THE MINING AND QUARRY INDUSTRY I9IO 33 



tion, are too impure to be used for calcined plaster manufacture. 

 These features call for careful investigation before mining develop- 

 ments are undertaken in any new locality, but they need scarcely 

 be taken into account as fixing a limit upon the available supply in 

 general. 



IRON ORE 



Iron mining was quite active last year, in fact the industry made 

 a better showing on the whole than could have been anticipated 

 from the trend of the iron trade. A total of about 1,500,000 tons 

 of ore was hoisted from the mines, and the tonnage of furnace ore 

 produced was well above the quantity reported in any previous year 

 for a long time. The larger part of the shipments to furnaces con- 

 sisted of magnetic concentrates, averaging about 65 per cent iron. 



At the opening of the year the iron market showed a good deal 

 of activity and seemed to foreshadow a prosperous season for 

 mining. It began to weaken, however, after the first month or two 

 and then as the season advanced fell off rapidly until prices were 

 on a very low basis. The year closed without any immediate im- 

 provement in prospect. The effect of the slump was to discourage 

 new enterprises and in some degree to curtail operations on the part 

 of the active mines. A few companies ceased work altogether 

 before the year ended. That the output held up so well in spite 

 of the unfavorable market situation may be attributed probably to 

 the sales of ore under contracts which served to keep most of the 

 mines busy during the dull months. 



In the Adirondacks exploratory work was carried on much as 

 usual and the record of results compared well with that of any recent 

 year. Promising developments were reported from the vicinity of 

 Arnold hill, of which an account is given on a subsequent page. The 

 Mineville-Port Henry district also received attention. 



The accompanying table gives the statistics of production of the 

 different classes of ores for the last two decades. The figures are 

 based on the shipments of lump ore and concentrates to furnaces 

 rather than the mine output. The volumes of the Mineral Resources 

 published by the United States Geological Survey have supplied 

 the data for the years previous to 1904. 



