Caving Methods - Estimation of Ore Reserves and Mining Methods in Alaska Juneau Mine (with Discussion)

The property of the Alaska Juneau Gold Mining Co., covering the Juneau gold belt for over a mile in length, consists of 136 claims and 24 mill sites; these are near Juneau, Alaska, in what is known as the Harris mining district. Gold was discovered in the district in 1880, by Richard T. Harris and Joseph Juneau, who had been prompted to explore the section by rumors they had heard among the Indians. Gold was first found on the beach at the mouth of Gold Creek and further search revealed the lode deposits in the Silver Bow basin, about two miles inland. The lode locations made immediately thereafter constitute the principal area of the Alaska Juneau group of claims. Gradually news of the strike spread and, during the late eighties, Silver Bow basin became a substantial producer of gold, both from placer work and from quartz milling. Numerous small mills of various types were erected to crush high-grade float and stringers gouged to shallow depths. Placer mining gradually ceased and the pioneer milling operations gave way to larger and better mills, which in time were the predecessors of the two large mills built by the Alaska Gastineau Co. and the Alaska Juneau Co. on the shores of Gastineau Channel. This evolution from arrastres to small mechanical mills, thence to the two large-capacity mills on Gastineau Channel, although a natural sequence of events, had a most important bearing on the development of the district. Knowledge of the character, extent, and value of the ore deposits gained by these early operations could not have been acquired otherwise. Spencer shows1 that the early mills were: Arrastres in 1881-82-83-84-85-86-88; a 5-stamp mill in 1882; a "newly devised grinding mill" in 1884; two Huntington mills in 1886; a 10-stamp mill in 1889; a revolving Dodge mill in 1890; a 5-stamp mill in 1891; and a 20-stamp mill in 1893. He also estimates the gold production to the end of 1893 as $1,000,000 from lode mining and $1,250,000 from placer mining. No estimate can