The discovery of a deposit containing copper, gold and other minerals in Rouyn-Noranda, in northwestern Quebec, started a mining rush that spurred the economic development of what was then a remote area of the province.

The initial mineral discovery that led to the development of the Horne mine was made by Edmund Horne—the mine’s namesake. Following prospecting trips to the area in 1911, 1914 and 1917, he staked his first claim in the area during the summer of 1920.

“Horne managed to raise $225 from 10 individuals and the Tremoy Lake Prospecting Syndicate was formed,” wrote Harold L. Gibson, David J. Kerr and Sergio Cattalani (Explor. Mining Geol., Vol. 9, No. 2, 2000). “With this ‘grubstake,’ Horne ventured again to Lake Osisko and staked 70 acres, not realizing at that time that his first claim would ultimately contain about 95 per cent of all the ore exploited from the Horne mine.”

Noranda Mines Limited was incorporated in May 1922 to exploit the Horne deposit; Oliver Hall recorded that “Noranda” is an abbreviation of “Northern Canada” (CIM Bulletin, 1937).

News of Horne’s success drew large numbers of prospectors into the area in the early 1920s. “During the twelve months beginning with July 1924, as many as 5,143 mining claims were recorded,” wrote A.O. Dufresne (CIM Bulletin, 1926).

Gibson et al (2000) noted: “It is important to remember that prospecting in northern Quebec during these early years was incredibly difficult with no existing access except canoe routes, and in most respects, was more challenging and costly than exploration in the remote areas of today.”

In May 1924, the Montreal-based Laurentide Air Service began regular hydroplane flights from Angliers, Quebec, and Haileybury, Ontario, to the Rouyn mining camps. “The commencement of this service to the Quebec gold-fields is notable, as it is the first time that a regular commercial aeroplane service for a mining district has been initiated anywhere in the world,” pointed out G.C. MacKenzie (CIM Bulletin, 1924).

A few years later, C.P. Browning (CIM Bulletin, 1927) added, “The transportation facilities have been greatly bettered by the construction of a branch line from O’Brien, on the main transcontinental line of the Canadian National Railway, into the Rouyn area.”

A.O. Dufresne (CIM Bulletin, 1928) noted that two towns had been created in the area of the mining camps. “Alongside the pioneer town of Rouyn is the company town of Noranda. Both were incorporated by Acts of the Provincial legislature in 1926,” he wrote. “The town of Rouyn, on the west shore of a pretty lake, has grown in less than three years out of the virgin forest. In July 1926, it boasted 250 to 300 buildings of all sorts and had a population of 1,500; in December 1927, the number of buildings was fully 700 and the population 4,500, and growth still continues apace. The townsite of Noranda, immediately to the north of the town of Rouyn, is rapidly rising along the lines of the most modern town-planning principles.”

Rouyn and Noranda went on to merge in 1986, becoming the city of Rouyn-Noranda.

The Horne mine

Meanwhile, the development of the Horne deposit continued. Noranda Mines made a production decision in 1925 based on reserves of 611,500 tons grading 0.27 g/t Au and 5.66 per cent Cu, according to Gibson et al (2000).

“Work on the Horne property has been pushed with great rapidity,” wrote H.C. Cooke (CIM Bulletin, 1926). “The No. 1 shaft was sunk to 328 feet and stations cut at the 206 and 306-foot levels. More than 4000 feet of lateral work was done. The No. 2 shaft is sunk to a depth of 158 feet, and more than 800 feet of lateral work done at the first or 140-foot level.”

Noranda Mines began constructing a smelter in June 1926, and commercial production at the Horne mine began in late 1927. “The first copper ingot was cast on December 17th, 1927,” wrote Dufresne (1928). “The product shipped is copper in slabs, 99 percent pure, carrying some four ounces of gold and twelve ounces of silver per ton.”

However, it was not immediately clear how valuable the Horne deposit would turn out to be. “Construction of a smelter was an economic gamble, given the relatively limited ore reserves at this stage; however, it paid off handsomely in the years to come when the Horne deposit proved to be much larger than initially projected,” wrote Gibson et al (2000).

The sinking of a third shaft at the Horne mine began in 1926, which led to an important discovery in 1928. “The No. 3 shaft entered a swelling of the H ore-body and was found to be in sulfide with high copper and gold values,” wrote Hall (1937).

The bulk of the mine’s subsequent production came from two massive pyrrhotite-pyrite-chalcopyrite pods, designated the “Upper H” and “Lower H” ore bodies, that were located within the upper 950 metres of the mine workings and fell entirely within Edmund Horne’s original mineral claim from 1920. “Together, the H ore bodies yielded over 90 per cent of the Horne mine production,” wrote Gibson et al (2000).

Custom smelter

The Horne mine remained in continuous production until July 1976. “Since the closure of the mine in 1976, [the Horne smelter] has been operating as a custom smelter,” wrote C.H. Teh and L. Lamothe (CIM Bulletin, 1985). “The concentrates treated at the smelter come from various mines with mixed sulfide ores, many of them containing significant amounts of lead and zinc.”

The Horne smelter underwent several technological changes since its original construction in 1927. In March 1973, it pioneered a prototype continuous process furnace. “The Noranda Process is a continuous operation in which the smelting and converting steps of the traditional reverberatory furnace and converter can be combined in a single, cylindrical, refractory-lined reactor,” wrote J.B.W. Bailey and A.G. Storey (CIM Bulletin, 1980).

“The Noranda continuous smelting process has been in operation for six years and in that time it has smelted a million and a half tons of concentrate. It is currently smelting 1,200 to 1,250 tons per day of concentrate on an instantaneous basis and it is handling approximately 40 per cent of the Horne smelter throughput. Since early in 1975, a high-grade matte averaging 73 per cent copper has been produced, which is then sent to the converter aisle for final treatment.”

A later phase of production at the Horne mine, called REMnant NORanda (REMNOR), began in February 1985 to provide auriferous flux to the smelter from the mine’s upper levels. “REMNOR operations ceased in early August 1989, after producing approximately 604,000 tonnes averaging 5.8 g/t Au, including 118,000 tonnes of massive sulfide ore grading 7.2 g/t Au,” wrote David J. Kerr and Robert Mason (CIM Bulletin, 1990).

They noted that in total, from 1927 to 1989, the Horne mine “produced 53.7 Mt of ore grading 6.1 g/t Au and 2.2 per cent Cu.”

The Noranda Converter (CvN) was developed in 1997 to replace the four conventional Pierce-Smith converters that had previously been used at the smelter. “Developing and implementing the CvN were major steps forward in maintaining Horne smelter’s competitive position in the custom smelter market, while improving operational flexibility and environmental performance,” stated Glencore, which now operates the smelter.

Significance

“The Horne deposit—by any criterion including size, grade, or economic and social significance—is a world class ore deposit,” wrote Gibson et al (2000). They noted that the Horne mine and smelter provided the economic impetus and infrastructure that “opened up northwestern Quebec for both settlement and exploration in the early part of the 20th century and contributed, in a broader sense, to the economic growth of Quebec and Canada.”

In June 2005, Noranda Mines merged with Falconbridge, another Canadian company, and continued under the name Falconbridge until it was taken over by Switzerland-based Xstrata in 2006. Xstrata was in turn acquired by another Swiss miner, Glencore, in 2013.

Glencore is still running the Horne smelter in Rouyn-Noranda, and in December 2017 the company celebrated the 90th anniversary of its first casting. According to Glencore, over those 90 years, the smelter produced 12,404,390 tonnes of copper, 40,614,617 ounces of gold and 847,040,998 ounces of silver.