144 THE MINERAL llESOURCES OF PRINCE GEORGe's COUNTY 



running from 40% to 45% of metallic iron. Phosphorus and sulphur 

 are unusually low, while manganese and silica are high. In one 

 place a deposit of manganese ore has been found associated with the 

 iron ore. 



The ore is mined in a very primitive manner, all the labor being 

 done by hand, and the ore hauled direct to the furnace. The usual 

 method of working is by open pits, but in some cases the ore is 

 removed through slope tunnels and shallow shafts, where the cover- 

 ing of barren clay is too thick to be profitably removed. In the tun- 

 nels and shafts very little timbering is required. Practically no 

 capital is necessary for this kind of mining and most of the men 

 engaged in the operations are lessees who pay a royalty of about 35 

 cents per ton to the OA\mer of the land. In most places the operators 

 are able to make fair -wages, but no extensive mining can be done 

 under these conditions. When the overburden becomes great the 

 mine is abandoned and new openings made, so that it is not advisable 

 to represent the working mines on the map. It is sufficient to say 

 that they are all within a few miles of Muirkirk and Contee. At the 

 furnace the ore is first roasted in order to eliminate any sulphur and 

 also to convert the carbonate ore to the form of oxides. 



The pig iron produced at Muirkirk has long been known for its 

 tensile strength, and for this reason commands a higher price than 

 any other pig iron manufactured in this country. There is a ready 

 market for the product, which is used exclusively in the manufacture 

 of special articles in which great strength is required. It has been 

 used extensively by the United States government in the manufac- 

 ture of cannon and is also in demand for car Avheels, cylinders and 

 various special kinds of steel. The claim is made hj the proprietors 

 of the furnace that their product is the strongest pig iron produced 

 in the United States. The slag has been used as road metal in the 

 vicinity of Muirkirk, and at the present time is being shipped else- 

 where for this purpose. 



THE petroleum AND NATURAL GAS. 



Rumors have been circulated at various times of the discovery of 

 petroleum and natural gas at several different places within the 



