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<br />-9- <br />III. COMMENTS AND RECOMMENDATIONS <br />1. Two monitoring wells are completed in the Trout Creek Sandstone <br />(No. 5 Mine Well and Okie Plaza Well), which is the first regional <br />aquifer unit below the coal seams. During 1983, only water quality <br />information was reported at these locations. At this time, it does <br />not appear that the eastern portion of the No. 5 Mine is receiving <br />any significant inflows from any underlying units; therefore, <br />monitoring of water levels at the Okie Plaza Well (which is located <br />in the eastern portion of the mine) is not considered to be <br />important. However, based on information from the 1984 annual mine <br />inflow study (submitted to the Division on September 4, 1984), it <br />is possible that ground water from the Trout Creek Sandstone is <br />contributing to observed mine inflows in the west side of the No. 5 <br />Mine. Therefore, the Division concurs with Empire's commitment, as <br />stated in the mine inflow study report, to obtain quarterly water <br />level measurements from the No. 5 Mine Well. This monitoring <br />information should be included with other monitoring information <br />submitted in quarterly reports and in annual hydrologic reports. <br />2. Under Stipulation No. 5 of Empire's permit, summations of ground <br />water quality data are to be included in the annual hydrologic <br />reports. In order to address this, summary tables of ground water <br />quality data for each aquifer unit were generated for the data <br />collected in 1983, and for all data collected over the period of <br />record. While this method does have merit in enabling overall <br />evaluation and characterization of water quality data from each of <br />the aquifer units, it limits the ability to evaluate water quality <br />variations at each sample site. By averaging the data from several <br />sample sites completed in the same unit, any changes or developing <br />trends at an individual site may not be readily recognizable. <br />Also, if water quality at one particular site is significantly <br />different than that from other sites completed in the same unit (as <br />is the case with several of Empire's wells), this site, when <br />averaged with the other sites, will alter the mean values and <br />possibly make them less representative of actual overall water <br />quality for that unit. <br />In order to facilitate review and evaluation of the water quality <br />data, it is recommended that this data be listed by each individual <br />sample site and in chronological order in future annual hydrologic <br />reports. This can be done for both field and laboratory parameters <br />for both surface and ground water stations and should include all <br />historical records up through the current year of monitoring. An <br />example of this type of "master listing" of monitoring data for a <br />sample site from another mine's annual hydrologic report is <br />included for your review in Attachment A to this document. By <br />