From abstract: To help the mining industry of Alaska and to assist in the development of the mineral resources of the Territory have been the prime motives of the Geological Survey's investigations in Alaska during the past 35 years, in which nearly one half of the Territory has been covered by its reconnaissance and exploratory surveys. It was natural, therefore, that the Alaska Railroad, when it undertook intensive consideration of the problem of finding tonnage that would increase its revenues, should look to the Geological Survey to supply technical information as to the known mineral deposits along its route and to indicate what might be done to stimulate a larger production of minerals and induce further mining developments and prospecting that would utilize its service.

From abstract: The Girdwood district has been known for about 35 years to contain placer gold, but the source of the gold in veins was not discovered until about 1909. When the Alaska Railroad was completed through Girdwood it was hoped that the improved transportation facilities would enable the lode mines to operate at a profit and also to furnish tonnage to the railroad. Production from the quartz veins, however, has been negligible, although one placer mine has been operating steadily for several years.

From abstract: The gold quartz veins of the Willow Creek district belong to the type of ore deposits that may be expected to continue downward for several thousand feet below the present surface. The veins occur in an essentially homogeneous quartz diorite intrusive mass, batholithic in form ; therefore, the composition of the wall rock plays practically no significant part in the distribution of gold within the veins. The veins were formed partly as fissure fillings and partly by replacement of the wall rock along fractures and of fragments of wall rock caught between the fracture walls. Structurally the deposits are essentially composite lodes, although quartz lenses of considerable size have also been formed.

From abstract: The Mount Eielson district lies in south-central Alaska, on the north side of the Alaska Range, about 30 miles east of Mount McKinley. The most widely distributed rocks of the district include a thick series of thin-bedded limestone, calcareous shale, and graywacke of Paleozoic, probably Devonian, age. These sediments are cut by a mass of granodiorite which forms most of Mount Eielson and which was intruded probably in late Mesozoic time. The intrusive has sent a multitude of dikes and sills into the associated sediments.

From abstract: The area in the vicinity of the West Fork of the Chulitna River, Alaska, one of those examined in 1931 in connection with the study of mineral resources in districts tributary to the Alaska Railroad, contains numerous prospects but, as yet, no productive mines. Its placer deposits are negligible but some of its lodes may prove valuable for gold and silver and perhaps also for copper and arsenic.

From abstract: The Valdez Creek mining district was one of those visited in 1931 in connection with the study of the mineral resource of the region tributary to the Alaska Railroad. It is underlain by argillite, schist, tuff, tuffaceous conglomerate, limestone, and greenstone, listed in approximate stratigraphic order beginning with the youngest.

"To the end of 1930 Alaska, according to the records of the Geological Survey, had produced placer gold to the value of $258,962,000 from mines widely scattered throughout its length and breadth. The distribution of the placers from which the gold was recovered has been stated in more or less detail in the annual summaries published by the Geological Survey on the mineral industry of Alaska and also in its more complete reports on many of the individual mining districts. Although these summaries and reports have furnished information regarding the larger regions, they have not always given specific details regarding the smaller districts. Furthermore, there has been no recent attempt to assemble and publish in one place the scattered statistics regarding the placer-gold production by years and by regions and districts. The purpose of the present report is to set forth in condensed but comprehensive form a summary of the placer-gold production of Alaska so far as it can be determined from the available official records."

This report provides and in-depth description of the Moose Pass-Hope District in Alaska, including on overview of the general area, physical geology, and economic geology.

From abstract: The Kantishna mining district is about 90 miles west of McKinley Park station on the Alaska Railroad. The part of the district covered by this report comprises an area of about 72 square miles in the form of a strip 6 miles wide and 13 miles long. The bedrock is mainly a metamorphic series of rocks which within the area has been differentiated into a quartz-muscovite schist and a calcareous faces that ranges from limestone to chlorite schist. A few small dikes of quartz porphyry and diabase intrude the schist. The general structure trends N. 700 E., and from an axis that extends from Eldorado Creek northeastward to Spruce Peak the schistosity dips to the northwest and southeast. It is along this axis that the heaviest mineralization has occurred.