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5. Chemical Handling Systems and Containment <br />All chemicals are currently stored on site and housed in a separate partition of the filter building. This is called <br />the reagent room or chemical storage area. The plan view of the filter building and its associated environmental <br />controls are shown in Map 1. <br />As described in Exhibit T of the permit, the northeast part of the Filter Building houses the chemical storage <br />area. A garage door can be opened to allow chemicals to be brought into the building and to allow empty <br />containers to be taken out. Chemicals arrive in secured sacks, metal drums or plastic totes which have a <br />protective metal mesh around them. The chemical list was previously revised and is included in this section for <br />convenience. The maximum amount stored is also included. The chemical storage area is also next to two large <br />18,000 gallon tanks; one is for tailings slurry and the other is for process water. The floor of the chemical storage <br />area is 6" reinforced concrete slab with an epoxy layer seal on top to prevent damage to the concrete if a spill <br />occurs. The three vertical concrete walls of the chemical storage area are 6" thick and are also epoxied. The <br />entrance wall with garage door achieves containment using a 12" thick by 6" tall tapered concrete and epoxied <br />curb. Given the dimensions of the walled area: 27 feet x 56 feet x 6" height, the available volume is 756 cubic <br />feet or 5,655 gallons. The maximum liquid container in the storage area is 375 gallons of liquid sodium <br />hydroxide, which is 50.1 cubic feet, therefore, the vertical walled area is more than adequate to contain the full <br />volume from the maximum size tank rupture. In actuality, it can hold 15 times this volume. A telehandler or <br />skidsteer is used to transfer chemicals from the outside area to the chemical storage area through the garage <br />door. The vertical wall at the garage door opening is protected from damage during chemical transfer by slanted <br />concrete to allow the tires of the machinery to cross over the wall. A sump was installed in the floor of the <br />chemical storage area which has a level controlled sump pump. If any water, slurry or liquid chemical is spilled in <br />the storage area, it will flow to the sump, where it will be pumped back to the 18,000 gallon process water tank <br />or reagent mixing tanks based on the event. <br />There is an additional protection against spills leaving the filter building area, which is a concrete apron of 78 <br />feet long and 9-10 feet wide. The thickness of the reinforced concrete is 6 inches. A swale was formed in this <br />concrete which is 6" to 8" deep and leads to a sump on the east side of the building. A level controlled pump of <br />300 gpm capacity has been installed in this sump to automatically pump any liquids or slurry back to the <br />thickener or 18,000 gallon slurry tank. The apron can capture any leakage from the chemical storage garage <br />door as well as the 2 doors where the fine tailings are dropped from the filter presses into the 2 bays <br />immediately west of the chemical storage area. This concrete apron was approved as part of TR -05. <br />Revenue Mill Certification Page 15 of 20 <br />