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32 TAE MarRINE REVIEW DIFFICULT PROBLEM SPLENDIDLY HANDLED Although the record breaking per- formances of the Duluth, Missabe & Northern railroad in hauling ore from the Mesabi range to the Duluth docks have excited attention and admiration because of the tonnage handled, the real significance of the accomplishment is little recognized because the real problem is little known. This carrier has a railroad problem entirely its own, a problem in which not only the railroad itself is interested but which concerns the vessel interests whose boats load at the Missabe docks and 'the furnace interests which use this ore. It is a unique problem with the Missabe road, not because. the Great Northern and Duluth & Iron Range railroads never have to meet it, but because the mixing of the ore from the mines whose output the Missabe road handles, is a continuous operation and involves practically ev- ery car of ore shipped. - To illustrate concisely the extent to which this consideration enters in of so. mixing the various ores from the different mines, that from the time the ore leaves the range till it is emptied into the dock, only 80 miles away, | the ore from all the hundred or so shovels and numerous. shafts _-- shall have been classified into but five groups of guaranteed analysis from which analyses a variation of not more than a fraction of a per cent is allowed, the guarantee covering not only iron, but also phoshorus, silica and manganese, the following state- ment avails in a measure. There was shipped up to July 1 from the Duluth docks approximately 4,100,000 tons or allowing an average of 2,500 tons to the train, the contents of 1,640 trains. This' is a conservative number: of trains but something of the situation may be realized when of all that number scarcely a dozen trains have contained ore of such analysis as to pernfit of being run straight from the mines -to the docks without being broken up fon mixing. In. the last month an average daily tonnage of over 80,000 has been shipped, practi- cally all of which had to be-manipu- lated. _ The handling of the major portion of this-mixing is directed from. the office of the Oliver Iron Mining Co. at Hibbing. The considerations gov- erning are hard and. fast limitations. The railroad. and mining must not be delayed, every cargo must meet one of five guaranteed analyses, and each boat to be loaded must have .of ore. operations train report confirming the car num- for a certain draught so many tons That all these requirements can be met continuously with absolute pre- cision is readily seen to be impossi- ble and because they cannot be is 'why the mines complain of lack of empties, the boats complain of de- lays and slow loading at the Duluth docks, and the furnaces complain that the ore they have received is off grade. A certain amount of complaint is probably necessary or at least ex- pedient in keeping the wheels going at the present strenuous pace and in obtaining the best results possible but it is also to be remembered that the ore is as it is, and pig iron must be made from the ore as it is and not as we wish it might be. To .begin. with the operator at Hib- bing receives from the dock a 24-- hour notice of the boats due to ar- rive in the next 24 hours, and the group or kind of ore they are com- ing after. This gives him an idea of _the tonnage of the boats he has to fill and he begins to lay out or per- haps better build up in the dock what are called "blocks" of ore:each block- The dock agent various blocks not- ing the 'pockets in which they lie -and so far as possible the blocks are not split up and put in separated portions of the dock. The boat cargoes are then made up of these blocks, a typi- cal order for loading being, "load the Smith with block No: 307". or "load with blocks Nos. 570 and 502" or per- haps "load the Brown with block 387 and 500 tons 'of block No. 185." It is evident then that these blocks must have been so prepared that when loaded into the boat they constitute a having a number. keeps track of the cargo of the correct average analysis: and of the given tonnage. This*can be made the more clear by turning to the work of the Hib- bing office. When the loaded ore cars are hauled from the mine or shaft pocket to the mine siding a sample is taken from each ten cars-and when a train is made up .and started down toward Duluth the sample with the numbers of the cars from which it is taken is sent to the laboratory for analysis which analysis is then re- ported to the operating office at Hib- bing. When the train reaches Kee- nan, a short distance down the road, the conductor telegraphs baek his bers. A "train sheet" is then made out and the analysis placed opposite the groups of ten cars making up the é train of from forty to fifty cars, From the analyses the tonnage of ore shipped is estimated and the separa- tion into blocks is begun. 3 The principal distinction is of course between Bessemer and_ non- Bessemer. ores, but it is also main- tained with regard to iron, silica and manganese and the five groups are designed to cover, these variations. Therefore, wherever the several parts of the train load are sufficiently dif- ferent from each other in analysis to approach in character one group. 'rather than another they are given a 'block number. That ore also which may be half way betwen two groups will be disposed in the same way. The ore left 'in the dock must also be renumbered and oftentimes the en- tire train is added to blocks already started in the dock, the added ore if both are off . grade, being tsed to raise or, lower the average analysis of the block. Bach. ~ cargo -is considered as containing so many units of each element, the number of units de- pending on the. group «and the tonnage. Therefore, in building the blocks, the thumber of units' each contains is first figured from _ the estimated weight while the train is enroute. When the train reaches Proctor: and. is -actually weighed a correction is made and the. necessary units added or subtracted, and as a result a certain block may have to be changed from one boat to another. As soon as the operator at Hibbing has the train "blocked out" he telegraphs to the transfer yards at Proctor his orders and the various blocks of ore are switched. out and new trains made so that the ore can be dumped on the. proper dock and proper place without any switching on the dock. It is evident that the blocks must be as varied in size as the boats are in tonnage. No block must be allowed to run: so far "off. grade" in: taking care of the ore coming down as to make it impossible of neutralizing without adding more ore than any boat would hold.. There must also be provided what are called "balance blocks" which analyze "on grade" and with which a cargo almost completed may be finished: where the blocks have not. been quite sufficient. It is also evident that in every case the entire block must be taken by the boat since it is only the average analysis which meets the group requirements