Munro mine, 9 miles east of Matheson, Munro Township, Ontario

The Munro mine lay in Munro Township, in the Larder Lake district of northern Ontario, "9 miles east of Matheson," and was worked by Johns-Manville's Canadian company for its chrysotile fiber.^3,9 Johns-Manville, as Asbestos, the industry's trade journal, reported its announcement in July 1949, placed the new mine "about three quarters of a mile north of the once fabulous Croesus gold mine," on the Ontario Northland Railroad.³ The U.S. Bureau of Mines' Minerals Yearbook for 1949, drawing on the Johns-Manville Stockholders' News, called the company's announcement of "the discovery and projected development of a rich asbestos deposit" "outstanding" news.⁴ A 1971 summary in Asbestos of a report on asbestos in Ontario says that minor quantities had been mined in the province "from 1901 until 1949 when a large deposit of good-grade Chrysotile asbestos was discovered in Munro Township."⁵

Plans and opening

In the July 1949 announcement, Johns-Manville said its board had appropriated funds "to finance immediate development" of the deposit, that stripping would start at once, and that a new mill would be started promptly "so that it can be completely enclosed before winter."³ The company said diamond drilling had reached "a depth of 800 feet" and that "the ore body is 4,200 feet long."³ The planned mill would have "a capacity of 50 tons of mill rock each hour," and the company expected the mine and mill to "provide jobs for 100 to 125 persons."³ In December 1949 the trade journal tied the decision to develop the Munro mine to "the mine strike," which had sharpened interest in new deposits.⁶

The sources expected the mine to open "before May 1950" (Johns-Manville, July 1949) or in "mid-1950" (the Minerals Yearbook and Johns-Manville's chairman, Lewis H. Brown).^3,4,7 They differ on when it did. The Minerals Yearbook for 1950, citing the Northern Miner, says the completed mill "began operation in April," and the 1951 yearbook says the mine "began production in April 1950."^9,10 Johns-Manville's annual report, as Asbestos printed it, said the mine and mill "were placed in production in the middle of the year"; the trade journal itself wrote in 1954 of "the beginning of production in the Spring of 1950."^11,12 Johns-Manville reported that the mine and mill "reached full production in 1951."¹³

The open pit

The company's 1950 annual report said that "the Munro Mine is entirely open-pit method."¹¹ According to the trade journal in 1954, the pit was on the "A" orebody, "which has provided all production to date," and recovery was "chiefly in the form of group No. 4 shingle stock fibre."¹² The Minerals Yearbook for 1951 said the mine was "producing substantial quantities of chrysotile of nonspinning grades," and for 1953 that it had been "operating almost at maximum capacity"; that yearbook placed the mine "near Timmins," where other pages say near Matheson.^2,9

Asbestos reported production of "22,983 tons in 1952" and "some 23,831 tons" in 1953, and called the Munro mine "Ontario's sole asbestos producer."¹² In October 1954 the same journal said the mine "produces about 25,000 tons of asbestos fibre annually."¹⁴ The fiber, the trade journal said, was "a little on the harsh side but is of good quality," and "well suited for the making of wet cement products, such as the Johns-Manville transite pipe."¹² Johns-Manville named Transite pipe, "asbestos roofing and siding shingles" and asbestos paper as products the fiber suited, and the Minerals Yearbook for 1961 said "the harsh fiber was used exclusively in asbestos-cement products."^15,16

In 1954 the trade journal described improved working conditions at the mill, with "new designs of dust hoods on screens and belt conveyors" giving "a better control of dust elimination throughout the processing operations."¹² For its single employees, the journal said, the company "recently built a 30 room Boarding House in Matheson."¹²

Going underground

The Minerals Yearbook for 1953 said the open pit would "meet the present production rate for 3 or 4 years, and plans are being prepared for underground mining"; the trade journal in 1954 put the pit's remaining life at "another 5 to 7 years."^2,12 In July 1954 Johns-Manville's president, A. R. Fisher, said that the sinking of "an 800-foot main shaft, to be supplemented by a 300-foot service shaft, will start this summer," with underground facilities "in operation in about four years."¹⁵ The 1954 yearbook reported "considerable progress" on the shaft-sinking project.¹ Asbestos wrote in January 1957 that "a new shaft has been sunk" and that underground mining "is expected to begin in November 1957."¹⁷ In 1959 the trade journal listed the mine as "developing underground block-caving system in readiness for switch over from present open pit mining," and the Minerals Yearbook said programs had been started "to convert from open-pit to underground mining at the Munro mine."^18,19

The Minerals Yearbook for 1960, citing the Northern Miner, reported that "since conversion to underground mining, the ore recovered was reported to be considerably higher grade than that obtained from open pit operations."²⁰ Exploration that year "revealed new ore bodies between the two main ore zones, below the main 637-foot haulage level," and changes were made in the mill "to improve the quality of fiber produced."²⁰ For 1961 the yearbook reported that "grouting around the edges of the abandoned open pit was necessary to reduce inflow of surface water to underground workings," that a third stope was opened, and that a new milling stage "increased capacity 20 to 25 percent."¹⁶ It gave mill output as "2,500 tons of asbestos per month, all classified as M-100."¹⁶ In 1962 the main shaft "was deepened 300 feet below the 637-foot level in preparation for a second production level."²¹

The end

The Minerals Yearbook for 1964, citing Mining Engineering, called the Munro mine "the only producing mine in Ontario" and reported that its operations "were terminated in August."⁸ Asbestos reported in December 1965 that Johns-Manville "terminated operations at Munro mine," and that the Munro mill had been "converted to test ore in various milling processes."²² Looking back in 1971, the trade journal said that the Munro mine "was a substantial producer for a period of 14 years."⁵

The documents report this mine producing asbestos fiber for sale.¹²

Location

Output the documents report

Figures as printed, in the units each document uses (short tons before about 1990, metric tons after, in most U.S. chapters). Some are a year's output, some a daily rate or a capacity, some a company's total rather than this mine's alone; the statement for that year below says which.

Year	Figure	Source
1952	22,983 tons	12
1953	23,831 tons	12
1954	25,000 tons of asbestos fibre annually	14
1955	571,822 tons of fibre	23
1961	2,500 tons of asbestos per month	16

Year by year

Every statement about this mine in the documents, in each document's own words, by the year it is about.

1949

• Mill: “construction of a new mill will also be started promptly” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 48³
• Mill: “The new mill will have a capacity of 50 tons of mill rock each hour” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 48³
• Exploration: “Funds have been appropriated ... to finance immediate development of a rich, new asbestos ore deposit in northern Ontario” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 48³
• Description: “located in Munro Township about three quarters of a mile north of the once fabulous Croesus gold mine” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 48³
• Workforce: “Initial operation of the mine and mill will provide jobs for 100 to 125 persons” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 48³
• Reserves: “ore body ... diamond drilling ... depth of 800 feet ... The ore body is 4,200 feet long” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 48³
• Exploration: “the decision of Johns-Manville to develop the Munro Mine in Ontario” (Johns-Manville), p. 10⁶
• Exploration: “the discovery and projected development of a rich asbestos deposit 9 miles east of Matheson” (Johns-Manville Co.), as reported by Johns-Manville Stockholders' News, p. 8⁴
• Mill: “A new mill having an hourly capacity of 50 tons of mill rock is to be built” (Johns-Manville Co.), as reported by Johns-Manville Stockholders' News, p. 8⁴
• Output: “the Munro Mine was a substantial producer for a period of 14 years”, p. 37⁵

1950

• Opened: “mining operations are expected to begin about the middle of 1950” (Johns-Manville), p. 10⁶
• Opened: “the new Canadian Johns-Manville Munro Mine, near Matheson, Ontario, is planned to begin operations in mid-1950” (Canadian Johns-Manville), said by Lewis H. Brown, Chairman of the Board, Johns-Manville Corporation, as reported by Asbestos (magazine), p. 13⁷
• Opened: “mine production was expected in mid-1950” (Johns-Manville Co.), as reported by Johns-Manville Stockholders' News, p. 8⁴
• Opened: “placed in production in the middle of the year” (Johns-Manville Corporation), said by Johns-Manville Corporation (annual report; Lewis H. Brown, Chairman), as reported by Asbestos (magazine), p. 42¹¹
• Description: “entirely open-pit method” (Johns-Manville Corporation), said by Johns-Manville Corporation (annual report; Lewis H. Brown, Chairman), as reported by Asbestos (magazine), p. 42¹¹
• Mill: “In 1950 Johns-Manville completed construction on the Munro mine and mill” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 54²⁴
• Opened: “Since the beginning of production in the Spring of 1950” (Canadian Johns-Manville Company, Limited), p. 10¹²
• Worked: “has been operated since 1950 as an open pit” (Canadian Johns-Manville Corp.), p. 10¹
• Opened: “began commercial production of fiber for asbestos cement in 1950” (Canadian Johns-Manville Co., Ltd.), as reported by Mining Engineering, p. 6⁸
• Opened: “began operation in April” (Canadian Johns-Manville Corp.), as reported by Northern Miner, p. 8¹⁰
• Mill: “The completed mill of the Canadian Johns-Manville Corp. in Munro Township, Cochrane District, Ontario, began operation in April” (Canadian Johns-Manville Corp.), as reported by Northern Miner, p. 8¹⁰
• Opened: “The Munro mine ... began production in April 1950” (Canadian Johns-Manville Corp.), p. 8⁹
• Opened: “the mine is expected to be in production before May 1950” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 48³

1951

• Output: “is producing substantial quantities of chrysotile of nonspinning grades” (Canadian Johns-Manville Corp.), p. 8⁹
• Opened: “The Munro asbestos mine and mill near Matheson, Ontario, begun in 1949, reached full production in 1951” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 41¹³

1952

• Output: “22,983 tons in 1952” (Canadian Johns-Manville Company, Limited), p. 10¹²

1953

• Reserves: “Large reserves are said to exist in other nearby properties owned by the company” (Johns-Manville Corp.), p. 9²
• Reserves: “The open pit now worked will meet the present production rate for 3 or 4 years” (Johns-Manville Corp.), p. 9²
• Exploration: “plans are being prepared for underground mining” (Johns-Manville Corp.), p. 9²
• Worked: “The Munro mine of the Johns-Manville Corp. near Timmins, Ontario, has been operating almost at maximum capacity” (Johns-Manville Corp.), p. 9²
• Workforce: “the Company recently built a 30 room Boarding House in Matheson” (Canadian Johns-Manville Company, Limited), p. 10¹²
• Output: “Production at the Munro Mine ... amounted in 1953 to some 23,831 tons” (Canadian Johns-Manville Company, Limited), p. 10¹²
• Dust and health: “Through new designs of dust hoods on screens and belt conveyors, a better control of dust elimination” (Canadian Johns-Manville Company, Limited), p. 10¹²

1954

• Description: “The present pit is on the "A" orebody ... The mine has three other orebodies” (Canadian Johns-Manville Company, Limited), p. 10¹²
• Description: “It is estimated that the open pit will meet the present production rate for another 5 to 7 years” (Canadian Johns-Manville Company, Limited), p. 12¹²
• Buyers: “well suited for the making of wet cement products, such as the Johns-Manville transite pipe” (Canadian Johns-Manville Company, Limited), p. 10¹²
• Description: “Sinking of an 800-foot main shaft, to be supplemented by a 300-foot service shaft, will start this summer” (Johns-Manville Corporation), said by A. R. Fisher, President, Johns-Manville Corporation, as reported by Asbestos (magazine), p. 46¹⁵
• Buyers: “The Munro fibre is particularly suitable in wet processes ... Transite pipe, asbestos roofing and siding shingles and ... asbestos paper” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 46¹⁵
• Output: “the Munro Mine, which produces about 25,000 tons of asbestos fibre annually” (Johns-Manville), p. 22¹⁴
• Exploration: “considerable progress was made in 1954 on a shaft-sinking project for development of underground facilities” (Canadian Johns-Manville Corp.), p. 10¹

1955

• Description: “the open pit at the Munro mine” (Johns-Manville Corp., Ltd.), as reported by Pit and Quarry, p. 11²⁵
• Exploration: “shaft sinking at the Munro mine” (Johns-Manville Corp., Ltd.), as reported by Northern Miner, p. 11²⁵
• Exploration: “preliminary plans for opening new ore bodies in the Matheson area” (Johns-Manville Corp., Ltd.), as reported by Northern Miner, p. 11²⁵
• Exploration: “development of underground mining at the company's Munro mine in Northern Ontario” (Johns-Manville Corporation), said by Johns-Manville Corporation, as reported by Asbestos (magazine), p. 48²⁶
• Output: “At both locations a total of 571,822 tons of fibre were produced last year” (Canadian Johns-Manville Co., Ltd.), p. 4²³

1956

• Exploration: “at Munro, Ontario, where the company also is converting to underground mining operations” (Canadian Johns-Manville Co., Ltd.), p. 4²³
• Exploration: “While open pit mining proceeds, a new shaft has been sunk. Underground mining at the J-M Munro Mine is expected to begin in November 1957” (Johns-Manville), p. 60¹⁷
• Exploration: “underground development is progressing to prepare for a transposition from open pit mining to block caving” (Canadian Johns-Manville Company Limited), p. 16²⁷

1958

• Output: “the development of the Munro Mine (2), in Beatty Township, has led to an ever increasing output. At present, this mine accounts for practically all the asbestos recovered from this field”, p. 6²⁸

1959

• Exploration: “Munro Mine. Matheson, Ont. Developing underground block-caving system in readiness for switch over from present open pit mining” (Canadian Johns-Manville Limited), p. 12¹⁸
• Reserves: “the estimated reserves at Cassiar in British Columbia and at the Munro Mine in Ontario, together amount to over 10,000,000 tons”, p. 6²⁹
• Description: “to convert from open-pit to underground mining at the Munro mine” (Canadian Johns-Mansville Co., Ltd.), p. 6¹⁹

1960

• Mill: “Procedure at the former follows closely that at Jeffrey”, p. 12³⁰
• Description: “Since conversion to underground mining, the ore recovered was reported to be considerably higher grade than that obtained from open pit operations” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 7²⁰
• Exploration: “revealed new ore bodies between the two main ore zones, below the main 637-foot haulage level” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 7²⁰
• Description: “Block-caving methods at the ... Munro Mine, Ontario”, as reported by Canadian Mining and Metallurgical Bulletin (Montreal), p. 11²⁰
• Mill: “Changes were made in the mill to improve the quality of fiber produced” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 7²⁰

1961

• Buyers: “The harsh fiber was used exclusively in asbestos-cement products” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 8¹⁶
• Mill: “A new milling stage increased capacity 20 to 25 percent by preconcentration” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 8¹⁶
• Exploration: “Downward continuation of the main ore zone ... was explored at the 900-foot level” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 8¹⁶
• Exploration: “A third stope was opened during 1961, and another was in preparation above the main 637-foot haulage level” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 8¹⁶
• Description: “Grouting around the edges of the abandoned open pit was necessary to reduce inflow of surface water” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 8¹⁶
• Output: “Mill output was 2,500 tons of asbestos per month, all classified as M-100” (Canadian Johns-Manville Co., Ltd.), as reported by Northern Miner (Toronto), p. 8¹⁶

1962

• Output: “Two grades of fiber were produced” (Canadian Johns-Manville Co., Ltd.), p. 9²¹
• Exploration: “The main shaft ... was deepened 300 feet below the 637-foot level in preparation for a second production level” (Canadian Johns-Manville Co., Ltd.), p. 9²¹

1964

• Description: “was the only producing mine in Ontario” (Canadian Johns-Manville Co., Ltd.), as reported by Mining Engineering, p. 6⁸
• Closed: “Operations ... were terminated in August” (Canadian Johns-Manville Co., Ltd.), as reported by Mining Engineering, p. 6⁸

1965

• Mill: “Munro mill which has been converted to test ore in various milling processes” (Johns-Manville Corporation), p. 3²²
• Closed: “Johns-Manville Corporation terminated operations at Munro mine” (Johns-Manville Corporation), p. 3²²
• Closed: “the shutdown of the Johns-Manville Co. Ltd. plant at Matheson, Ontario” (Johns-Manville Co. Ltd.), p. 7³¹

Other names

Documents call this mine “rich asbestos deposit 9 miles east of Matheson”, “Munro mine”, “Munro Mine”, “Munro mill”.

See also

• Munro mine in the Lexicon
• Johns-Manville Co.: the company's history, documents, people, products and plants
• Canadian Johns-Manville Corp.: the company's documents, people, products and plants
• All asbestos mines

References

1. Minerals Yearbook: Asbestos Chapters, 1954 (January 1, 1955), p. 10.
2. Minerals Yearbook: Asbestos Chapters, 1953 (January 1, 1954), p. 9.
3. Asbestos Magazine, 1949, July 1949 (July 1, 1949), p. 48.
4. Minerals Yearbook: Asbestos Chapters, 1949 (January 1, 1950), p. 8.
5. Asbestos Magazine, 1971, September 1971 (September 1, 1971), p. 37.
6. Asbestos Magazine, 1949, December 1949 (December 1, 1949), p. 10.
7. Asbestos Magazine, 1950, January 1950 (January 1, 1950), p. 13.
8. Minerals Yearbook: Asbestos Chapters, 1964 (January 1, 1965), p. 6.
9. Minerals Yearbook: Asbestos Chapters, 1951 (January 1, 1952), p. 8.
10. Minerals Yearbook: Asbestos Chapters, 1950 (January 1, 1951), p. 8.
11. Asbestos Magazine, 1951, February 1951 (February 1, 1951), p. 42.
12. Asbestos Magazine, 1954, April 1954 (April 1, 1954), pp. 10, 12.
13. Asbestos Magazine, 1952, February 1952 (February 1, 1952), p. 41.
14. Asbestos Magazine, 1954, October 1954 (October 1, 1954), p. 22.
15. Asbestos Magazine, 1954, July 1954 (July 1, 1954), p. 46.
16. Minerals Yearbook: Asbestos Chapters, 1961 (January 1, 1962), p. 8.
17. Asbestos Magazine, 1957, January 1957 (January 1, 1957), p. 60.
18. Asbestos Magazine, 1959, July 1959 (July 1, 1959), p. 12.
19. Minerals Yearbook: Asbestos Chapters, 1959 (January 1, 1960), p. 6.
20. Minerals Yearbook: Asbestos Chapters, 1960 (January 1, 1961), pp. 7, 11.
21. Minerals Yearbook: Asbestos Chapters, 1962 (January 1, 1963), p. 9.
22. Asbestos Magazine, 1965, December 1965 (December 1, 1965), p. 3.
23. Asbestos Magazine, 1956, March 1956 (March 1, 1956), p. 4.
24. Asbestos Magazine, 1953, July 1953 (July 1, 1953), p. 54.
25. Minerals Yearbook: Asbestos Chapters, 1955 (January 1, 1956), p. 11.
26. Asbestos Magazine, 1956, February 1956 (February 1, 1956), p. 48.
27. Asbestos Magazine, 1957, April 1957 (April 1, 1957), p. 16.
28. Asbestos Magazine, 1958, October 1958 (October 1, 1958), p. 6.
29. Asbestos Magazine, 1959, September 1959 (September 1, 1959), p. 6.
30. Asbestos Magazine, 1960, March 1960 (March 1, 1960), p. 12.
31. Minerals Yearbook: Asbestos Chapters, 1965 (January 1, 1966), p. 7.