Inspiration Consolidated Copper Company operates an open pit mine, concentrator, oxide ore leach plant, smelter, and tank house for the production of cathode copper near Inspiration, Arizona. an Inspection to acquire data with which to evaluate the design and operation of existing particulate matter pollution control equipment at the smelter and to survey the suitability of the smelter to be emission tested was conducted by state and EPA personnel on January 26-27, 1976. Substantial amounts of process, control equipment, and stack sampling were requested of and received from the Company. The following conclusions are based on the inspection and a review of the information obtained: 1. The Inspiration Smelter is the newest Arizona smelter and the only one which has an electric furnace instead of reverberatory furnaces. It is also one of the two smelters which reports, on the basis of stack testing results, that it is in compliance with the process weight regulation. However, as will be discussed below, those stack test results should be considered invalid. 2. This smelter uses cyclones as a pretreatment device preceding the electrostatic precipitators (ESP's). This arrangement reduces by 80% the particulate matter concentrations to be controlled by the ESP's. No test data are available with which to draw conclusions as to the appropriateness of such a control system. 3. The measured gas volumes produced by the individual process units are less than the design gas volume capacities of the control systems. This allows the control systems to operate at their design efficiencies. 4. The source tests conducted at the Inspiration Smelter did not determine whether the smelter was in compliance with the process weight regulation because both tests were performed at an unsuitable location. Upstream and downstream flow disturbances are in close proximity to the sampling station so that Method 1 criteria cannot be met. In addition, only one diameter could be traversed and only 12 points, instead of 48, were sampled. Isokinetic rates were not within tolerances. 5. The control system design of the entire smelter suggests the smelter is capable of complying with the process weight regulation. Continued performance of an acid plant requires a nearly particulate free inlet gas stream. Thus, the cyclones, ESP's, and cold gas cleaning system of scrubbers and mist ESP's must perform adequately and continuously. If the inlet particulate matter concentration to the acid plant is high, the catalyst beds in the acid plant conversion towers will soon clog, the plant will be shut down, and the bypass stack will have to be used.