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By E. Sirolli

In recent times, with rare exceptions, most economically viable ore discoveries have been large, low-grade and located in remote parts of the world. Mining companies have often shown to be incapable of mitigating their social and economic impact on local communities. Sustainable development and relations can be achieved by implementing bottom-up methodologies to the top-down tools already in use by mining companies. In order to magnify the importance of enterprise facilitation as a primary method for community development, data from 25 years of community based work around the world was used. Results highlight the need for a grassroots approach to local economic and community development, which focuses on the creation of a parallel economy in communities. Using solely top-down methodologies for developing community relations is shown to be a limited resource for mining companies. There are fundamentally two dangers for mining companies: alienating the local population, resulting in militancy and lengthy legal battles to obtain a license to operate; and, being accountable for building social and economic infrastructure that are not the company?s responsibility.

Jan 1, 2012

By Parker A. J, Ruane M, Wadley L. G B

Copper, sulphur, nickel, cobalt, palladium, silver, and gold can be recovered from the copper sulphide precipitated from the "copper boil" of the Sherritt-Gordon nickel process used at Western Mining Corporation's Kwinana nickel <refinery. The method is based on an oxidative ammonia leach of copper, nickel, and the precious metals at temperatures below 40°C to produce, in part, elemental sulphur, in the residue. This is followed by heating to decompose thiosulphate and remove some ammonia with precipitation of some of the copper, palladium, gold, and silver. Addition of sulphur dioxide to pregnant liquor precipitates copper, as either Chevreul's salt or copper(I) ammonium sulphite, together with the remaining gold and silver. Less than 10 per cent of the dissolved palladium and less than 1 per cent of nickel and cobalt precipitate to this stage.In one option, the Chevreul's salt is dissolved in a solution of copper(II) sulphate, acetonitrile, and water to generate a solution of copper(I) sulphate. Gold and silver do not dissolve. The solution of copper(I) sulphate is thermally disproportionated by distilling acetonitrile to give exceptionally pure copper powder, with desirable characteristics for powder metallUrgy. Nickel, cobalt, and ammonium sulphate are recovered from the motherliquor of the Chevreul's salt precipitation by return to the Sherritt-Gordon process, where recovery procedures already exist. Palladium is recycled for eventual removal as a sulphide with the gold and silver.In the other option, solid copper(I) ammonium-sulphite is <thermally disproportionated in water at 150°C to copper powder.

Jan 1, 1978

By Bruno Bussière, Guosheng Zhan, Michel Aubertin, Vincent Martin, Robert P. Chapuis

The study evaluates the hydrological behaviour of exposed and covered waste rock dumps. The objectives were to determine the major factors influencing unsaturated flow in waste rock dumps and covers, and to improve the in-situ, laboratory and numerical modeling characterization methods. Using material properties obtained from in-situ and laboratory tests, waste rock dumps of different configurations, with and without covers, were modeled. It was found that a properly designed “Store, divert and release” (SDR) cover allows most of the water to be diverted downslope and discharged outside of the waste rock dumps. The SDR cover seems to work efficiently even in extreme storm events. The numerical modeling results show that the unsaturated hydraulic properties (e.g. air entry value and water entry value) of the materials largely control the infiltration of water into waste rock dumps.

Jan 1, 2005

By Matthew Holden, Jason Emery, Matthew Benjamin, Peter Craig

Over the last 25 years, through adversity and a growing level of risk mitigation, Australian Longwall mines have been using higher and higher capacity cable bolts for secondary support. A recent survey revealed 85% of Australian longwall cable bolts are a 70 tonne capacity pre-tensioned hollow post groutable system. Mines avoiding pumping cementitious grouts are sometimes using pre-tensioned resin encapsulated solid cable bolts of over 90 tonne capacity. Results from various industry and University research has led to manufacturer's fine tuning the construction of their cable bolts. A review of this research explains how smooth wire construction is now dominant. Aggressive shear has also led to some mines using 8 tonnes pre-tension instead of the previous common 20 tonnes pre-tension. Lower pre-tension acceptance is now leading to a greater use of threaded cable bolt end fittings, these are tensioned to 8 tonne using the drill motor torque. A recent development is the TEX cable bolt, a slim line threaded end fitting that fits with the drill hole like a standard rock bolt. This cable is being installed at the coal face as primary support off bolter-miners. The laboratory and in-situ testing of the TEX cable is presented. In a bid to improve gateroad development rates and ground support in the last several years, a 100 tonne tensile capacity Goliath cable system was developed. The latest development in resin anchored solid cables is a 110 tonne capacity cable bolt, with laboratory and in-situ testing results presented.

Jun 25, 2024

By Russel Delmar

Construction of Ontario Power Generation?s 12.8-m diameter, 10.4-km long water diversion tunnel in Niagara Falls, Ontario, is underway. The tunnel is being excavated by means of a 14.44-m diameter open gripper Tunnel Boring Machine. The tunnel lining is constructed as a two-pass system with the initial lining consisting of rock bolts, mesh, steel channels or ribs, and shotcrete, and the final lining consisting of pre-stressed cast-in-place concrete with a waterproof membrane. This paper describes salient design and construction aspects as follows: ? Regional and Site Geology ? Tunnel Layout and Design ? TBM Tunnelling and Cast-in-place Concrete Lining Construction

Jan 1, 2008

By Lees M. G, Vitnell B. W

The post-war need to increase coal production promoted an intensive drilling campaign. Ineffectiveness in core recovery inclined the coal industry towards percussion drilling rather than diamond drilling. The Joint Coal Board, recognising the greater potential of core drilling, has actively encouraged improvement in techniques and equipment. One outstanding need was a barrel which, over and above other improvements being achieved, would permit recovered core to be examined before it had been subjected to the increased fragmentation and displacement which to date has been inevitable except in core which has been drilled in solid sticks û as New South Wales coal rarely can be drilled. In conjunction with Triefus Pty Ltd a barrel with a split inner tube has now been evolved, as a result of which, core can be more accurately logged, division in to lengths for analysis more aptly made, any core loss more reasonably allocated to appropriate plies, and a greater percentage of core recovered û of the order 95 per cent and more. The one half of the split inner tube is lifted from the other and the logging completed before the core is disturbed.

Jan 1, 1957

By G. K. Jorgenson, S. H. Chung

"IntroductionThe SABREX Blast Modelling Program was developed jointly by the companies of the ICI Explosives Group, of which C-I-L Inc. is a member. SABREX (Scientific Approach to Breaking Rock with Explosives) is a modular computer program which incorporates new technology with a number of tested programs that have been in use world wide.SABREX predicts the performance of blasts in terms of (I) fragment size and distribution; (2) muckpile profile and face velocity; (3) grade fracture; (4) collar breakage; (5) a rupture envelope which depicts crack penetration behind and beneath blastholes; and (6) a complete cost analysis including explosives, drilling and accessory costs. The predicted blast results are displayed as dynamic colour graphics and in tabular form.SABREX uses data on the detailed geometry of the drilled and loaded pattern, detonation characteristics of the explosives and the dynamic properties of the rock to generate blast predictions. SABREX blasting calculations take into account the effects that shock and quasi-static pressures exert on the rock around the blastholes. While physical effects occur very rapidly in rock blasting, it is possible to view and model the sequence of events as discrete sections.The program can be run on a microcomputer and is currently operated by C-I-L technical service staff in Canada for the use of drilling and blasting operators.Figure I is a diagram representing the modules of the program and associated technology that is used to complement the program.Any, or all, of the modules may be used in a particular study or blast optimization. Because the BOBCAT module of the SABREX program has been described in previous papers(7.8.9), this discussion will concentrate on the newer modules: CRACK, HEAVE, RUPTURE ENVELOPE and to a limited extent, KUZ-RAM, which present a more detailed picture of the blasting process.Each of these modules is discussed in terms of the information they offer the operator in analyzing the blast. Specific examples of recent usage in Canadian mining situations are included to illustrate the ability of the model to produce practical results that can assist in optimizing actual blasting operations or solving problems that do exist."

Jan 1, 1987

Cobalt/tungsten mineralization at Mt. Cobalt, located 170 km southeast of Mt. Isa in northwestern Queensland, is described. Mineralization occurs in the Kuridala Formation of the Mary Kathleen Group, which is composed dominantly of pelitic schists, carbonates and acid and basic volcanics.Rocks in the region are metamorphosed to amphibolite facies and affected by two generations of tight to isoclinal folds and a third, more open generation of folds. The region is divided into three meridionally trending belts on the basis of structural style, with mineralization concentrated in the central, more highly strained belt.Deformation and metamorphism is probably younger than 1670 m.a., and the rocks are intruded by granitic rocks dated at 1509 ± 22 m.a.Mineralization occurs in shear zones at the contact between an amphibolite and enclosing pelitic schists, and within the amphibolite itself. Mineralization consists of cobaltite and scheelite with lesser chalcopyrite, pyrite, pyrrhotite, i1menite, allanite, xenotime and apatite. The mineralizing event involved addition of K, Cl, CO2 W, As, Cu, Ni, Au and rare earths and depletion of Ca and Na. It altered a hornblendeandesine/labradorite host assemblage to a biotiteoligoclase/andesine-scapolite assemblage. Though tourmalinealteration also occurs, it is probably not related to mineralization.It is concluded that the mineralization and alteration assemblages formed by reaction of saline fluids with amphibolite close to the peak of amphibolite facies metamorphism.The fluids are probably metamorphically derived, and their movement was channelled through high strain zones in the sequence. The material carried by the fluids was derived from the metasedimentary/metavolcanic pile as a whole.Other deposits in the Mt. Cobalt-Selwyn area have characteristics comparable with Mt. Cobalt, and the mechanism for the genesis of Mt. Cobalt may have applications at other areas in the region.

Jan 1, 1983

By Norman Marr

Introduction In Canada, the mining industry and water-power development are intimately associated in that mining, which ranks second among the country's primary industries, depends principally upon hydro-electric energy for its large power requirements. On the whole, the Dominion has been very favourably endowed with water-power resources; generally speaking it is a well-watered country with numerous rivers and lakes located in are as where the topography favours water-power development. Precipitation, the raw material of water power, varies from an annual fall of more than l00 inches on the Pacific coast to about 12 inches in sections of the Prairies and the Northwest Territories; in Ontario and Quebec the annual average is 24 to 40 inches and in Nova Scotia about 45 inches. In its descent to the sea, the resulting run-off, much of it from considerable altitudes, creates sources of potential energy at every rapid and fall along the country's many streams and rivers. Many of the innumerable lakes in the Dominion provide storage basins for the regulation of stream flow, thus enhancing the potential power of available sites. While water-power resources are fairly well distributed across the Dominion, as is shown on the accompanying map of Canada showing power sites (Figure 1), it is particularly fortunate that those areas which are lacking in indigenous fuels have been compensated in large degree for this scarcity by being favoured with a high proportion of the total potential water power. This has an important bearing on the mining industry in that extensive mining operations can be economically carried out in the great Canadian Shield, which is lacking in commercial coal deposits but is rich in water-power resources. This Precambrian formation, which forms a wide belt around Hudson bay and in which many metalliferous ores are found, was 'subject to severe glaciation in a recent geological period, so that its river systems are comparatively young and are characterized by numerous lakes joined by short reaches of fast water, rapids, and falls which offer frequent opportunities for power development. The western Cordilleran region, which also is important in mining, has abundant water power. The accompanying geological map (Figure 2), prepared by the Geological Survey of Canada, shows the great extent of the Precambrian and Cordilleran regions and may be compared with the map of water-power sites to show the high incidence of water-power resources in these potential mining areas in which important mineral discoveries have already been made.

Jan 1, 1949

By Michael Gauna, Christopher Mark

"For decades, pillar recovery accounted for a quarter of all roof fall fatalities in underground coal mines. Studies showed that a miner on a pillar recovery section was at least three times more likely to be killed by a roof fall than other coal miners. Since 2007, however, there has been just one fatal roof fall on a pillar line. This paper describes the process that resulted in this historic achievement. It covers both the key research findings and the ways in which those insights, beginning in the early 2000s, were implemented in mining practice.One key finding was that safe pillar recovery requires both global and local stability. Global stability is addressed primarily through proper pillar design, and became a major focus after the 2007 Crandall Canyon mine disaster. But the most significant improvements resulted from detailed studies that showed that local stability, defined as roof control in the immediate work area, could be achieved with three interventions:• Leaving an engineered final stump, rather than extracting the entire pillar;• Enhancing roof bolt support, particularly in intersections, and• Increasing the use of Mobile Roof Supports (MRS)A final component was an emphasis on better management of pillar recovery operations. This included a focus on worker positioning, as well as on the pillar and lift sequences, MRS operations, and hazard identification. As retreat mines have incorporated these elements into their Roof Control Plans, it has become clear that pillar recovery is not ""inherently unsafe.""The paper concludes with a discussion of the challenges that remain, including the problems of rib falls and coal bursts.INTRODUCTIONPillar recovery has always been an integral part of underground coal mining in the US. When room-and-pillar methods are employed, large blocks of coal in the form of pillars are initially left in place to support the weight of the overburden. Unless these pillars are subsequently recovered, the coal they contain will never be mined."

Jan 1, 2016

By M. M. Gilkey

This report describes the effects of water shortage on Arizona's mineral industries. The information presented was obtained in interviews with company representatives. Operations covered included all State metal mines using substantial quantities of water and all concentrators and smelters. Also included in the survey were 8 operations in the nonmetallic group; 22 in the plating, metal-fabricating, and metal-forming categories; 1 public-utility power company; and 6 water companies. The extent of the water shortage in Arizona is reflected in mineral- industry water-use practices, in the high cost and low quality of water used at many operations, and in the stringency of State control of well drilling and pumping. Many mineral-industry operations are among those users most seriously affected by the uneven water supply.

Jan 1, 1963

By M. M. Gilkey

This report describes the effects of water shortage on Arizona's mineral industries. The information presented was obtained in interviews with company representatives. Operations covered included all State metal mines using substantial quantities of water and all concentrators and smelters. Also included in the survey were 8 operations in the nonmetallic group; 22 in the plating, metal-fabricating, and metal-forming categories; 1 public-utility power company; and 6 water companies. The extent of the water shortage in Arizona is reflected in mineral- industry water-use practices, in the high cost and low quality of water used at many operations, and in the stringency of State control of well drilling and pumping. Many mineral-industry operations are among those users most seriously affected by the uneven water supply.

Jan 1, 1963

By M. M. Poulton

Universities are not immune from the large number of retirements facing the mining industry. Department heads anticipate that we will need to replace all of the senior mining engineering faculty in the U.S. by 2020. Long term studies of Ph.D. completion times and success rates indicate that in Engineering disciplines in the U.S., the ten year completion rate is 65% at best and the four year completion rate is less than 8%. We do not have accurate data on completion rates and times for mining or metallurgical engineering Ph.D. students in the U.S. but students self-report their expected completion times are around 4 years. National data on doctoral students indicate that younger, full time students with sufficient financial support have a higher probability of success in completing their degrees in a timely manner. Students in Eastern U.S. mining engineering programs are on average 32 years old, 85% are full time, and the gap between support and cost of attendance is $5,000 per year. Students in Western U.S. programs are on average 38 years old, 78% are full time, and the financial gap is $8,483. Further, it appears that domestic graduate students are not very geographically mobile. The current demand for new faculty is higher in Western programs but the longer term retirements are higher in Eastern programs. While all Ph.D. students who responded to the 2010 survey indicated an interest in a faculty position at some point in their careers, very few were applying for the open positions. Over the past 35 years for which data could be obtained, the maximum number of Ph.D. students enrolled in mining engineering in the U.S. is 115 with a maximum of 27 degrees granted in one year. On average 89 students are enrolled in doctoral programs in mining engineering in the U.S. with average degree production of 15 Ph.D.s per year.

Jan 1, 2012

By Ross Nairn

"Tulawaka Mine is a joint venture between Pangea Minerals Limited 70% (a wholly-owned subsidiary of Barrick Gold Corporation) and Northern Mining 30%. Tulawaka Mine is located in North West of Tanzania in the Lake Victoria Goldfields. Tulawaka Mine is scheduled to process 360,000 tonnes per year at an average 11.5 g/t head grade over a 4 year mine life.The Tulawaka Process Plant uses single stage crushing, single stage SAG milling, gravity, intensive leach of gravity concentrates, CIL, Zadra desorption and cyanide detoxification to process the ore. Gold recovery exceeds (or is expected to) 95%.The Process Plant was designed and constructed under the supervision of Ausenco Engineering of Australia. Site works commenced in January 2004, Process Plant construction commenced in July 2004 and the first ore was presented to the Process Plant 26th February 2005. The first gold was poured on 15th March 2005. All construction contractors were demobilized from site 7th April 2005. Major achievements have been 3.4 million hrs LTI free during construction and operation to date, training of the Tanzanian workforce at Bulyanhulu Mine prior to commissioning, a succession plan to replace expatriate personnel with Tanzanian staff and significant over performance of the Process Plant against design.INTRODUCTIONTulawaka Mine is situated approximately 160 km south west of Mwanza in the western Lake Victoria Goldfields District of north western Tanzania. The property is held under a joint venture between Pangea Goldfields Inc (70%), a wholly owned subsidiary of Barrick Gold Corporation, and Explorations Minieres Du Nord Ltée (30%). A location map showing the position of the operation in Tanzania is shown in Figure 1.Mine site staff at Tulawaka comprises a combination of Tanzanian and Expatriate personnel. All Pangea personnel live on site and commute to their place of residence for their R&R on a 9 weeks on 4 weeks off roster."

Jan 1, 2006

Background information, formulae and a systematic set of procedures for estimating capital and operating costs for open pit mining equipment are presented in this paper. Firstly, equipment capital costs are required. These can be obtained from either suppliers, contractors or from first principles. The equipment is then divided into cost elements. Typically these are fuel and power requirements, spare parts consumption, wear items such as tyres, teeth and drill bits and finally repair and operating labour requirements. By consideration of the cost and life of each element a base cost can be derived. The base cost is then adjusted to suit specific site conditions such as the proximity to spare parts suppliers, the duty or ground conditions and the management and operator skills specific to the site. Hence, the same item of equipment can be costed to reflect different operations. Included are tables and data for typical plant items. Several examples are also given to illustrate the methodology being presented. The intention is to provide a set of procedures to allow costs to be built up from base level in a systematic and repeatable way. Applications for these costs include feasibility studies, budgetting and data for economic analyses.

Jan 1, 1990

By Michael Godard, Peter Cleyle

"Suncor Energy’s Project Millennium increased oilsands production capacity by an additional 95,000 barrels per day to its present level of 225,000 barrels per day. This massive venture included an expanded Mine, new Extraction and Upgrading facilities, as well as, steam and utilities infrastructuresIn the Primary Extraction process, removal of the bitumen from the oil sand begins with slurry preparation and is followed by primary , secondary and tertiary separation processes. The final cleaning step of the bitumen froth is the Secondary Extraction process, that removes residual water, mineral and solids to produce a clean diluted bitumen suitable for Upgrader feedstock.This paper will review the flowsheet of the Millennium Primary Extraction facility, from its recent commissioning through the ramp up to design production rates. In addition, new technologies in the Primary Extraction flowsheet will be reviewed.INTRODUCTIONAs conventional supplies of oil and gas are depleted in Canada, the Athabasca oil sands industry of Alberta becomes an increasingly important source of energy. Today, high quality crude from Alberta’s oil sands accounts for roughly 30% of Canada’s daily petroleum production. According to government projections, over the next 7 years, oil sands production is expected to more then double, and by 2010 more than half of Canada’s crude oil is expected to come from the oil sands.Oil sands deposits consist of a layer of sand saturated with bitumen covered by a muskeg overburden and underlain by silt and clay. The oil sand is mined where the overburden is economical to remove, typically less than thirty meters thick. The Athabasca oil sand deposits around Fort McMurrray is ideal for mining. Bitumen can be described as a diverse collection of hydrocarbons, organosulfur, and nitrogen compounds."

Jan 1, 2004

By Adrian Moore, Alan Richards, Andrew Brodbeck

Structural blast vibration limits should be based on the strength of the structure, the stress induced by blasting, and a responsible factor of safety. In this paper a methodology that uses direct strain measurements to determine the stress induced by blasting is described. The methodology has been used to measure strain resulting from blasting, and establish appropriate blast vibration limits on a brick sewer tunnel, an underground mine heading, brick veneer houses, a water pipeline, and transmission tower foundations. An outline is given of the use of the methodology to establish limits for the main entry heading of an underground coal mine, and transmission tower footings. The methodology that is described has reduced uncertainty factors, and permitted the specification of higher blast vibration limits than had been previously used.

By James J. Halbouty, Michel T. Halbouty

Drilling activity in the South Texas area, which includes the South Corpus Christi and Laredo districts, showed a marked decline during 1941 from that of the preceding year. The rate of new discoveries, however, 'compared favorably with exploratory results of 1940 because of the many new productive sands opened in existing fields. South Texas completions for 1941 were about 12.3 per cent below the 1940 figure, compared with an increase of approximately 5.5 per cent in the total number of completions in the United States during 1941 over the 1940 total. During the year, 1452 wells were drilled in this area; of these, 1205 were drilled in or as extensions to the proven fields, and 247 were rank wildcats drilled in search of new producing pools. The comparable 1940 figures were: 1320 field or extension wells and 336 rank wildcats, a total of 1656 completions. This represents a decline in 1941 of approximately 8.7 per cent in proven-area wells, and of about 26.5 per cent in rank wildcats. It must be stressed that wells that were considered rank wildcats at the beginning of operations, but which opened production later classified as additions to existing fields, are not regarded as rank wildcats in this and previous annual reports on this same area. These wells are classified as semiwildcats (Table 2). There were 13 new oil or distillate fields and 4 new gas areas opened during the year, as listed in the next column. This listing represents a decline of 32 per cent from the 25 new areas found during the previous year, and to a great extent can be attributed to the 26.5 per cent decline in wildcatting. The rate of new discoveries based on the 247 wildcats was 14.5 to I, which compares somewhat unfavorably with the 13.4 to I ratio obtained in 1940 (Table 5). Dry wildcats totaled 230. The proof of the prolific character of the South Texas area as a source of petroleum reservoirs is to be found in the fact that of the 1205 field or extension (semiwildcat) wells completed during the past year 61 opened production from new sands or found crude in formerly distillate-producing sands. The 1940 total of 1320 such wells accounted for 50 horizons that provided either new production or crude in distillate sands, and in this respect the 1941 rate of discovery shows to greater advantage, the ratios for new sands being 19.7 to I for 1941 and 26.4 to I for 1940. The 1205 field or semiwildcat wells completed in 1941 resulted in 926 oil or dis-

Jan 1, 1942

By James J. Halbouty, Michel T. Halbouty

Drilling activity in the South Texas area, which includes the South Corpus Christi and Laredo districts, showed a marked decline during 1941 from that of the preceding year. The rate of new discoveries, however, 'compared favorably with exploratory results of 1940 because of the many new productive sands opened in existing fields. South Texas completions for 1941 were about 12.3 per cent below the 1940 figure, compared with an increase of approximately 5.5 per cent in the total number of completions in the United States during 1941 over the 1940 total. During the year, 1452 wells were drilled in this area; of these, 1205 were drilled in or as extensions to the proven fields, and 247 were rank wildcats drilled in search of new producing pools. The comparable 1940 figures were: 1320 field or extension wells and 336 rank wildcats, a total of 1656 completions. This represents a decline in 1941 of approximately 8.7 per cent in proven-area wells, and of about 26.5 per cent in rank wildcats. It must be stressed that wells that were considered rank wildcats at the beginning of operations, but which opened production later classified as additions to existing fields, are not regarded as rank wildcats in this and previous annual reports on this same area. These wells are classified as semiwildcats (Table 2). There were 13 new oil or distillate fields and 4 new gas areas opened during the year, as listed in the next column. This listing represents a decline of 32 per cent from the 25 new areas found during the previous year, and to a great extent can be attributed to the 26.5 per cent decline in wildcatting. The rate of new discoveries based on the 247 wildcats was 14.5 to I, which compares somewhat unfavorably with the 13.4 to I ratio obtained in 1940 (Table 5). Dry wildcats totaled 230. The proof of the prolific character of the South Texas area as a source of petroleum reservoirs is to be found in the fact that of the 1205 field or extension (semiwildcat) wells completed during the past year 61 opened production from new sands or found crude in formerly distillate-producing sands. The 1940 total of 1320 such wells accounted for 50 horizons that provided either new production or crude in distillate sands, and in this respect the 1941 rate of discovery shows to greater advantage, the ratios for new sands being 19.7 to I for 1941 and 26.4 to I for 1940. The 1205 field or semiwildcat wells completed in 1941 resulted in 926 oil or dis-

Jan 1, 1942

By İbrahim Çınar, Hakan Özşen

Mine workers in heavy and dangerous work are under several physical risk factors, for example temperature, humidity, noise, vibration, lighting and air velocity. Thermal comfort includes parameters such as air temperature, air humidity, air flow rate, radiant heat, metabolic rate and garment insulation. In this study, thermal comfort conditions were evaluated using thermal comfort indices defined as predicted mean vote (PMV) and predicted percentage dissatisfied (PPD) which were determined by measurements taken from an underground coal mine for approximately 100 days. Although the metabolic rate (light work) was kept at 2 met, it was found that predicted mean vote ranged between − 2.58 and 1.68. The predicted percentage dissatisfied index was found to reach 95%. According to the results, it can be seen that thermal comfort may have negative effects on occupational health and safety. The change in thermal comfort index values in the Soma Underground Coal Mine was investigated in detail and the reasons for the changes were determined. Furthermore, determining the optimal working environment for the mine workers was also an aim of this study.