The Plant

There is no PLC (programmable logic controller) on the plant, but all wiring is interlocked. And a particular startup sequence must be followed. So, before the crusher starts, the conveyor before it has to be running; and vice versa. Although this is less sophisticated, the system works well.

Most of the plant consists of equipment taken out of an older plant on site that was moved to reach reserves. Heavy maintenance also was required, as were some modifications to better accommodate the slurry from the dredge. This included the addition of pleated belts on a couple of the incline conveyors to help move material up to the feed boxes.

“Everything was reworked,” Goessling says. This included dismantling the old plant, preparing the new location, transporting it and re-engineering it. Most of the fabrication was done in house and so was a lot of the electrical work. Overall it was an eight-month process that required the help of six or seven of their best employees.

This plant, from the perspective of the control tower, begins at the feed hopper, a 6- × 16-foot Allis Chalmers. It is a triple deck, but typically only one screen is used. The oversize feeds a APK-30 Hazemag rotary impact crusher. This crusher handles about 50 tph of material.

This and much of the other equipment on the plant is more than 20 years old. And much of it will likely live to see another operation as reserves are exhausted in about 15 years. It's all about good maintenance.

For the crusher, blow bars are rotated every 200 hours. Typically, four rotations are achieved before replacements are needed. Wear aprons generally last one season and are replaced during the off season.

The crusher's feed conveyor is equipped with a metal detector to remove tramp iron. When metal is present, a brake motor automatically stops the material flow, reverses and dumps the metal onto the ground. Goessling says old dragline teeth, nuts and bolts, as well as angle iron are common.

Moving Material

Crushed material is conveyed to a different screen; oversize is rejected. The crusher is on a closed circuit and produces a state-spec 304, which is provided to road and paving contractors. Goessling says this compactible material also is good for gravel roads.

The undersize is transferred to an 8- × 20-foot triple-deck wet screen, which separates 57s and 8s. Material is washed with 2,600 gpm from the lake. The grits, a small pea gravel blended with a coarse sand, and the concrete sand is the undersize that is discharged into a twin 44-inch Greystone dewatering screw. A slurry pump for the weir water takes material to a 20-inch Krebs cyclone, which is where the fine brick sand is removed.

“Material is untouched by any equipment other than the land conveyors,” Goessling says. “And it is falling onto the ground as finished product.”

This was a big step in the right direction, as the last plant relied heavily on haul trucks to move material. It also eliminated load cranes and at least two wheel loaders from the process. This means considerable savings have been made — cutting costs in fuel, tires and manpower. Also, the entire property has already been stripped of its overburden, further degrading the need for draglines and scrapers.

The stockpiles are the first point where mobile equipment enters the process. All material is loaded with wheel loaders. And trucks follow a simple loop in and out of the plant. Goessling says this also was a marked improvement over the old plant. Before the new design, trucks had to drive clear across to the other end of the property and return to the Thurman scale by the same road.

Welch owns and operates its own dump trucks but also contracts out to other trucking companies. All dispatching is done over the phone from a central office, and a scale operator waits with a ticket as truckers exit. Welch services the entire Cincinnati area, spilling into portions of Indiana and Kentucky. This includes natural concrete and mason sand, and base materials for various construction projects. Much of the material is now being used for commercial developments.

Welch and all other sand and gravel operations in the area continue to suffer from a deflated housing market. Some of Welch's competition has shut down operations to wait out the storm. Goessling says the company has been able to keep its gates open because it has no stockholders to answer to. “So when a hard time like this hits, we can just ride the storm out,” he says. “We know it's going to pick back up.”

“When we bought the first clamshell dredge, they gave me the responsibility to erect it and learn how to work on it,” Goessling says. “Then I inherited the gravel plants and we fixed bottlenecks to increase production.”

Take a look at Welch's riverside operation