The City has contracted with Carlton Engineering to assist the City with the environmental due diligence review of the property. This included the review of several thousand documents, as well as, several site visits and analysis. During this process the Tailings Dam, which is located on the south eastern portion of the property, became an important historical find and noteworthy aspect of the property. According to the primary engineer working on the project Mark Montgomery, the tailings dam is a “unique historic structure.” Montgomery said, “The Senior Structural Engineer (of Carlton Engineering) got really excited about it.” He explained that most dams that were constructed during the same period, around 1914 when the Oro De Amador Dam was constructed, were built like a pyramid and water at the bottom tapered up to the top. The dam located on the Oro de Amador property, is unusual and unique for a dam of that time period because it stands at approximately 60 feet high and 600 feet long and incorporates concrete arches and half circles in its design. Montgomery said the dam is “unique in its style of construction,” and that he has only seen one other structure in his career that was similar and that dam can be found on the Argonaut Mine property. He said the dam found on the Argonaut Mine property is similar but yet different than the distinctive find on the Oro de Amador property. Montgomery said the find “is a really neat structure…(and) I’ve never seen one like it before.” However, the rare structure is deteriorating after years of exposure to the natural elements. Montgomery specifically mentioned the right side of the dam is weakening and there are also indications of vegetation intrusion which could be leading to further corrosion of the concrete used to build the dam. Also of concern is a hole, that appears to be man made, that was punched into the dam. “You ask, ‘why would somebody want to do something like that?’” said Montgomery. He went on to explain that the State regulates dams that are over 6 feet high.  “It seems very suspicious that a hole was punched into that Dam at approximately 5 feet making it so the dam does not have to be regulated by the State Department of Dam Safety.” Nevertheless, Montgomery made it clear that the City has many attractive options pertaining to how they would like to preserve the structure. Two options mentioned included filling the lake bed behind the dam and making a permanent lake bed, or the City could defer drainage around the dam and “basically turn it into a historic piece of yard art.” Montgomery did point out, however, that any increase in impounded water such as a permanent lake bed, may require structural improvements to the dam iteself. Montgomery stated that “Bottom line- if the dam stays the way it is, it could hold for 100 years to 200 years with out failing, (but) it could fail tomorrow” and that is why he explained that maintaining the integrity of the dam should be explored. No matter what the City decides to do with the dam- one fact does still remain, and that is that the Dam is historically significant and of particular interest to one local Society, the Historical Society. Amador Co. Historical Society President and also Current Jackson Planning Commissioner Dave Butow said the dam is of great interest to the Historical Society. Butow explained that the Society would like to include the dam when they do an inventory of historically significant structures or areas in the county. “(The dam) and many other structures in this city will be eligible for national registry,” said Butow thus creating another unique historic attraction for Amador County.