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The story of the development of Steep Rock Iron Mines is a compelling read because of its scale and audacity in the face of the rugged, almost impenetrable wilderness in which the participants had to work. The story includes
To get the best idea of what it was really like, you need to sit down with a retired miner and have him or her spin out their tales of close calls, of pratical jokes, of the daily grind. The best online alternative is presented below. The Project Description includes a lot of facts, with little reference to the bitter winters through which the dredging continued unabated, or the miserable heat and biting bugs of the summer. It does not make mention either of the exceptional fishing opportunities at the time. You can also check out the Timeline for a chronological outline of the major activities in the development of the mines. More History also provides details about the economic impact of the Steep Rock Iron Mines development. Here is a Project Description written at the time (ca. 1951) by an anonymous author. I have found it to be one of the most readable description of the project that I have come across. Steep Rock Iron Mines Ltd – Project Description – [1951 ?] – Diversion of Steep Rock Lake — In order to make large quantities of ore available for open-pit mining, and to facilitate subsequent underground mining operations, it was necessary to divert all but the West Arm of Steep Rock Lake. Intensive study was devoted to the problem, since the course of the Seine River had to be altered, and the elevations of Steep Rock and several other lakes had to be changed. Investigations of five alternate routes proved that the plan to divert the Seine River from Marmion Lake, through Raft and Finlayson Lakes into the West Arm of Steep Rock Lake, was the most feasible. Procedures Pre-war estimates by various competent engineers had indicated that it would require from three to six years to complete the work necessary prior to the initiation of open-pit mining operations on the "B" ore zone. However, means were found materially to expedite this programme. Under the accelerated schedules, roads to the various construction sites were built during the first quarter of 1943, and despite difficult wartime conditions, the diversion was completed and sufficient water removed from Steep Rock Lake to permit mechanical and hydraulic stripping operations and some incidental mining on the "B" ore zone through the summer and fall of 1944. Full-scale mining operations began in May 1945, exactly 24 months after the commencement of the diversion work. In general, the diversion required the removal of a major waterway to a new route some four miles northwest of its original location, and embodied a diversity of construction jobs within an area of about 100 sq. mi. Many of these projects were carried out simultaneously and required most careful synchronization. The work included:
These and myriad incidental jobs constituted the diversion, which was completed during 1943. During the last six months of 1943, the Ontario Hydro-Electric Power Commission extended their high-tension lines from Port Arthur to the property (a distance of 130 miles). This well-built permanent line has ample capacity for our large-scale power requirements. During the ensuing year, 1944, the following work was carried out:
At some future date, if – as is considered likely, ore deposits are also found to exist in the West Arm of Steep Rock Lake, they too may be accessible to open-pit and underground mining operations by dewatering the West Arm of the Lake. The complete diversion plan makes provision for this eventuality by extending the present diversion to the Southwest through Barr, Reed and Modred Lakes to the Lower Seine River. Dewatering Steep Rock Lake Although the dewatering of Steep Rock Lake was recognized to be one of the largest pumping projects ever undertaken, investigation proved it to be entirely feasible and economically sound. The Middle and East Arms of Steep Rock Lake (the section to be dewatered) were estimated to contain over 118 billion U.S. gallons of water, of which some 70 billion U.S. gallons, plus an estimated annual inflow from rainfall of 5 billion gallons per annum, would have to be removed prior to the commencement of mining operations on the "B" ore zone. Accordingly, the necessary major pumping plant was assembled , and the equipment selected was designed to provide the maximum mobility and flexible operating characteristics. The pumping plant had a total capacity in excess of the aggregate of those used to supply water to the fourteen largest Canadian cities. Pumping The execution of this programme required the construction of the high-tension lines referred to above, to supply power for the pumps and ultimately for mining operations. The Company then had to erect seven miles of 44,000 volt main feeder-line with subsidiary tap-offs from the Steep Rock terminus of the Hydro line to the main plant and pumping station. During this time, seven steel-barge hulls were fabricated and two 24" pumping units installed on each barge. Before the barges could be set in place, a pumping forebay had to be excavated, and an 8' x 12' tunnel, 300' long, driven through the solid rock of Narrows Island. This tunnel led from the pumping forebay to the West Arm of Steep Rock Lake. The barges were finally assembled in position, the discharge pipes connected to the forebay, and the first pumps put into operation on December 15, 1943. Between December 15, 1943 and May 9, 1944, the productive portion of the lake east of the coffer-dams was lowered 80 feet, at the rate of .5 feet per day. By this time the water level had been lowered sufficiently to reveal the Mosher Point bar, which then divided the remaining water into two separate lakes. Following this division, the capacity of the fourteen pumps was more than necessary to maintain the scheduled lowering of Middle Arm Lake, and four pumps were therefore moved into East Arm Lake to continue the lowering of the latter, and at the same time, to provide high-pressure water for the hydraulic stripping of the "B" ore zone. The remaining pumps had sufficient capacity to continue lowering Middle Arm Lake at a pre-determined rate. With the exception of one major move referred to above, only 3% of the total possible pumping time was lost through delays due to moving, repairs, power failures, or other causes. By November 1944, the rapid production in area which accompanied the lowering of the water level of Middle Arm Lake caused a surplus of pump capacity at the Narrows Island pumping station. Consequently, in December, four more pumps were moved to provide additional water to assist in the hydraulic stripping. In November 1945, the Narrows Island pumping station was moved southward to a more favourable and permanent location, to facilitate the handling of the slurry from hydraulic operations on the "B" ore zone. The Midwest Arm is now almost completely dewatered. East Arm Lake is being steadily lowered by the six pumps which are supplying water to the "B"ore zone. Development After the bulk of the water had been removed from the Lake and the "B" ore zone exposed, the removal of the heavy overburden, including clay-silt, boulder clay, and rock, commenced. This marked the culmination of the diversion and pumping operations, which are not normally encountered in the development of open-pit mines. Hydraulic Stripping The depth of silt overlying the part to be mined first varied from a few feet to a maximum of 100 feet and many suggestions regarding the most feasible method of removal were put forward by a number of authorities. Each had its advantages and disadvantages. All minds agreed that the clayey nature of the material precluded the use of standard mechanical excavating equipment, and it was decided to disintegrate the overburden using high-pressure hydraulic jets and to pump the slurry by means of suction dredges to disposal points in Middle Arm Lake. Hydraulic stripping operations were commenced in June 1944, and have been carried out continuously since that time. To March 31, 1951, a total of 14,257,273 cu yds of silt have been removed by this method. Mechanical Stripping Early in July 1944, sufficient silt had been removed hydraulically from the "B" ore zone to allow power shovels to commence stripping the gravel, boulder clay and rock from the footwall area. Shortly after, that portion of the ore haulage road which had to be constructed across the lake bottom was completed, finally connecting the open pit with the crusher. Mechanical stripping methods have since been the means of removing 10,892,312 cu yds of waste material up to March 31, 1951. Mining The ore occurs in wide steeply dipping vein deposits and is mined at present by quarrying methods with heavy mechanical equipment. After drilling with 9 inch electric churn drills, the ore is blasted and then loaded by large diesel and electric shovels into diesel powered 22 ton ore trucks. From the pit the trucks convey the ore some 4,000 feet to the loading terminal. Subsequent to incidental mining operations late in 1944, full scale open-pit mining has proceeded continuously during the period of lake navigation since 1945 (winter operations are confined to the removal of waster material from the walls of the ore body)..Total production by seasons to date is as follows:
Preparation and Shipping A crushing and screening plant was erected at the terminus of the Canadian National Railways spur line from Atikokan. Construction of the plant commenced in June 1944, and the first railway shipments were made to ore docks at Superior, WI at the beginning of October, 1944. The function of this crushing and screening plan is to segregate the one premium lump grade from the ore as mined: The Steep Rock grade is an open-hearth lump ore containing pieces 4" to 10" in size; the Seine River grade consists of finer material, each particle not exceeding 2" in size. At one time the pieces between 2" and 4" were sold as a separate grade. These are still screened out but are now sold either as Steep Rock or Seine River grade, depending on their quality. The plant equipment is relatively simple, consisting of a surge bin, a feeder, a large jaw crusher, conveyor belts, double-deck sizing screens, and ore storage bins from which the railroad cars are loaded. In addition to the above mentioned two grades of ore, a third grade known as Freeborn is also being shipped. This grade is a sintering ore which is crushed and screened to minus ½" at the stockpiles by a portable crushing and screening plant. At present, the Canadian National Railways has six hundred system-owned cars. Construction of additional cars will be necessary with the development of the "A" orebody, or the Hogarth Mine as it will be known. The Canadian National Railways provided a service spur from Atikokan, a divisional point in their line from Winnipeg to Port Arthur, to the site of our crushing and loading terminal. In addition, with the co-operation of the Dominion Government, the railway constructed an ore dock at Port Arthur having a storage capacity of 30,000 tons of ore. The structure was partially completed and a portion ready for use during the latter part of the 1945 shipping season, and was finished for the opening of navigation, 1946. Further Development of the Steep Rock Iron Mine The "B" ore body which has been initially developed as an open pit is now known as the Errington Mine. Steps are now being taken to convert this from an open pit operation to an underground mine. A large shaft complete with the most modern facilities is now being sunk on Float Ore Island approximately 1,800 feet south of the Errington orebody. It is expected production from this shaft will commence late in 1952. To the northwest of the Errington Mine is the "A" orebody of the Hogarth Mine as it is now known. Approximately 35,000,000 cu yds of clay silt must be removed from this orebody before mining operations can commence and an additional 15,000,000 cu yds to compete the clay stripping. To accomplish this task, one of the largest electric dredges in the world is now stripping this material at the rate of 1,500,000 cu yds a month. This dredge, the "Steep Rock", has a hull 133 feet long and 40 feet wide and weighs approximately 900 tons. It took 39 railway cars to transport the dredge from Boston harbor to Steep Rock. Construction Aggregates Corporation of Chicago have the contract for this project. To the northeast of the Errington Mine in Fall Bay is the "C" orebody which is under option to Inland Steel Company. During the last two winters they have conducted a very vigorous drilling campaign and the development of this ore zone into a producing mine can be expected in the next few years. To the south of the "C" orebody another ore zone is under option to a group of iron and steel companies headed by Pickands-Mather. Drilling of this area will be started in the very near future. Several other ore zones which can be considered as potential mines are also known and in the years to come further exploratory and development work will no doubt result in the addition of other mines to the growing Steep Rock range. Fishing Exploits from the Steep Rock Echo Results of the Annual Fishing Competition at SRIM
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