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IC 8855 
 
 Bureau of Mines Information Circular/1981 
 
 Uranium Mine Ventilation Costs 
 
 By Robert C. Bates 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 
Information Circular 8855 
 
 Uranium Mine Ventilation Costs 
 
 By Robert C. Bates 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 James G. Watt, Secretary 
 
 BUREAU OF MINES 
 Robert C. Horton, Director 
 
As the Nation's principal conservation agency, the Department of the Interior 
 has responsibility for most of our nationally owned public lands and natural 
 resources. This includes fostering the wisest use of our land and water re- 
 sources, protecting our fish and wildlife, preserving the environmental and 
 cultural values of our national parks and historical places, and providing for 
 the enjoyment of life through outdoor recreation. The Department assesses 
 our energy and mineral resources and works to assure that their development is 
 in the best interests of all our people. The Department also has a major re- 
 sponsibility for American Indian reservation communities and for people who 
 live in Island Territories under U.S. administration. 
 
 ■ C/i/ 
 
 This publication has been cataloged as follows: 
 
 Bates, Robert C 
 
 Uranium mine ventilation costs. 
 
 (Information circular ; 8855) 
 
 Bibliography: p. 18. 
 
 Supt. of Docs, no.: I 28.27:8855. 
 
 1. Uranium mines and mining— Safety measures. 2. Mine ventila* 
 tion— Costs,, I. Title. II. Series: Information circular (United States. 
 Bureau of Mines) ; 8855. 
 
 TN295.U4 622s [338.2'3] 81-607862 AACR2 
 
 For sale by the Superintendent of Documents, U.S. Government Printing Office 
 
 Washington, D.C. 20402 
 
CONTENTS 
 
 Page 
 
 Abs tract 1 
 
 Introduction 1 
 
 Background 2 
 
 FRC staff report 2 
 
 RMC report 4 
 
 ADL study 7 
 
 Analysis 9 
 
 Applications 12 
 
 Cost of other control measures 16 
 
 Conclusions 17 
 
 References 18 
 
 ILLUSTRATIONS 
 
 1 . Cost per ton for ventilating uranium mines 10 
 
 2. Costs for ventilating uranium mines versus average annual exposure 
 
 with regression line 12 
 
 3. Projected radiation control cost for different Consumer Price 
 
 Indices and average annual exposures 14 
 
 4. Project radon-daughter control costs versus limiting miner exposure 
 
 WLM for several Consumer Price Index values 15 
 
 TABLES 
 
 1. Ventilation cost estimates, 11-mine study, 1965 3 
 
 2. Ventilation cost estimates, 3-mine study 3 
 
 3. Modified WL-control cost for three smaller mines 5 
 
 4. Radon-daughter control costs for five large uranium mines 6 
 
 5. Costs and radiation levels for various degrees of control 8 
 
 6. Federal Radiation Council Report 8 uranium mine ventilation cost 
 
 data converted to 1967 dollars per ton 9 
 
 7. Uranium mine ventilation cost data from Spencer converted to 
 
 1967 dollars per ton 10 
 
 8. Average ventilation costs and working place radon-daughter 
 
 concentrations 11 
 
 9. Consumer Price Index (1967 = 100) 13 
 
 10. Cost per ton at CPI = 250 (1980$) for several average WLM exposures 13 
 
 11. Cost per ton at CPI = 250 for several limiting miner exposures WLM. 15 
 
 12. Cost for radon control, from Kown 16 
 
URANIUM MINE VENTILATION COSTS 
 by 
 
 Robert C. Bates 1 
 
 ABSTRACT 
 
 This Bureau of Mines report converts published data on the cost of venti- 
 lating uranium mines to a common price base and analyzes these data to deter- 
 mine the cost per ton of uranium ore at various levels of radiation exposure 
 control. There appears to be an exponential increase of cost as the radiation 
 level is lowered. The 1967 base costs are extrapolated to present dollars, 
 and some cost comparisons are given for other radiation control measures. 
 
 INTRODUCTION 
 
 Since about 1950, the Bureau of Mines has been concerned about radon- 
 daughter concentrations in uranium mines. For a considerable time, this 
 interest was primarily oriented toward control by ventilation. Ventilation is 
 the most common airborne-radiation control measure used in uranium mines. 
 However, as the mines become deeper and larger, ventilation costs increase 
 tremendously and all available radiation control methods must be used to help 
 reduce the radiation hazards. 
 
 In 1973, the Bureau began investigating other methods to control 
 airborne-radiation levels and reduce ventilation requirements. Laboratory, 
 field, and theoretical evaluations were made of sealants, bulkheading, radon 
 removal, overpressurization, and radon-daughter removal. Costs were deter- 
 mined for several control techniques. For example, the cost for removing 
 radon from the air was found to be prohibitive (2), 2 
 
 In 1973, a Bureau study was performed of data from three reports (1_, 6^, 
 10 ) to estimate the cost of mine ventilation in terms that could be related 
 to control measure costs. These were the only reports that had seriously 
 discussed the cost of ventilating uranium mines. Since then, a study of 
 procedures for setting standards for radon-daughters has become available (5). 
 It evaluated the information in the three previous reports and, among other 
 
 Supervisory mining engineer, Spokane Research Center, Bureau of Mines, 
 
 Spokane, Wash. 
 2 Underlned numbers in parentheses refer to items in the list of references at 
 
 the end of this report. 
 
things, developed an exponential equation for ventilation costs. The informa- 
 tion given in the literature is not directly applicable for cost comparisons. 
 Therefore, the following text describes these three studies, describes the 
 analysis methods, compares the results with those of Cross (5) , projects the 
 costs for various radon-daughter exposure limits, and comments on some costs 
 of radon and radon-daughter control measures. 
 
 BACKGROUND 
 
 The three reports studied ^1_, 6_, 10 ) had been sponsored by the Federal 
 Radiation Council. The analysis base and philosophy for each were somewhat 
 different, thus making direct comparisons difficult. For example, three dif- 
 ferent parameters were used as the exposure bases for the three reports — aver- 
 age working level, 3 mine index, and "last man" working level. The mine 
 average WL might or might not be representative of the miners' exposure, 
 because extremely low values in haulageways or intake shafts can be averaged 
 with the supposedly higher ones in the stopes. A more representative value 
 for the person's exposure is the mine index, which uses the weighting of occu- 
 pancy time and the number of persons involved to calculate the average. The 
 third concept, the "last man" working level exposure, represents the highest 
 annual exposure recorded„for any underground personnel. The ventilation costs 
 are also given in two different ways, dollars per ton of ore produced and 
 dollars per pound of U3O8. The information available in these reports is 
 described briefly in the following paragraphs. 
 
 FRC Staff Report 
 
 A Federal Council (FRC) staff report (6) summarizes quite a bit of the 
 information available on the radiation problem in uranium mines. Although 
 various control methods were available, ventilation was the most important. 
 Since published information on ventilation costs was not available, the FRC 
 staff requested a number of uranium mining companies to carry out ventilation 
 cost studies. As they state (6_, p. 34), "These estimates are intended to 
 illustrate the general magnitude of cost in a few selected mines and are not 
 applicable to the industry as a whole." The studies were divided into two 
 groups. One covered 11 larger underground mines that accounted for more 
 than 20 pet of the U.S. uranium ore production, and the other group covered 
 3 mines that produced about 2 pet of the national total. 
 
 An exposure index was developed for the first group using time-weighted 
 average exposures that were weighted by the number of persons involved in each 
 of the worker categories. Estimates were made of the radon-daughter concen- 
 trations for minimal ventilation, and costs were tabulated for various levels 
 of radiation control. Ventilation and operating costs were projected over a 
 10-year period. Table 1 in their report is repeated here as table 1. 
 
 3 "Working level" (WL) means any combination of the short-lived radon daughters 
 in 1 liter of air that will result in the ultimate emission of 1.3 x 10 5 
 million electron volts (MeV) of alpha energy. 
 
TABLE 1. - Ventilation cost estimates, 11-mine study, 1965 (_6) 
 
 (Million dollars) 
 
 
 Investment 
 
 Operating cost 
 
 Total cost 
 
 Estimated mine 
 
 
 cost 
 
 (10-year est.) 
 
 ( 1 0-year s) 
 
 index WL 
 
 Past experience 
 
 3.9 
 
 7.9 
 
 11.8 
 
 l 2 
 
 Estimated ventilation 
 
 
 
 
 
 cost without radon 
 
 
 
 
 
 
 2.0 
 
 2.8 
 
 4.8 
 
 2 10 
 
 Additional cost for 
 
 
 radon control from 
 
 
 
 
 
 
 1.9 
 
 5.1 
 
 7.0 
 
 
 Estimated additional 
 
 
 
 
 
 cost to reduce from 
 
 
 
 
 
 
 1.5 
 
 6.0 
 
 7.5 
 
 1 
 
 Total cost to control 
 
 
 
 
 
 at 1 WL — 10 years.. 
 
 
 
 19.3 
 
 
 Composite mine index for 1965. 
 2 Estimate of what the average WL concentration would be with normal 
 ventilation practices. 
 
 The second group of three mines was considerably different from the 
 11 mines in geology, depth, extent of working, productive capacity, arrange- 
 ment of passageways, numbers of openings, and so on. The reporting of the 
 information was also different. Ventilation and operating costs were pro- 
 jected over a 6-year period instead of a 10-year period, and the working-level 
 values were reported as 1-year averages, rather than the mine index value used 
 for the 11-mine study. Table 2 of the FRC staff report (6) is given in its 
 entirety as table 2 in this report. 
 
 TABLE 2. - Ventilation cost estimates, 3-mine study (_6) 
 
 (Thousand dollars) 
 
 
 Investment 
 cost 
 
 Oper. cost 
 (6-year est. ) 
 
 Total cost 
 (6-years) 
 
 Average 
 concentration, 
 WL 
 
 Past experience: 
 
 361 
 
 321 
 
 75 
 
 120 
 85 
 50 
 
 481 
 406 
 125 
 
 x 1.4 
 
 Mine B 
 
 H.5 
 
 
 H.5 
 
 
 757 
 
 63 
 
 66 
 
 6 
 
 255 
 
 21 
 
 18 
 
 4 
 
 1,012 
 
 84 
 84 
 10 
 
 
 Estimated for case of 
 minimum ventilation: 
 
 
 Mine B 
 
 2 5-20 
 
 
 
 
 135 
 
 43 
 
 178 
 
 
 1 Average WL concentrations in 1965. 
 2 Estimate of what the average WL concentrations would be with normal 
 ventilation practices. 
 
RMC Report 
 
 Spencer (10) of the Resource Management Corp. (RMC) examined a number of 
 items, including costs, associated with the control of radon daughters in ura- 
 nium mines. Although literature was collected, much of the information came 
 from personal discussions with knowledgeable government and industry people. 
 From these discussions, Spencer decided to limit their studies to the Colorado 
 Plateau region (Uravan mineral belt and Ambrosia Lake). Their evaluations 
 also led RMC to the conclusion that only two approaches, historical and mod- 
 eling, appeared usable for cost estimating. Historical data could provide a 
 relationship between cost and working levels from which they could extrapolate 
 to the average mine with a 0.3-WL concentration. Although this technique has 
 a number of inadequacies stemming from the wide range in the characteristics 
 of the mining operations supplying the data, it was possible for RMC to 
 arrive at some figures in a very short time. The modeling approach, because 
 of the complexity of the mining process itself, was too complex for the short 
 time period of the study. Therefore, data were requested and received from 
 eight operating mines (three small and five large) for 3 years of production, 
 1966, 1967, and 1968. 
 
 The three small mines had relatively small output tonnages but fairly 
 large underground areas* Costs included supplies, labor, power, air courses, 
 and capital investments. Capital and ventilation costs for drifts and raises 
 were amortized over a 5-year period. The capital expenditures were reportedly 
 amortized over a 10-year period. A summary of their data is given in table 3. 
 The radon-daughter concentrations are given as average working levels. 
 
TABLE 3. - Modified WL-control cost for three smaller mines (10) 
 
 Mine and year 
 
 Ore output, 
 10 3 tons 
 
 Average con- 
 centration, WL 
 
 Cost per ton 
 of ore 1 
 
 Modified cost 
 
 per ton of 
 
 ore 2 
 
 Mine A: 3 
 
 1966 
 
 12 
 9.4 
 7.7 
 
 H.O 
 3.0 
 2.2 
 
 34.1 
 36.2 
 29.3 
 
 16.7 
 16.2 
 13.1 
 
 2.2 
 2.1 
 
 .7 
 
 3.1 
 
 2.1 
 
 .6 
 
 1.3 
 1.3 
 
 .5 
 
 1.66 
 
 1.50 
 
 .55 
 
 $0.33 
 
 1.10 
 
 .51 
 
 .47 
 
 1.38 
 
 .90 
 
 .21 
 
 .47 
 
 2.19 
 
 .26 
 
 .65 
 
 1.79 
 
 $0.28 
 
 1967 
 
 .64 
 
 1968 
 
 .57 
 
 Mine B: 3 
 
 1966 
 
 .43 
 
 1967 
 
 1.08 
 
 1968 
 
 .89 
 
 Mine C : 3 
 
 1966 
 
 .20 
 
 1967 
 
 .44 
 
 1968 
 
 1.47 
 
 Average: 5 
 
 1966 
 
 .24 
 
 1967 
 
 .52 
 
 
 1.26 
 
 Capital expenditure written off over 10 years; some totals in RMC report (10) 
 
 appeared to be wrong, so recalculated values were used. 
 2 Cost of air courses amortized over 5 years. 
 3 Data are for 1st half of year. 
 
 4 1966 output of mine B was not available; assumed by extrapolation, 
 individual mine data averaged by tonnage ore output. 
 
 The owners of the five larger mines reported total capital assets in the 
 original data, but Spencer used only the incremental capital expenditures for 
 the period of interest. Therefore, certain capital costs did not contribute 
 to the 1966-68 working level reductions. However, the improvements in concen- 
 tration are shown as functions of new capital investments and increased oper- 
 ating and maintenance costs. The working level averages given in their tables 
 are not based on personal exposures but are simple arithmetic averages of per- 
 iodic readings taken by the mine operator in the occupied areas of the mine. 
 In one sense, since most of the underground workers are in areas of higher 
 radon concentration, the average exposure might be higher than the data indi- 
 cate. Further analysis (based on some additional information supplied by the 
 owners) indicated that, for the period studied, average exposures and aver- 
 age working levels were equal. A summary of the five-mine data is given in 
 table 4. 
 
TABLE 4. - Radon-daughter control costs for five large uranium mines (10) 
 
 Mine and year 
 
 Mine average 
 WL's 1 
 
 Ore output, 1 
 10 3 tons 
 
 Total costs 
 per ton 2 
 
 Mine D: 
 
 1966 
 
 2.0 
 .8 
 .4 
 
 2.2 
 
 1.1 
 
 .5 
 
 1.6 
 
 1.4 
 
 .5 
 
 2.3 
 
 1.3 
 
 .7 
 
 1.5 
 
 1.1 
 
 .6 
 
 2.03 
 
 1.18 
 
 .55 
 
 132 
 
 115 
 
 79 
 
 237 
 278 
 154 
 
 119 
 
 184 
 104 
 
 212 
 276 
 150 
 
 84 
 
 154 
 
 78 
 
 157 
 
 201 
 113 
 
 $0.76 
 .86 
 
 1967 
 
 1968 3 
 
 .92 
 
 Mine E: 
 
 1966 
 
 .57 
 
 1967 
 
 .57 
 
 1968 3 
 
 .71 
 
 Mine F: 
 
 1966 
 
 .67 
 
 1967 
 
 .87 
 
 1968 3 
 
 .84 
 
 Mine G: 
 
 1966 
 
 .55 
 
 1967 * 
 
 .66 
 
 1968 3 
 
 .88 
 
 Mine H: 
 
 1966 
 
 .64 
 
 1967 
 
 .51 
 
 1968 3 
 
 .74 
 
 Average: 4 
 
 1966 
 
 .62 
 
 1967 
 
 .67 
 
 
 .81 
 
 ^Original WL data, given for each half of each year, were weighted by ore 
 
 output for each 6-month period to arrive at these yearly averages. 
 2 Includes new capital costs at 10-yr writeoff. 
 3 First half of 1968 only. 
 ^Some values recalculated from published table (10, table 3). 
 
 The mathematical analysis, cost versus working level, of the three-mine 
 data yielded a linear equation, and that of the five-mine data an exponential 
 equation. Their calculations indicate that to keep the highest exposure under 
 0.3 WL, the mine average must be 0.15 WL. Extrapolating to this low level, 
 they estimated a cost of approximately $1.05 per ton. Thompkins (11) took 
 exception to this calculation and drew another curve through their data, indi- 
 cating that it would be impossible to achieve less than a 0.5-WL average, 
 regardless of how much money was spent on ventilation. 
 
ADL Study 
 
 The study by Arthur D. Little, Inc. (ADL) for the Federal Radiation Coun- 
 cil (1) is the most thorough evaluation of costs relative to radon-daughter 
 control that is available. ADL personnel selected a sample of 26 underground 
 uranium mines that would represent the underground uranium mining industry. 
 In addition, they covered the more important producing regions, including 
 large and small mines, old and new mines, and mines with high and low emana- 
 tion rates. For early 1970, at the time of radon-daughter sampling, the 
 26 mines represented 29 pet of the mines, 81 pet of the production, and 88 pet 
 of the underground employees in the United States. 
 
 The information supplied by each mine operator included working levels 
 and costs. Some operators furnished data on percentages of underground miners 
 receiving exposures in various working-level-month (WLM) 4 ranges. They also 
 supplied detailed mine maps showing the location of ventilation holes, fans, 
 secondary air bags, measured working levels, and airflow at various points in 
 each mine. The measurements recorded were taken in March 1970. From all of 
 the working-level data, ADL personnel were able to calculate three figures to 
 characterize the situation at each mine: 
 
 1. Mine working-place average working level, which is the average of all 
 working level readings reported in working places and access ways on the mea- 
 surement day. 
 
 2. Maximum working level, which is the highest value reported in any 
 working place on the evaluation date. 
 
 3. The "last man" working-level-month, which is the highest 1969 expo- 
 sure recorded for an individual. The costs for ventilation and radiation con- 
 trol included fan power, maintenance, heating, and labor for ventilation and 
 sampling, as well as capital costs for ventilation holes and other ventilation 
 equipment . 
 
 After gathering the baseline information, ADL had a team of mining, 
 ventilation, and radiation control experts study each mine to establish the 
 changes that would be necessary to assure that a reading of 0.3 or 0.6 WL 
 would not be exceeded in any working or travel area. These would then equate 
 4 or 8 "last man" WLM exposures. A design was developed for each mine to 
 assure satisfying the 4 and 8 WLM per year standards. The incremental costs 
 were calculated using standard unit costs. New investments such as additional 
 drill holes, fans, bulkheads, and air heaters were included. The additional 
 operating costs for power, labor, fuel, and supplies were also considered. 
 Amortization for new capital items was done against 1 year's ore production 
 from the mine. This procedure does result in higher costs than would be 
 expected if the amortization was done more on a basis of the total ore 
 reserves, if these had been known. Data extracted from the ADL report are 
 given in table 5. 
 
 ^Inhalation of air containing a radon-daughter concentration of 1 WL for 
 173 hr results in an exposure of 1 WLM. 
 
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ANALYSIS 
 
 Since these studies spanned a 5-year period, the cost data should be put 
 
 on a common base before analysis. The Consumer Price Index (CPI), also known 
 
 as Cost of Living Index, was used to change all costs to 1967 dollars (1967$); 
 hence CPI = 100 in 1967. 
 
 The Federal Radiation Council data (6) first required a calculation of 
 the estimated tonnage for the mines over a 10-year period. In 1965, the 
 11 mines (table 1) produced over 20 pet of the total U.S. production, 5 which, 
 at exactly 20 pet, amounts to 872,523 tons of ore. Therefore, the 10-year 
 production is over 8.73 million tons. Table 6 gives the ventilation control 
 costs converted to dollars per ton. The three small mines produced approxi- 
 mately 87,252 tons of uranium ore in 1965, or approximately 0.52 million tons 
 in the 6-year analysis period (table 6). The working level month figures and 
 1967 dollars per ton are plotted in figure 1. 
 
 TABLE 6. - Federal Radiation Council Report 8 (_6) uranium mine ventilation 
 
 cost data converted to 1967 dollars per ton 
 
 Item 
 
 Total cost, 
 millions 
 
 Cost per ton 
 
 Mine index 
 or average WL 
 
 WLM 
 
 
 In 1965$ 
 
 In 1967$ 
 
 
 11-mine study (10-yr): 
 Minimum ventilation. 
 
 3-mine study (6-yr): 
 Minimum ventilation. 
 Control to 1.5 WL... 
 
 $4.8 
 11.8 
 19.3 
 
 .18 
 1.01 
 
 $0.55 
 1.35 
 2.21 
 
 .34 
 1.93 
 
 $0.58 
 1.43 
 2.34 
 
 .36 
 
 2.04 
 
 Ho 
 
 2 
 
 1 
 
 ^-20 
 31.5 
 
 120 
 24 
 12 
 
 2 150 
 18 
 
 Estimate of average WL with normal metal mine ventilation practice. 
 2 Midrange, 12.5 WL, used to calculate WLM. 
 3 Average concentration. 
 
 It is assumed that the costs supplied to Spencer (10) by the mine owners 
 are CPI-corrected for each year during 1966-68. Table 7 summarizes the data 
 and the conversions to 1967 dollars (1967$). These data and the production- 
 weighted averages for all eight mines are also plotted in figure 1. As 
 expected, because of the much greater tonnage, the weighted average is very 
 close to the values for the five larger mines. Cross (5) pointed out that 
 Spencer (10) neglected the succeeding years' equipment amortization and return 
 on investment. This may have resulted in a cost understatement of 20 percent; 
 the corrected data are also plotted in figure 1. 
 
 5 Total U.S. production in 1965 was 4,362,614 tons (3). 
 
10 
 
 TABLE 7. - Uranium mine ventilation cost data from Spencer (10) , 
 
 converted 1967 dollars per ton 
 
 Item 
 
 Cost per ton 
 
 Cost, 1967 dollars 
 per ton 
 
 Average 
 WL 
 
 WLM 
 
 Three smaller mines: 
 
 1966 
 
 $0.24 
 
 .52 
 
 1.26 
 
 .62 
 .67 
 .81 
 
 $0.25 
 
 .52 
 
 1.21 
 
 .64 
 .67 
 .78 
 
 1.66 
 
 1.50 
 
 .55 
 
 2.03 
 
 1.18 
 
 .55 
 
 20 
 
 1967 
 
 18 
 
 1968 
 
 6.6 
 
 Five larger mines: 
 
 1966 
 
 24 
 
 1967 
 
 14 
 
 
 6.6 
 
 10. 
 9 
 8. 
 
 7. 
 6 
 
 5. 
 
 4. 
 
 c 
 
 2 3. 
 
 r>» 
 <o 
 o> 2. 
 
 V) 
 
 o 
 o 
 
 z 
 o 
 
 I. 
 
 .9 
 .8 
 .7 
 
 6 _ 
 
 .3 _ 
 
 X 
 
 + 
 8 
 
 + 
 
 + 
 
 s 
 
 J Ill 
 
 KEY 
 O 1 1-mine study. FRC 
 
 V 3-mine study, FRC 
 
 O 5 larger mines, RMC 
 
 x 3 smaller mines, RMC 
 
 Weighted average of RMC data 
 
 D 
 
 + 
 
 RMC weighted average 
 corrected for 20% cost error 
 by Cross (5) 
 
 H Average cost and WLM data, ADL 
 
 A Estimated weighted average of 
 ADL data 
 
 10. 100. 
 
 AVERAGE ANNUAL EXPOSURE. WLM 
 
 FIGURE 1. - Cost per ton for ventilating uranium mines. 
 
 1,000. 
 
11 
 
 The ADL study (1) had as its sole purpose to derive the total costs and 
 impacts of decreasing the allowed radon-daughter exposure. The data for all 
 26 mines are given in table 5. There is considerable scatter in the informa- 
 tion; therefore, care was taken to arrive at reasonable averages. The authors 
 of the ADL report provided production-weighted incremental costs to arrive at 
 8 and 4 WLM exposures (table 5), but two key items are missing from the ADL 
 survey — "present weighted average cost per ton" and "present average working 
 level." These are estimated in two ways, arithmetic averages and using the 
 observed differences in the average value and the ADL production-weighted 
 average costs. These are given in table 8, and plotted in figure 1. 
 
 TABLE 8. - Average ventilation costs and working place 
 radon-daughter concentrations 
 
 
 Cost per ton, 
 
 Cost per ton, 
 
 
 
 
 1970$ 
 
 1967$ 
 
 Average WL 
 
 
 Item 
 
 Using 
 
 Using 
 
 Using 
 
 Using 
 
 Average WLM 
 
 
 table 5 
 
 table 5 
 
 table 5 
 
 table 5 
 
 
 
 
 averages 
 
 weighted 
 averages 
 
 averages 
 
 weighted 
 averages 
 
 
 
 Present conditions 
 
 1.88 
 
 1.03 
 
 1.66 
 
 0.91 
 
 0.487 
 
 5.8 
 
 Last man = 8 WLM. . 
 
 2.69 
 
 1.53 
 
 2.38 
 
 1.35 
 
 1 .451 
 
 5.4 
 
 Last man = 4 WLM.. 
 
 5.19 
 
 2.76 
 
 4.59 
 
 2.44 
 
 !.226 
 
 2.7 
 
 *Ratio calculated from table 5 averages used to calculate average WL, 
 
 The best values from the three studies are plotted together in figure 2, 
 and a least-squares line, calculated in logarithmic space, has been drawn 
 through the data. The equation for this line is 
 
 1967$/ton = 3.134 (WLM)" - 3715 , 
 with a correlation coefficient, R = -0.75. 
 
 (1) 
 
 The 95-percent confidence limit on the expected value of the mean is, in 
 1967$/ton, approximately $1.10±$0.07, and for a particular value of the mean 
 it is $1.10±$0.32. An equation was also calculated using the average val- 
 ues. This equation has a steeper slope and larger intercept: 
 
 and 
 
 1967$/ton = 4.616 (WLM)" - h8 19 , 
 R = -0.77. 
 
 (2) 
 
 In both cases, the fit is significant at the 0.01 level (99-percentile) , but 
 the first equation is used in the remainder of this paper since it includes 
 the corrections that are considered necessary. The exponential model 
 developed by Cross (_5) from the individual mine data is given in cents per 
 pound U3O8 (1969 dollars) versus average annual exposure. By converting their 
 equation to dollars per ton (assuming 0.22 pet U3O3 ore grade) and 1967 
 dollars, it becomes 
 
 1967$/ton = 3.979 (12WL)" - 63 . 
 
 (3) 
 
12 
 
 CO 
 
 O 
 O 
 
 z 
 o 
 
 < 
 
 _l 
 
 t- 
 z 
 
 LU 
 
 > 
 
 _l 
 < 
 
 I- 
 
 o 
 
 r 4. 
 
 2 
 
 I 
 
 — 
 
 
 
 
 
 
 KEY 
 
 — 
 
 
 
 
 
 
 O 1 1-mine study. FRC 
 
 — 
 
 
 
 
 
 
 V 3-mine study , FRC 
 
 "^ 
 
 
 
 
 
 
 + Weighted average of RMC 
 
 
 **^^«^ A 
 
 
 o 
 
 
 
 data corrected for 20% error 
 by Cross (5) 
 
 A ADL data with corrected cost 
 and WLM 
 
 
 
 A 
 
 
 V 
 
 o 
 
 ,1967$/ton = 3.134 (WLM) ~° 3715 
 
 — 
 
 
 + 
 
 A 
 
 
 
 / R = -0.75 
 
 — 
 
 
 
 + 
 
 
 + 
 
 
 — 
 
 
 
 
 
 
 ^"""^^O 
 
 — 
 
 
 
 
 
 
 V **^^^^ 
 
 
 1 1 
 
 Mill 
 
 II 
 
 I 
 
 1 
 
 I I I I III I I I I I I II 
 
 3 _ 
 
 I. 
 
 10. 100. 
 
 AVERAGE ANNUAL EXPOSURE. WLM 
 
 FIGURE 2. - Costs for ventilating uranium mines versus average annual exposure with regression line. 
 
 1,000. 
 
 This equation has a larger intercept and a much steeper slope than the 
 equation developed from weighted average costs and working levels. Higher 
 cost estimates for control to 1- to 2-WLM annual exposures results when this 
 equation is used. 
 
 APPLICATIONS 
 
 Equation 1 can be used with some limitation to estimate the industry 
 average cost for ventilating uranium mines at any desired average working 
 level at any consumer price index and provide comparisons with other radiation 
 control costs. 
 
13 
 
 The inflationary rise in the Consumer Price Index since 1965 is shown in 
 table 9. Since the data used in the analysis were converted to the 1967 base 
 CPI, it is a simple matter to multiply the calculated cost per ton by the new 
 CPI divided by 100, as follows: 
 
 $/ton = 3.134 -y|| (WLM)-°' 3715 , 
 
 = 0.03134 CPI(WLM)-°» 3715 . 
 An example for CPI = 250 (1980$) is given in table 10 and figure 3. 
 TABLE 9. - Consumer Price Index (based on 1967 = 100) 
 
 1965.... 
 
 94.5 
 
 1972 
 
 125.3 
 
 1979 
 
 217.6 
 
 1966 
 
 97.2 
 
 1973.... 
 
 133.1 
 
 1980.... 
 
 246.9 
 
 1967 
 
 100.0 
 
 1974 
 
 147.7 
 
 1981: 
 
 
 1968.... 
 
 104.2 
 
 1975 
 
 161.2 
 
 Jan. . . 
 
 260.7 
 
 1969 
 
 109.8 
 
 1976 
 
 170.4 
 
 Feb... 
 
 263.5 
 
 1970 
 
 116.3 
 
 1977 
 
 181.5 
 
 Mar. .. 
 
 265.2 
 
 1971.... 
 
 121.3 
 
 1978 
 
 195.3 
 
 Apr . . . 
 
 266.8 
 
 TABLE 10. - Cost per ton at CPI = 250 (1980$) 
 for several average WLM exposures 
 
 Average 
 
 WLM 
 
 Cost per ton 
 
 
 At CPI = 100 
 
 At CPI = 250 
 
 4 
 
 
 $1.87 
 
 $4.68 
 
 2 
 
 
 2.42 
 
 6.06 
 
 1 
 
 
 3.13 
 
 7.84 
 
 .7 
 
 
 3.58 
 
 8.95 
 
 (4) 
 
14 
 
 30 
 
 w 
 
 i- 
 w 
 O 
 o 
 
 _l 
 
 o 
 
 IX 
 
 H 
 Z 
 
 o 
 o 
 
 z 
 o 
 
 20. 
 
 j^^^s 
 
 
 
 
 
 10. 
 9. 
 8. 
 7. 
 
 
 
 
 v — L 
 
 
 
 6. 
 5. 
 
 
 
 
 
 
 
 
 4. 
 
 3. 
 
 2. 
 
 0.7 WLM 
 1 
 
 " last 
 WLM " 
 
 man" 
 last n 
 2 WL 
 
 I 
 
 lan" 
 M * \i 
 
 ist 
 
 
 
 
 
 4 WLM * last man 
 
 
 1. 
 .9 
 .8 
 
 
 
 
 
 
 .7 
 
 
 
 
 
 
 .6 
 
 
 
 
 
 
 .5 
 
 
 
 
 
 
 .4 
 
 
 
 * 
 
 
 
 .3 
 
 
 
 
 
 
 .2 
 .1 
 
 
 I I 
 
 I I I I I 
 
 II I 
 
 i i 1 1 1 mi mi 
 
 I. 10. 
 
 AVERAGE ANNUAL EXPOSURE. WLM 
 
 I00. 
 
 FIGURE 3. 
 
 Projected radiation control cost for different Consumer Price Indices and 
 average annual exposure. 
 
 At this point, the "last man" exposure should be introduced. If an 
 average working level exposure of 4 WLM is maintained, some miners will be 
 overexposed. Therefore, we should make the projections based on limiting the 
 maximum exposure. Information in the ADL report (1) indicated a factor of 
 1.478 between the average working-level-month exposure and the "last man" 
 exposure. After incorporating both "last man" exposure and consumer price 
 index, equation 1 becomes — 
 
 DPT = 0.03624 CPI (LME) -0 ' 3715 , 
 
 where DPT = dollars per ton corrected for CPI, 
 
 and LME = limiting miner exposure (the highest annual 
 
 exposure received by an underground employee). 
 
 (5) 
 
15 
 
 Table 11 gives an example of several limiting exposures at a CPI of 250. 
 information, along with several other CPI's, is shown in figure 4. 
 
 TABLE 11. - Cost per ton at CPI = 250 for several 
 limiting miner exposures WLM 
 
 This 
 
 Limiting miner 
 
 expo 
 
 sure, 
 
 Average 
 
 WLM 
 
 Cost per ton 
 
 WLM 
 
 
 
 
 
 at CPI = 250 
 
 4 
 
 
 
 2.71 
 
 
 $5.41 
 
 2 
 
 
 
 1.35 
 
 
 7.00 
 
 1 
 
 
 
 .68 
 
 
 9.05 
 
 .7 
 
 
 
 .47 
 
 
 10.34 
 
 c 
 o 
 
 w 
 
 w 
 o 
 o 
 
 _l 
 
 o 
 a. 
 
 t- 
 z 
 o 
 o 
 
 30. 
 
 20. 
 
 10. 
 9. 
 8. 
 7. 
 
 6. 
 5. 
 4. 
 
 1. 
 
 
 
 
 
 
 
 — ^^^ 
 
 
 o^\^ 
 
 — 
 
 
 ^^^\\^ 
 
 — 
 
 
 ^^T^\^\^^^ 
 
 — 
 
 
 
 I 
 
 I I I I MM 
 
 I I I I I Mil I II 
 
 .1 
 
 1. 10. 
 
 LIMITING MINER EXPOSURE, WLM 
 
 100. 
 
 FIGURE 4. - Project radon-daughter control costs versus limiting miner exposure WLM 
 for several Consumer Price Index values. 
 
16 
 
 In looking at these projected costs for radiation control in uranium 
 mines, it is apparent that they are significant. The underground uranium ore 
 production in 1979 was approximately 6 million tons (8). Therefore, the esti- 
 mated present cost is over $32 million per year if the industry is truly main- 
 taining 4 WLM. If the limit is reduced to 2 WLM, the estimated total cost is 
 $42 million; for a 1-WLM limit, it is $54 million, and for a 0.7-WLM limit, it 
 is $62 million. Clearly, any change in permitted exposure levels can have a 
 serious economic impact on mining costs. Also, as mines become deeper and 
 larger than the mines in the 1965-70 base period, the total cost for ventila- 
 tion is going to increase significantly, unless other control measures, are 
 used to cut the ventilation requirements. 
 
 COST OF OTHER CONTROL MEASURES 
 
 Even with the present cost, we should be looking at all of the other 
 available control measures. In recent years there has been an attempt by the 
 Bureau of Mines and others to arrive at cost factors for other control tech- 
 niques. The U.S. Environmental Protection Agency (EPA) sponsored a 2-month 
 study that resulted in a report by Kown (9). This study considered the mine 
 as a whole and its total production of radon, 8.86 Ci/day. Some of the radon 
 reductions and costs given by Kown (9) are shown in table 12. Other control 
 measures such as mine pressurization, the use of highly reactive chemical 
 oxidants, and specialized mining techniques were discussed, but costs were 
 not calculated. 
 
 TABLE 12. - Costs for radon control from Kown (9) 
 
 Control measure 
 
 Radon reduction, 
 Ci/day 
 
 Cost per 
 ton 
 
 Activated charcoal 
 with bulkheading.... 
 
 1.01 
 2.95 
 
 3.01 
 
 $1.45 
 .34 
 
 4.32 
 
 Cost figures reported by the Bureau of Mines are usually for single 
 installations. For example, the materials cost of an 8- by 14-foot bulkhead 
 was $186 to $295 (_7)» Radon barrier sealant costs per square foot have been 
 $0.30 to $1.19 ($0.46 to $1.84 in 1980 dollars) (4). The most expensive coat- 
 ing system was the least satisfactory material because it contained chopped 
 fiberglass. Field tests of sealants showed radon-stopping power of up to 
 7 5 percent; therefore, they can reduce the amount of ventilation needed to 
 control the radon-daughter concentrations to a given level. 
 
 Cost figures like these can be compared with the cost for ventilation 
 control. To accomplish this, the cost of a control measure must be expressed 
 in the same units as ventilation costs — dollars per ton — and the effect of the 
 new control measure must be defined. For example, cost per square foot is the 
 most convenient for sealant coatings, and this can be related to a cost per 
 ton by considering the surface area remaining in the excavation of typical 
 drifts. In a 6- by 7-foot opening, about 8.2 square feet of rock is exposed 
 around the periphery for each ton of rock removed; for a 12- by 14-foot 
 
17 
 
 drift, about 4.1 square feet of surface is left per ton of rock removed. 
 Therefore, sealant coatings cost about $2 or $3 per ton (1980). This is con- 
 siderably less than the estimated $5.43 per ton for present radon-daughter 
 control. 
 
 CONCLUSIONS 
 
 The available radiation control cost information has been analyzed and 
 yielded the equation: Cost, 1967$/ton = 3.134 (WLM)~ ' 3715 . Combining limit- 
 ing miner exposure, LME, and consumer price index, CPI, the dollars per ton 
 (DPT) can be estimated from DPT = 0.03624 CPI (LME)" * 3715 . The 1967 cost per 
 ton for a number of average and limiting miner working-level-month exposures 
 has been calculated and converted to a 1980 CPI value. At a LME of 4 WLM, the 
 projected cost per ton for radiation control is $5.41. If the LME is reduced 
 to 0.7 WLM, the projected cost per ton is $10.34. These values are only 
 applicable to radiation control in U.S. sandstone-type mines. Considering 
 the projected costs per ton, any reasonable technology should be used in the 
 control of radon and radon-daughters. 
 
 ma 
 
18 
 
 REFERENCES 
 
 1. Arthur D. Little, Inc. An Assessment of the Ecomonic Effects of 
 
 Radiation Exposure Standards for Uranium Miners. Rept. to the Fed. 
 Radiation Council, November 1970, 2d ed. , 250 pp. 
 
 2. . Advanced Techniques for Radon Gas Removal. BuMines Open File 
 
 Rept. 60-75, May 1975, 209 pp. ; available for reference at BuMines 
 facilities in Pittsburgh, Pa., Denver, Colo., Spokane, Wash., and Twin 
 Cities, Minn.; at the National Library for Natural Resources, 
 
 U.S. Dept. of the Interior, Washington, D.C.; and at the Dept. of 
 Energy facility in Morgantown, W. Va. ; available from National Tech- 
 nical Information Service, Springfield, Va. , PB 243 898; BuMines 
 contract H0230022. 
 
 3. Baroch, C. T. Uranium. Ch. in BuMines Minerals Yearbook 1965. V. 1. 
 
 Metals and Minerals (Except Fuels), pp. 973-991. 
 
 4. Bates, R.C., and J. C. Franklin. U.S. Bureau of Mines Radiation 
 
 Control Research. Proc. Conf. on Uranium Min. Technol. , Reno, Nev. , 
 Apr. 25-29, 1977, 32" pp. 
 
 5. Cross, F. T. , C. H. Bloomster, P. L. Hendrickson, and I. C. Nelson. 
 
 Evaluation of Methods for Setting Occupational Health Standards for 
 Uranium Mines. Nat. Inst, for Occupational Safety and Health, NIOSH 
 Rept. 72-2, 1974, 237 pp.; available from Nat. Tech. Inf. Service, 
 Springfield, Va. , PB 237 744; NIOSH contract HSM-99-72-135, 
 Battelle-Pacif ic Northwest Laboratories. 
 
 6. Federal Radiation Council. Guidance for the Control of Radiation Hazards 
 
 in Uranium Mining. FRC Rept. 8, rev. September 1967, 60 pp. 
 
 7. Franklin, J. C. , C. S. Musulin, and D. W. Thebeau. Research on Bulkheads 
 
 for Radon Control in Mines. Proc. Update on Uranium Min. Technol. , 
 Reno, Nev., Nov. 13-17, 1978, 11 pp. 
 
 8. Klemenic, J. Production Capability. Proc. Update on Uranium Min. 
 
 Technol., Reno, Nev., Nov. 13-17, 1978, 30 pp. 
 
 9. Kown, B. T. , V. C. Van der Mast, and K. L. Ludwig. Technical Assessment 
 
 of Radon 222, Control Technology for Underground Uranium Mines. 
 Bechtel National, Inc., San Francisco, Calif. Task 9, 1979, 61 pp. 
 
 10. Spencer, N. , L. Spittel, T. Towles, and G. Lady. Control of Radiation 
 
 Exposure in Uranium Mines: A Cost and Economic Analysis. Resource 
 Management Corp., Rept. UR-42, prepared for the Federal Radiation 
 Council, November 1968, 66 pp. 
 
 11. Thompkins, R. W. Radiation Control in North American Mines and Their 
 
 Effects on Mining Costs. Proc. 7th Internat. Min. Cong., Bucharest, 
 Romania, September 1972, pp. 1-11. 
 
 « U S. GOVERNMENT PRINTING OFFICE : 1981 358-313/7175 
 
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