**DEPARTMENT OF LABOR**

Mine Safety and Health Administration

____________________________________________________________

30 CFR Parts 57, 72 and 75

RIN 1219-AA74; 1219-AB11

Diesel Particulate Matter Exposure of Underground Coal and Metal and Nonmetal Miners

**AGENCY:**Mine Safety and Health Administration (MSHA), Labor.

**ACTION:**Proposed rules; corrections.

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**SUMMARY:**This document corrects errors in the preamble discussions to the proposed rule on diesel particulate matter exposure of underground coal miners, and the proposed rule on diesel particulate matter exposure of underground metal and nonmetal miners. Specifically, this document corrects errors in the Diesel Emission Control Estimator formula in the proposed Appendix to Part V of both preambles; and corrects certain titles in proposed Figures V-1 through V-5 of

[[Page 36827]]

the metal and nonmetal preamble, and proposed Figure V-5 of the coal preamble.

**DATES:**Written comments on these clarifications and corrections must be submitted on or before July 26, 1999.

**ADDRESSES:**You may use mail, facsimile (fax), or electronic mail to send your comments to MSHA. Clearly identify comments as such and send them--

(1) By mail to Carol J. Jones, Acting Director, Office of Standards, Regulations, and Variances, MSHA, 4015 Wilson Boulevard, Room 631, Arlington, VA 22203;

(2) By fax to MSHA, Office of Standards, Regulations, and Variances, 703-235-5551; or

(3) By electronic mail to zzMSHA-Comments@dol.gov.

**FOR FURTHER INFORMATION CONTACT:**Carol J. Jones, Acting Director; Office of Standards, Regulations, and Variances; MSHA; 703-235-1910.

**SUPPLEMENTARY INFORMATION:**On April 9, 1998 (63 FR 17492), MSHA published a proposed rule addressing diesel particulate matter exposure of underground coal miners. On October 29, 1998 (63 FR 58104), the agency published a proposed rule addressing diesel particulate matter exposure of underground metal and nonmetal miners. These proposals seek to reduce the risks to underground coal and metal and nonmetal miners, respectively, of serious health hazards associated with exposure to high concentrations of diesel particulate matter (dpm). DPM is a very small particle in diesel exhaust. Underground miners are exposed to far higher concentrations of this fine particulate than any other group of workers.

After publication of both proposed rules, MSHA realized that the Diesel Emission Control Estimator formula in Appendix to Part V: Diesel Emission Control Estimator was incorrect. The formula did not contain the unit conversion factors of 60 minutes/hour and 1000 µg/mg. Also, the formula did not contain the "Ts'' unit factor, which represents the total shift length, hours. However, the spreadsheet supplied by MSHA performs the calculations correctly because it contains these units.

This document corrects these errors by including the conversion factors, and the "Ts'' unit in the Diesel Emission Control Estimator formula. Additionally, the Agency is taking this opportunity to correct certain titles in proposed Figures V-1 through V-5 of the metal and nonmetal preamble, and proposed Figure V-5 of the coal preamble. These titles are being corrected because the specific units of measurement are misstated. Below are these corrections.

**I. Corrections to Proposed Rule on Diesel Particulate Matter Exposure of Underground Metal and Nonmetal Miners (63 FR 58104)**

[Figure V-1]:

1. On page 58198, Figure V-1, section 1, line 1, "MEASURED OR ESTIMATED IN MINE DP EXPOSURE (µg/m

^{3})'' should read "MEASURED OR ESTIMATED DPM CONCENTRATION (µg/m

^{3})''.

2. On page 58198, Figure V-1, section 2, line 18, "AVERAGE TOTAL SHIFT PARTICULATE OUTPUT (gm)'' should read "AVERAGE, TOTAL SHIFT, ENGINE EMISSION RATE (gm/hp-hr)''.

[Figure V-2]:

1. On page 58199, Figure V-2, section 1, line 1, "MEASURED OR ESTIMATED IN MINE DP EXPOSURE (µg/m

^{3})'' should read "MEASURED OR ESTIMATED DPM CONCENTRATION (µg/m

^{3})''.

2. On page 58199, Figure V-2, section 2, line 18, "AVERAGE TOTAL SHIFT PARTICULATE OUTPUT (gm)'' should read "AVERAGE, TOTAL SHIFT, ENGINE EMISSION RATE (gm/hp-hr)''.

[Figure V-3]:

1. On page 58200, Figure V-3, section 1, line 1, "MEASURED OR ESTIMATED IN MINE DP EXPOSURE (µg/m

^{3})'' should read "MEASURED OR ESTIMATED DPM CONCENTRATION (µg/m

^{3})''.

2. On page 58200, Figure V-3, section 2, line 18, "AVERAGE TOTAL SHIFT PARTICULATE OUTPUT (gm)'' should read "AVERAGE, TOTAL SHIFT, ENGINE EMISSION RATE (gm/hp-hr)''.

[Figure V-4:]

1. On page 58201, Figure V-4, section 1, line 1, "MEASURED OR ESTIMATED IN MINE DP EXPOSURE (µg/m

^{3})'' should read "MEASURED OR ESTIMATED DPM CONCENTRATION (µg/m

^{3})''.

2. On page 58201, Figure V-4, section 2, line 21, "AVERAGE TOTAL SHIFT PARTICULATE OUTPUT (gm)'' should read "AVERAGE, TOTAL SHIFT, ENGINE EMISSION RATE (gm/hp-hr)''.

[Figure V-5]:

1. On page 58205, Figure V-5, section 1, line 1, "MEASURED OR ESTIMATED IN MINE DP EXPOSURE (µg/m

^{3})'' should read "MEASURED OR ESTIMATED DPM CONCENTRATION (µg/m

^{3})''.

2. On page 58205, Figure V-5, section 2, line 18, "AVERAGE TOTAL SHIFT PARTICULATE OUTPUT (gm)'' should read "AVERAGE, TOTAL SHIFT, ENGINE EMISSION RATE (gm/hp-hr)''.

3. On page 58205, Figure V-5, section 3, line 4, Column B, "73 cfm/hp'' should read "173 cfm/hp''.

4. On page 58206, second column, line 3, "E(a)=(DPM(m)-I)x(Q(I)/ 35200)/[Sum(Hp(I)xTo(I))]'' should read "E(a)=(DPM(m)-I)xTs x Q(I) x 1.7/ [10

^{6}x Sum (Hp(I) x To(I))]''.

5. On page 58206, second column, line 12, "To(I) = Individual engine operating times, hours'' should read "Ts = Total shift length, hours''.

6. On page 58206, second column, line 14, insert the following before beginning of paragraph: "To(I) = Individual engine operating times, hr; "1.7 = The metric conversion factor that converts cfm to m

^{3}/hr, 1.7''; "10

^{6}= The conversion factor that converts gm to µg''.

7. On page 58206, third column, line 9, "DPM(a) = {[[Sum (E(I) x Hp(I) x To(I))] x 35,300/Q(I)] + I} x [Ts/8]'' should read "DPM(a) = [(E(a) x Sum Hp(I) x 10

^{6}/1.7 x Q(I)) + I] x Ts/8''.

8. On page 58206, third column, line 12, "35,300 is a metric conversion factor'' should be deleted.

9. On page 58206, third column, line 16, "E(I) = Individual engine emission rates, gm/hp-hr'' should read "E(a) = is the quantity calculated for section 2, Column B, the average engine emission rate, gm/hp-hr''.

10. On page 58206, third column, line 19, "To(I) = Operating time hours'' should be deleted.

11. On page 58206, third column, line 23, insert the following before the beginning of paragraph: "1.7 = The metric conversion factor that converts cfm to m

^{3}/hr, 1.7''; "10

^{6}= The conversion factor that converts gm to µg''.

12. On page 58207, first column, line 71, "DPM(c) = {Sum[(E(I) x Hp(I) x To(I)) x (35300/Q(I)) x (1-R(o)) x (1-R(f)) x (1-R(e))] x [Q(I)/Q(f)]} + I'' should read "DPM(c) = {(10

^{6}/Ts) x Sum[E(I) x Hp(I) x To(I) x (1-R(o)) x (1-R(f)) x (1-R(e))] / 1.7 x Q(f)} + I''.

13. On page 58207, second column, insert before line 17, "Ts = Total shift length, hours''.

14. On page 58207, second column, after line 21 and before the section heading, "VI. Impact Analysis,'' insert the following: "Note: The factor 1.7 to convert Q in cfm to m

^{3}/hr is determined as follows: 1 cu ft = ((2.54 cm/in)

^{3}x (12 in)

^{3}/cu ft)/[(100 cm)

^{3}/m

^{3}] = 0.028317 m

^{3}; 1 min = 1/60 hr; 1 cfm = 1.7 m

^{3}/hr; 1 gm = 10

^{6}µg; Thus Q(m

^{3}/hr) = 1.7 x Q (cu ft/min) and E(µg/hp-hr) = 10

^{6}x E(gm/hp-hr)''.

[[Page 36828]]

**II. Corrections to Proposed Rule on Diesel Particulate Matter Exposure of Underground Coal Miners (63 FR 17492)**

[Figure V-5]:

1. On page 17567, Figure V-5, section 1, "MEASURED OR ESTIMATED IN MINE DP EXPOSURE (µg/m

^{3})'' should read "MEASURED OR ESTIMATED DPM CONCENTRATION (µg/m

^{3})''.

2. On page 17567, Figure V-5, section 2, line 18, "AVERAGE TOTAL SHIFT PARTICULATE OUTPUT (gm)'' should read "AVERAGE, TOTAL SHIFT, ENGINE EMISSION RATE (gm/hp-hr)''.

3. On page 17569, first column, line 19, "E(a)=(DPM(m)-I) x (Q(I)/ 35200)/[Sum(Hp(I) x To (I))]'' should read "E(a)=(DPM(m)-I) x Ts x Q(I) x 1.7/ [10

^{6}x Sum (Hp(I) x To(I))]''.

4. On page 17569, first column, line 29, "To(I) = Individual engine operating times, hours'' should read "Ts = Total shift length, hours''.

5. On page 17569, first column, after line 30 and before line 31, insert the following before beginning of paragraph: "To(I) = Individual engine operating times, hr''; "1.7 = The metric conversion factor that converts cfm to m

^{3}/hr, 1.7''; "10

^{6}= The conversion factor that converts gm to µg''.

6. On page 17569, second column, line 19, "DPM(a) = {[[Sum (E(I) x Hp(I) x To(I))] x 35,300/Q(I)] + I} x [Ts/8]'' should read "DPM(a) = [(E(a) x Sum Hp(I) x 10

^{6}/1.7 x Q(I)) + I] x Ts/8''.

7. On page 17569, second column, line 22, "35,300 is a metric conversion factor'' should be deleted.

8. On page 17569, second column, line 26, "E(I) = Individual engine emission rates, gm/hp-hr'' should read "E(a) = is the quantity calculated for section 2, Column B, the average engine emission rate, gm/hp-hr''.

9. On page 17569, second column, line 30, "To(I) = Operating time hours'' should be deleted.

10. On page 17569, second column, after line 33 and before line 34, insert the following before the beginning of paragraph: "1.7 = The metric conversion factor that converts cfm to m

^{3}hr, 1.7''; "10

^{6}= The conversion factor that converts gm to µg''.

11. On page 17570, first column, line 19, "DPM(c) = {Sum[(E(I) x Hp(I) x To(I)) x (35300/Q(I)) x (1-R(o)) x (1-R(f)) x (1-R(e))] x [Q(I)/Q(f)]} + I'' should read "DPM(c)= {(10

^{6}/Ts) x Sum[E(I) x Hp(I) x To(I)x (1-R(o)) x (1-R(f)) x (1-R(e))] / 1.7 x Q(f)} + I'.

12. On page 17570, first column, insert in line 41, "Ts = Total shift length, hours''.

13. On page 17570, first column, after line 47 and before the section heading, "VI. Impact Analysis'': insert the following: "Note: The factor 1.7 to convert Q in cfm to m

^{3}/ hr is determined as follows: 1 cu ft = ((2.54 cm/in)

^{3}x (12 in)

^{3}/ cu ft)/[(100 cm)

^{3}/m

^{3}] = 0.028317 m

^{3}; 1 min = 1/60 hr; 1 cfm = 1.7 m

^{3}/hr; 1 gm = 106 µg; Thus Q(m

^{3}/hr) = 1.7 x Q (cu ft/min) and E(µg/hp-hr) = 10

^{6}x E(gm/hp-hr)''.

**II. Close of Rulemaking Records**

The post-hearing comment periods for both proposed rules will close concurrently on July 26, 1999. Commenters are encouraged to submit their comments on or before that date. This will allow the public 15 months from the date of publication to comment on the underground coal proposal, and nine months to comment on the metal and nonmetal proposal.

Dated June 30, 1999.

J. Davitt McAteer

Assistant Secretary for Mine Safety and Health.

[FR Doc. 99-17326 Filed 7-6-99; 9:45 am]

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