Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/841719
14 AGGREGATES MANAGER / July 2017 PLANT PROFILE Richards Spur is subject to the electric company's Peak Power program, which determines when the shifts can run. The quarry can't run production be- tween 2 and 9 p.m. from June through September, so that time slot is left for maintenance. Blasting, which is contracted out to Buckley Powder, takes place twice a week in multiple places for more flexibility, especially when it comes to the weather. Two loaders keep five haul trucks loaded with material and on the move. The trucks dump the material into a gyratory crusher in the primary plant. From there, the crushed rock is conveyed up to the primary screen tower and separated to run through two different processing plants. The original processing plant began production in November 1951. "In the surge building, we're running seven Symons cone crushers, which are 4-foot, 4 1/4-foot, and 5 1/2-foot crushers," Barks notes. "In our mill building, we have 14 screen units with 10 on top. This is a fractionated plant that Roger Dolese designed. It's a little different from other fractionated plants. A lot of them are built horizontally, but this one is built vertically. The 10 screens on top separate the rock by size and put it into hoppers. Down below, the blending conveyors blend all that rock back together to meet a gradation and drop it down into the bottom bins where haul trucks load up and put it into stockpiles. The nice thing about this system is that we can turn the dial and turn the conveyor down to adjust the blend." A catwalk runs between the bins in the mill building. In 1951, someone walked up and down that catwalk. When a truck pulled up under a bin, that person would pull a lever to open the clamshell gates to load the truck. In 2017, it's done the same way. The Phase I plant, which was built in 2003, is a more traditional plant with a 7-foot standard and 7-foot shorthead crusher, and two 8 x 20 horizontal screens. The main difference between the two plants is that, to adjust the blend in the Phase I plant, the screens must be changed out. A separate area at the back of the quarry is where rip rap is made. "When we blast here, we're actually blasting for rip rap," Barks explains. "The blasting pattern is a little different from our normal production shots." A loader picks up the shot rock and drops it into a Nirox trommel that sepa- rates the rip rap into four different sizes The mill building is a vertically built fractionated plant with 14 screen units. The 10 screens on top separate the rock, blending conveyors blend the rock back together and drop it into loadout bins, where haul trucks load up and carry it to the stockpiles. At the back of the pit, a portable Nirox trommel is used to make rip rap in sizes ranging from 12-inch aggregate to 30-inch plus.