<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>2111100 - Disclosure - Gold Stream Arrangement</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>D2013Q2YTD</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0001415020</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>tc_GoldStreamArrangementAbstract</ElementName><ElementPrefix>tc_</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Gold Stream Arrangement [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>tc_GoldStreamArrangementTextBlock</ElementName><ElementPrefix>tc_</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>terseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="D2013Q2YTD" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div style="font-family:Times New Roman;font-size:10pt;"&gt;&lt;div style="line-height:120%;padding-bottom:10px;padding-top:10px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Gold Stream Arrangement&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:10px;padding-top:10px;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Pursuant to an agreement dated October 2010, as subsequently amended in December 2011 and August 2012, with a subsidiary of Royal Gold, Inc. ("Royal Gold") (referred to as the "Gold Stream Arrangement"), TCM agreed to sell Royal Gold &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;52.25%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; of the refined gold production from Mt. Milligan for a total upfront payment of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$781.5 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; plus &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$435&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per ounce, or the prevailing market rate if lower than &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$435&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per ounce, when the gold is delivered. Pursuant to this Gold Stream Arrangement, through &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, TCM has received total cash payments of &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;$768.6 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; from Royal Gold, comprised of a payment of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$37.0 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; on June&amp;#160;1, 2013, &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$62.0 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; on March&amp;#160;4, 2013, and payments of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$305.0 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; in 2012, &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;$138.1 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; in 2011 and &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;$226.5 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; in 2010. The final scheduled payment of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$12.9 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; by Royal Gold is scheduled to be paid on September&amp;#160;1, 2013.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:10px;padding-top:10px;text-align:left;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;TCM must maintain a deposit record during the term of the Gold Stream Arrangement wherein TCM reduces the &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;$781.5 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; paid by Royal Gold by the difference between the current market price, if higher than &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;$435&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per ounce at the time of sale of refined gold to Royal Gold, and &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;$435&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per ounce, multiplied by the amount of refined gold sold in such sale. If, at the end of the initial &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;50&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;-year term of the agreement, the total deposit amount reflected in the deposit record has not been reduced to nil, TCM must pay to Royal Gold the remaining balance reflected in the deposit record.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:10px;padding-top:10px;text-align:left;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Royal Gold has a security interest in all of the Mt. Milligan assets until its total deposit amount has been reduced to nil. Royal Gold's security interest is subject to subordination to project or corporate financings by TCM, except that, in such circumstances, Royal Gold retains a first priority interest in &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;52.25%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; of the refined gold from Mt. Milligan. The agreement with Royal Gold also restricts TCM's ability to incur debt in excess of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$350 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; that is secured by the Mt. Milligan assets until the earlier of the date upon which &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;425,000&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; ounces of refined gold have been sold and delivered to Royal Gold pursuant to the agreement or the date upon which the aggregate dollar amount of the difference between the market price for the gold delivered to Royal Gold under the agreement and the price actually paid by Royal Gold pursuant to the terms of the agreement exceeds &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$280 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;. After the total deposit amount has been reduced to nil, Royal Gold's security will consist solely of its first priority interest in &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;"&gt;52.25%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; of the refined gold. The cash payments received under the Gold Stream Arrangement are recorded as deferred revenue and classified as a long-term liability in TCM's Condensed Consolidated Balance Sheets. Once Mt. Milligan is in production and begins delivering gold to Royal Gold, the liability will be amortized over the life of the mine based on the amount of gold delivered.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:10px;padding-top:10px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In the event of any default under the Gold Stream Arrangement, Royal Gold could require TCM to repay the deposits received from Royal Gold, which amounts totaled &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$768.6 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; as of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;.&lt;/font&gt;&lt;/div&gt;&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>This element represents details of the purchase and sale agreement for the sale of payable gold related to the Company's Mt. 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