Co.’s M/V Paul R. Tregurtha for the DTE Electric Co. The milestone came about six years after marking its 400 millionth ton. MERC had also loaded its 10,000th vessel a month earlier.
With a 3.5-mile-long perimeter and double-loop track for double-train capacity, it can easily service its connections to both the BNSF and Union Pacific railways with 123-car unit trains at 120 tons per car. Crews there keep up the pace well; in 2006, Superior hit its record for trains unloaded in one season with 1,521. Its single-car rotary car dumper has an availability average of more than 98% thanks to a 24-hour maintenance crew it keeps at the ready. All told, its unloading capacity is 5,000 tph rail to ground, and 11,500 tons per hour (tph) on the vessel loading side.
Additionally, the largest vessels on the Great Lakes, the Super Laker class, have no trouble docking at Superior, making it among the most flexible facilities of its kind. Its dock extends 1,200 feet, allowing access to the 1,000-ft-long vessels (each with a capacity of up to 68,000 t). While coal is waiting to be shipped, Superior offers 5 million t of stockpile capacity. A fleet of six Cat D11 dozers and two Cat 657 scrapers manage the stockpile.
Superior’s director of terminal operations, Marshall Elder, stressed that MERC has always held a strong dedication to environmental controls, including an extensive dust control system (including 30 water cannons, a water truck fleet and other controls), water management/reuse via a water treatment plant, telescoping discharge chutes and a baghouse dust collection system. It operates with the goals of retaining and gaining efficiency to keep costs in line with other fuels and other transportation systems, as well as overall continuous improvement, he added.
An important factor to note: Superior operates at these high levels and with these capacity numbers while working through the tough weather and other conditions that come with life in the northern Wisconsin/Minnesota region.
In addition to that, there is an outage each year while Lake Superior is frozen over — typically early January to mid-March. Elder said it uses a majority of that time to work on its systems, even if conditions are harsh and the mercury dips below zero. Historically, the earliest start to Superior’s shipping season has been March 14, which occurred in 2006. Its latest end to the season was marked in 2004, when it idled operations on January 18.
In 1992, and again in 2002, MERC undertook terminal physical additions and modifications along with improvements to control systems in order to increase its annual throughput capacity from 12 million tons per year (tpy) to, ultimately, 25.5 million tpy. These throughput capacity improvements were performed to keep abreast with market demands.
The terminal set out to achieve three main goals with the improvements: again, to increase overall capacity from by 13.5 million tpy; to increase unloading capacity from 3,600 tph to 5,000 tph and also to maintain overall terminal reliability and performance at the elevated annual throughput levels.
“The ship loading rate was increased from 10,500 tph to 11,500 tph, in the late 1970s by adding a third plow feeder to each of the then two-plow feeder trains,” Elder said. “This provided the capacity to reach the desired rate without overstressing the original two-plow feeder configuration at each reclaim location. A third-plow feeder train (reclaim location) was added in 1992 to increase the terminal’s capacity to handle a larger variety of coals.”
At the car dumper, cycle times were crucial, and post-upgrade, the cycle times rose from 115 seconds per car to 86 seconds per car. MERC said it was able to make that goal by upgrading the car dumper drives to flux vector drives and also by installing faster-acting wheel clamps in lieu of the original wheel chock system. It also upgraded hydraulics to gain car clamp speed and increased the indexer speed by installing a positioner optimization controller (POC) for more precise control based on load.
The indexer drives were also upgraded to improve efficiency in control, and the indexer gearbox was replaced with a newer, upgraded version that could handle the load.
“Feeder speed was increased to accommodate the increased dumping times,” Elder said, noting that every second gained in turn increases the unloading rate by approximately 50 tph.
MERC made initial modifications to the unloading system as part of the unloading chute renovations. Overland Conveyor was brought in to computer-model the chutes for optimum flow and configuration. A local engineering firm completed the resulting design and a local fabrication shop and contractor performed the actual construction and installation.
Location: Superior, Wisconsin
Owner: Midwest Energy Resources Co. (MERC)
Parent company: Detroit Edison (DE)
Land size: 200 acres
Perimeter track: 3.5 miles
Unloading capacity: 5,000 tons per hour (rail to ground)
Loading capacity: 11,500 tons per hour
Annual handling capacity (permitted): 25.5 million tons
Ground storage: 5 million tons
Record annual shipment: 22,333,944 tons (2008)
“The chute designs were challenging due to short drops between conveyors at the transition points, coupled with [the] overall design flow increase from 3,600 to 5,000 tph,” Elder said. He added that those obstacles were overcome with innovative features such as movable two-position chute feeding, a bidirectional reversing conveyor, and a double spoon chute design discharge of the feeders below the car dumper hoppers. A hood to house the new technology was also added.
With the new chute design completed and the infrastructure in place, Superior immediately realized an increase in rate of 200 tph. It also saw reductions in component wear, Elder said.
“There was a dramatic improvement in belt cover rubber wear,” he said. “The most notable was the reversing conveyor, which feeds the telescopic chutes going to the stockpile. Historically this belt had to be replaced about every two years due to top cover rubber wear. After the chute modifications, this belt ran for seven years and was replaced due to mechanical damage, but still had life in the cover rubber.”
Additionally, the improvements virtually eliminated another standing issue: coal slipping on the 17˚-decline takeaway belt in the winter. MERC also reported less dust at transition points because of a reduction in fracturing at those locations.
Elder noted that not all of the changes were incorporated at once; the work was, in fact, done in stages over a multiyear period.
“By proceeding in this staged fashion we were able to achieve our goal without increasing the unloading system conveyor belt system from 60 in. to 66 in., which was what the design called for.”
The chutes at the loading conveyor system were designed with the same computer modeling technology, with all stages from modeling and design to installation completed by Martin Engineering. Both Elder and Martin spokesperson Andy Marti noted that, from a project management standpoint, following that plan made for a much smoother placement.
While Elder said that MERC has shared the pressure felt by many of its contemporaries with regards to changing regulations and a push to phase out fossil fuels for electricity generation, he said the facility is dedicated to remaining competitive. Much of that will be achieved by maintaining Superior’s position as an efficient, low-cost operation. He noted that its workforce intends to continue that by applying continuous improvement principals in process design review and making appropriate changes for improvements.
“We also have a longstanding, valued and empowered workforce of 86 employees (54 of which are represented by the ILA union) who are engaged and dedicated to safely accomplishing our goals and providing those cost-effective services to our customers,” he said. “Our primary goal continues to be the best operated terminal in the world.”
Adaptation has been key for coal in this volatile market, and that certainly also applies to the port system. It has been doing outreach for other non-traditional coal markets, including Europe via the St. Lawrence Seaway.
It also has bolstered its concentration on having a strong proactive preventative maintenance program. Elder said the secret to its success has been dedicating time and resources to cover all operating equipment, which is one of the reasons its high level of availability on a consistent basis.
Some of its preventative maintenance practices have included, and continue to include, routine inspections and testing to investments in major equipment overhauls; 2016 is the second year of MERC’s major investment program to overhaul and upgrade the original reclaim plow feeders, of which there are three sets of three at Superior, each with the power to store and reclaim nine kinds of coal and blend up to three kinds of coal.