<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>D. Kirk Nordstrom</dc:contributor>
  <dc:contributor>J. Michael Thompson</dc:contributor>
  <dc:creator>Charles N. Alpers</dc:creator>
  <dc:date>1993</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Time-series data on Zn/Cu weight ratios from portal effluent compositions [(Zn/Cu)&lt;/span&gt;&lt;sub&gt;water&lt;/sub&gt;&lt;span&gt;] at Iron Mountain, California, show seasonal variations that can be related to the precipitation and dissolution of melanterite [(Fe&lt;/span&gt;&lt;sup&gt;II&lt;/sup&gt;&lt;span&gt;,Zn,Cu)SO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;·7H&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;O]. Mine water and actively forming melanterite were collected from underground mine workings and chemically analyzed. The temperature-dependent solubility of Zn-Cu-bearing melanterite solid solutions was investigated by heating-cooling experiments using the mine water. Rapid kinetics of melanterite dissolution and precipitation facilitated reversed solubility experiments at 25°C. Non-reversed solubility data were obtained in the laboratory at 4° and 35°C and at ambient underground mine conditions (38° and 42°C). Copper is partitioned preferentially to zinc into melanterite solid solutions at all temperatures investigated. During the annual dry season, values of (Zn/Cu)&lt;/span&gt;&lt;sub&gt;water&lt;/sub&gt;&lt;span&gt;&amp;nbsp;in the Richmond portal effluent increase to values between 8 to 13, consistent with formation of melanterite during this period. During the annual wet season, the onset of high discharge from the mine portals is characterized by a significant decrease in (Zn/Cu)&lt;/span&gt;&lt;sub&gt;water&lt;/sub&gt;&lt;span&gt;&amp;nbsp;to values as low as 2. This phenomenon may be caused by dissolution of melanterite with values of (Zn/Cu)&lt;/span&gt;&lt;sub&gt;solid&lt;/sub&gt;&lt;span&gt;&amp;nbsp;ranging from 1.5 to 3.5.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1021/bk-1994-0550.ch022</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Chemistry Society</dc:publisher>
  <dc:title>Seasonal variations of Zn/Cu ratios in acid mine water from Iron Mountain, California</dc:title>
  <dc:type>chapter</dc:type>
</oai_dc:dc>