17 The lease shall provide that any person who has recorded a claim under the Northwest Territories Placer Mining Regulations shall be entitled to run tailings into the river at any point thereof and to construct all works which may be necessary for properly operating his claim, but no such person shall construct a dam or wing-dam within 1,000 feet from the place where any dredge is being operated, or obstruct or interfere in any way with the operation of any dredge.
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