30 days in the hole: West Coast Aggregates rebuilds a plant from the ground up in about a month, and then gets right back to business

Pit & Quarry, March, 2004 by Mark S. Kuhar

For many aggregates operations, shutting down a plant for a month would be the kiss of death. But when Dick DeAtley, president of West Coast Aggregates decided to upgrade the company's Lexington Quarry operation in Los Gatos, Calif., that's exactly what he did. He promised production would be back on-line in about a month, and he made good on that promise.

"There were times when I wondered just what I was getting myself into," DeAtley says. "But in the end, it all worked out. We had a great crew and they worked hard to get the plant done on time."

A man with a plan

Tearing down a plant and starting almost from scratch required extensive advance planning. The team at Lexington Quarry took the time to explore many options before deciding on what they wanted to build. Taking the time to do it right was an important consideration. The entire process took about a year from planning to construction.

First, the operations team made a list of what products they wanted to make; their target for tons-per-hour (300-325 tph); and a list of equipment they wanted to use. "We also went to suppliers and distributors to get ideas," Tona says. "We looked at other plants, too. We got input from a lot of people."

One of the big things the company wanted to accomplish was to incorporate a wash plant into the operation. Previously, they had only engaged in dry processing.

"With the old plant, we couldn't meet state specs anymore," says Joe Tona, operations manager. "And with the specs getting tighter and tighter, the only cure was to build a new plant that gave us the ability to make washed products."

One very big issue for the new plant was what to do with the waste water from the new wash plant. "This is a smaller quarry," DeAtley says. "There was no space to build a settling pond. After much research, we decided to install a thickener and a belt press."

Planning for the plant

Preparations for the building of the new plant started with the stockpiling of material so they would have something to sell during the conversion. "We ran as much material onto the ground as possible," DeAtley says.

Then they reached the point of no return. They began to dismantle the old plant. "We met with contractors in advance to coordinate the schedule," DeAtley says. "We decided that this job was going to be done in 30 days, so we sketched out a timetable"

The project was to begin in April 2003, with seven days allotted to the demolition of the old plant, seven days for pouring concrete and two weeks for construction of the new plant.

It was a struggle, with workers often toiling in rainy conditions. West Coast Aggregates employees did the tear-down. Concrete for the footings was poured by Albanese Concrete. Corey Delta did the erection and fabrication work. Local distributor California Screen and Conveyor Inc. supplied all of the equipment for the plant, with Ron Detimar taking the lead to make sure all of West Coast Aggregate's needs were met.

When the dust cleared 34 days later, West Coast Aggregates was ready to go back to business with a new plant that

featured new equipment and some of the equipment from the old plant, as well.

Going with the flow

Production at Lexington Quarry begins with a Caterpillar D9N dozer, which rips material from the quarry face. A Caterpillar 980G loader cycles between the face and plant, where it dumps material into a variable speed vibratory feeder.

Material passes over a small, 4-in. grizzly, and overs go to a Pioneer primary jaw crusher. From the jaw underbelt, material goes to a triple-deck 5 x 14-ft. El-Jay screen, which scalps out a gabion product. All 2 x 4-in. material goes to a blend feeder then to an HP 300 cone, and 2-in. minus material goes to a McLanahan scrubber/coarse conditioner.

After the product is scrubbed, it is sent to a 6 x 16-ft. Deister triple-deck screen. Overs go back to the blend feeder, while the middle deck makes a 1 x 2-in. railroad ballast.

All 3/8-in. minus goes to the cyclone sand plant, while material 3/8 x 1-in. goes to the next screen, a second 6 x 16-ft.

There, material is split into three sizes, a 3/4-in. drain rock from the top deck, 1/2 x 3/4-in. concrete or asphalt aggregate from the middle deck and a 3/8-in. chip used for asphalt or chip seal from the bottom deck. Thoughs go to an LPT cyclone sand plant.

Stirring up a cyclone

The cyclone removes material that is 200-300 minus, while sand passes over a 5 x 12-ft. LPT dewatering screen. The final sand product has a 12 percent moisture content.

The 200-300 minus material goes to a 14 x 30-ft. LPT thickener tank. As mud is thickened, the BDP belt press squeezes out a 3/8-in. sheet of material, which breaks up into cakes.

All in all, Lexington Quarry makes seven different products. The cake product from the belt press is being used to fill excavated trenches. These will be planted over with trees, plants and other foliage to help with erosion. Eventually it is hoped the cakes can be used to make a saleable topsoil blend.

Looking to the future

Lexington Quarry hopes its new operation will help meet a pressing need for material in its market. "There are shortages of material in this area, concrete sand in particular," DeAtley says. "We hope to make 450,000 tpy of sand from this plant. All of it will be sold to customers in the South Bay area.