Pollution of Streams by Coal Mine rainage Beneficial Effects of Sealing Abandoned Coal Mines WILLARD W. HODGE West Virginia University, Morgantown, W. Va.
G
ENERAL, regional, and local problems in trade waste-disposal and the prevention of unneceseary stream pollution have arisen with the rapid development of the United States as an industrial and manufacturing nation (12, 19,60, 21, SOA, 31). Some fifteen years ago the states in the Ohio Basin had a serious regional water supply problem in the offensive tastes and odors caused by phenolic wastes discharped into the streams by gasworks and by-product coke plants (28, 48,49). Cooperative efforts by the health departments of the states and the industries concerned have practically solved this problem, with profit to some of the companies from the sale of recovered phenols (33). With federal support these states are now engaged in the much greater task of reducing the excessive pollution of their streams by the acid drainage from thousands of coal mines.
Nature and Extent of Acid Mine Drainage The proper disposals of coal mine wastes, such as “gob,” “bug-dust,” rock, sulfur mud, and liquid mine drainage have long been problems to the mine operators, not only in the United States but in Germany and some other European countries, according to Bach ( 2 ) . However, most of the coal mines in Great Britain are deep, relatively dry shaft mines with coal of low sulfur content and many of the mines in France have a thick limestone cover; hence the disposal of vast volumes of acid mine drainage is not a necessity in those countries (11, 36). I n the United States the opening of the coal mines in Pennsylvania, West Virginia, Ohio, and neighboring states resulted in many of the formerly alkaline streams becoming acid, especially during peFiods of low flow, As early as 1899 bills were introduced in Congress giving army engineers power to prevent the acid pollution\of navigable waters ( 1 1 ) . According to Trax (64, 56) the Youghiogheny River a t McKeesport, Pa., had in 1890 become a t times sufficiently acid to kill fish, and prior to 1908 had sometimes reached an acidity of 200 p. p. m. Analyses of Youghiogheny R i d e r - water in 1906-7 (Reading from T o p t o Bottom) L~~~~~ pIpEFROM M~~~ oPEN- showed that twenty-nine of the thirty-five samples were acid, some containing as high ING TO Box TRAP;Box TRAP AT ENDOF PIPELINEFROM SEALED as 66 to 75 T). T). m. (14). The Monongahela River a t Pittsburgh was reported by Drake OF SURFACE OPENING; WATER CoNsTRUCT1oN DIVERSION cHANNEL IN wEsT vIRGINIA (16B) to have occasionally become acid MIXINGREGION before 1900. Among the many others 1048
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IUDUSTRIAL AND ENGINEERING CHEMISTRY
In 1932 the acid pollution of the Ohio River was equivalent to more than 3,000,000 tons of concentrated sulfuric acid. Annual losses from excessive corrosion, “red water” difficulties, and increased costs for treating water supplies were conservatively estimated at $lO,OOO,OOO. The water supplies of 5,000,000 people were affected. Most of the sulfuric acid and iron sulfate were formed by the moist oxidation of the pyrites in open coal mines. A regional program for air sealing abandoned coal mines was begun in December, 1933, under the supervision of
who lrnve invcstigntetl the acidity of this river are Trax (54) i n 1910, Roberts (44)and other army engineers in 1911, Young (60) in 1021, Clieniical Nlianoe for the Army Engineers ( 1I ) and Collins (0)in 1!123, Hodge (#9,3O) in 1922-34, .and Carpent,er and Iferndon (7) in 1033. For many years the alkalinity of the Allegheny River neutralized the excess .acidity of the Monongahela at their confluence in Pittsburgli ,to forin the Ohio. However, the records obtained by Drake (1S.4) show that the annua.1 average alkalinity of the Alle:gheny fell from 24 p. p. m. in 1909 to 5 in 1929, and during tlie summer months of recent years portions of this river have become a.cid. Hodge and Sieliaus (SOA) reported that during the summer of 1934 the Ohio River at Vheeling, W. Va., was acid for 48 corisecut.ive days. ’4 rnaxii~iuinhardness .of 240 p. p. NI. was reached on the last day of this prolonged period. These rivers flow through oiie of the most highly industrialized regions of the world (Figure 1). The Oliio River is ,981miles in length (RI) and the Allegheny River from Pittsburgh to its headwaters is over 400 riiiles long ($0). The .Ohio River drains an area of 203,900 square miles iiilinbited .by about 16,000,(100 people. Apprijximatcly TO00 square
1049
the U. S. Public Health Service, in cooperation with the states in the Ohio Basin. Funds for the projects were secured from the CWA, FERA, and PWA. Costs have been low, and many unemployed have been given useful work. Within three years over 47,000 openings in 13,500 abandoned coal mines have been sealed: reductions in acid produced have been from 25 to over 80 per cent. Diversion of surface water from mines has greatly reduced the quantity of sulfuric acid in the drainage from some mines. Improvements in the quality of many water supplies have been reported.
miles are uuderlain with true or more seairis of coal; only alwot 600 square miles of the coal area have been mined (9595). The acid and iron sulfate wastes from the pickling operations in lrundreds of iron and steel mills, and acid sludge from inany oil refineries and other maiiiifacturing plants are amptied into the streams. Investigations reported by Yoiirig (60) showed tirat often these Iaciories also discharge alkaline trade wastes which help to neutralize tlw acid industrial wartes; alxmt 90 pr:r cent of the acid in the rivers is estimated to come from acid mine drainage.
Detrimental Effects of Acid Mine Drainage The treniendous load of sulfuric acid has been an obnoxious a n d destriuhre type of stream pollution. Many of the rivers in the Ohio Ifasiu are canalized (12). The acid mater caused excessive corrosion of tlie federal navigation locks and dams, ships and barges, bridges and culverts, pipe hies and plurnbing (44,57). The acid, iron sulfate, and iron oxide (red water) often destroyed all fkli and aquatic life, interfered with nature’s self-purification of the streams sonietimes perhaps favorably, in other cases detrimentally (49, 46). madr t,lie wat.er unfit, for drinking or
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VOL. 29, NO. 9
FIGCRE1 . DRAIKAGE AREAS AND COAL FIELDSOF THE OHIORIVERBASIN
household purposes, and caused unsightly reddish brown spots on fabrics in laundries and textile factories and scum on washbowls, sinks, and tubs. The water was destructive, scale forming, and unsuitable for use in locomotive and power plant boilers, in manufacturing industries (SOA, 54, GO), and in municipal waterworks. According to Davis ( I S ) , 9000 tons of sulfuric acid per day were carried by the rivers flowing through the Pittsburgh district. From extended federal and state stream surveys, it was estimated that acid drainage from coal mines was pouring into the Ohio River and its tributaries, the equivalent of over 3,000,000 toils of concentrated sulfuric acid per year (69).
Cost of Acid Mine Drainage
boiler repairs to be $800,000 and for plumbing and water supply for inhabitants in Pittsburgh, $3,000,000. A 1926 U. S. War Department Report to Congress (67)stated that “damages by acid water to floating equipment and navigation structures amount to between $500,000 to $600,000 a year in the Pittsburgh area.” dccording t o Drake (52) during 1934 a n all-time high of 3,000,000 pounds of soda ash were used at the Aspinwall slow sand filtration plant to neutralize the acidity in the Allegheny River water supplied to Pittsburgh. Many other examples could be given. Recent conservative estimates by the officials of the Works Progress Administration p l a c e d t h e extra costs and damages caused by acid mine drainage in the states in the Ohio River Basin a t $10,000,000 per year (59).
Chemical Reactions in Coal Mine “Sulfuric AcidfPlants ’ ’ Many experiments carried out by Leitch and co-workers of the Bureau of Mines (34-40), Campbell ( 5 ) , Carpenter and Davidson (6), and other researchers have proved that the production of sulfuric acid in coal mines results from the moist oxidation of the iron sulfides, pyrites, and marcasite, and “sulfur balls” present in the coal as mined. The equations (5, 34) often given for the principal reactions involved are: 2FeSz 702 + 2Hz0 = 2FeS04 f 2H2S04 (1) 4FeS04 2H2S04 0 2 = 2Fe2(S04)s 2H20 (2) 6Hz0 = 2Fe(OH)3 4-3 H 8 0 4 Fez(SO& (3)
+ +
+
+
+
The immense quantity of acid in the streams has greatly Burke and Downs (4) suggested that the mechanism of the increased costs of chemicals and treatments of many municireaction shown in Equation 1 is the result of two consecutive pal, industrial, and domestic water supplies, where no reactions : the surface reaction between iron sulfide and disother adequate sources are available. The additional costs solved oxygen from solution which proceeds slowly, and the for the treatment of Monongahela River water by the inoxidation of sulfur dioxide by additional oxygen and water to dustries and waterworks along the 50 miles from the West form the sulfuric acid according to the equations: Virginia line to McKeesport, Pa., have been carefully estimated by Trax (64)a t $801,000 per year. The annual extra FeSz 302 = FeS04 so2 (4) 2502 0 2 2H20 = 2HzS04 (5) costs and losses to water purification plants and industries in West Virginia were placed by Tisdale and Lyon (52) a t $1,000,000. Excessive rusting MINERAL ANALYSES OF ACIDMINEDRAINAGE AXD OF MINEDRAINAGE TABLE I. PARTIAL and corrosion of culverts in POLLCTED STREAMS ( I N PARTSPER MILLION) the higliways of West Virginia Mine 1 Mine 2 Mine 3 Mine 4 Mine 5 Creek Ohio (Pa.)a (Pa.)a (W. Va.)b (W. Va.)b (W. Va.)C (W. V a . ) c RiverC were foucd by Downs (15) to 10,413 4,718 33,600 5,262 2,050 7 8 1,147 94.6 289 5 be costing the state $500,000 Total solids 8 0 ... Si02 and insol per year. Officials of two rail1,532 ‘351 5,900 460 15.5 181.3 1.2 Fe 83 346 A1 roads (3, SOA) stated that the 477 205 3 46 3 42 9 682 256 254 Ca 19 3 32.2 11 0 12 acid mine waters increased the 20 124 161 L Mg 1,122 259.6 164 5 3,560 19,300 6,066 2,684 so4 annual expenditures of treating 9.9 20 8 23 3 39 10 ... c1 2 0 4,225 778 the water used on their lines Free H2S04 +i54 ’360 22,700 1,375 ... Acidity 5’1 ... in West Virginia by approxi... 2 0 2 9 . . . . mately $75,000. For two large $ k(soap , l hardness ... .. . 937 362 116 method) as CaCOa ... r a i l r o a d s in the Pittsburgh Analyses by Trax ( 1 1 ) . area Young (60) e s t i m a t e d b Analyses by Carpenter and Herndon (7). annual extra costs due to acid Analyses made i n author’s laboratory. stream waters for locomotive
+ +
Q
+
+
‘
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IZDUSTRIAL .4ND ENGINEERING CHEMISTRY
Under proper physico-chemical conditions, reaction 5 may proceed rapidly; under other conditions, such as the presence of calcium sulfate on the surfaces of the pyrites, the reactions are inhibited. Experiments by Nelson, Snow, and Keyes (42) showed that the rate of oxidation of pyritic sulfur in coal was increased by higher temperatures, increased fineness of the material, and the addition of ferric sulfate to the coalwater mixture. There are still unexplained factors in this problem of the production of such enormous quantities of iron sulfate and sulfuric acid in the open mines and the nature of the various compounds formed (5, 63). However, the essential factors in the formation of the acid apparently are the exposed free surface area of sulfur-bearing material in the mine, the relative concentration of oxygen in the air in the mine and of dissolved oxygen in the water films in contact with the surfaces of the sulfur materials, and the rate of removal of the iron sulfate and sulfuric acid formed. Methods for the analysis and determination of mine drainage have been investigated by Campbell (6),Selvig and Ratcliffe (45), and the U. S. Public Health Service laboratories. The chemical analyses of mine waters give remlts varying over a very wide range, but those in Table I are fairly representative. Routine chemical tests on more than fourteen thousand samples of mine drainage have been carried out in the West Virginia University laboratories under the West Virginia Mine Sealing Program; a few of the results are as follows:
1051
acid with limestone, lime, marl, or soda ash; (4) completely closing the mine; (5) chemical processes for the recovery of valuable by-products; (6) dilution of the mine drainage; (7) diverting acid drainage to streams already hopelessly polluted; (8) air-sealing abandoned coal mines and workedout entries in active mines; and (9) diversion of surface water from entry into the mines. High costs and various technical difficulties have practically eliminated the use of methods 3 to 6. To neutralize with lime the acid from mines in central and western Pennsylvania, Crichton ( I O ) estimated the costs for construction of treating plants a t $75,000,000 and for lime a t $41,062,500 to $68,437,500 per year; there would also be over 1,852,000tons of sludge to handle and dispose of. Methods 1, 2, and 7 have proved applicable in only a few cases. Methods 8 and 9 are the only ones of sufficiently low cost and of proved effectiveness for combating the destructive and dangerous pollution of streams by acid mine drainage (27, 40,5I,52, 58, 59).
Increase in Acid Mine Drainage
The development of coal mining operations and the opening of new mines caused a rapid increase in the quantities of the sulfuric acid flowing into the streams. The rate of increase in production of acid by coal mines in West Virginia was found by Herndon and Hodge (26) to be approximately 176,000 pounds per day. Often the abandoned mines made as much acid ( I O , 35, 39) as the acMine 1 Mine2 Mine 3 Mine 4 Mine 5 Mine 6 &tine 7 tive mines. Some coal mines P. p . m. acidity to: 1,260 3,100 abandoned for 15 to 40 years 22,100 3,000 30 Methyl red (cold) 1,960 5.500 120 29.600 Phenobhthalein (hot) 2.400 1,480 6,500 9.400 are still producing highly acid 4.2 3.3 1.7 3.2 2.5 3 2 PH 2. drainage (8). Investigations 22 6 66 240 233,280 110 20 1 Flow gal /min 634 2,130 3:030 233 HzSda, lb:/day’ 1,955 1,560 113 by the army engineers and the NOTE: Results of routine tests reported by E. H. Martin and P. N. Brown, W. Va. Mine Sealinn Program (WPA). state h e a l t h d e p a r t m e n t s showed that the acid water was Most of the coal mines in the Ohio Basin. produce acid extending farther down the Ohio River each year. Practically no funds were available for combating the acid pollution, aldrainage as indicated. In the famous Indian Creek Pollutions Court Case, it was reported ( I O , 35) that, of three hunthough the daily contribution of about 20,000,000 pounds of sulfuric acid to the Ohio River and its tributaries detrimendred mines investigated in Pennsylvania, only four produced tally affected the water supplies of some 5,000,000 people livalkaline drainage. A number of mines in the southern West Virginia coal fields, where the sulfur content of the coal is ing in the Ohio Basin. very low (around 1 per cent or less), are reported by Herndon Government Cooperative Program and Hodge (26) to have alkaline drainage. In some cases these alkaline mine waters are actually used for municipal In 1933 Surgeon General Hugh S. Cummings, of the U. S. Public Health Service, called a meeting of the heads of the water supplies (27). The drainage from eight mines in southwestern Indiana examined by Leitch and Yant (38) health departments of the states in which the acid pollution showed free acid ranging from 270 to 33,000 p. p. m. and was most serious (69). The result was that these officials total acidities from 1,800 to 92,000 p. p. m. Many anthracite sponsored projects, in cooperation with the Federal Works mines also produce acid drainage (11). Program, for sealing acid-producing abandoned coal mines in their respective states. Sealing consists in closing the mine Methods for Reducing Mine Acid Pollution of openings so that the drainage in the mine can flow out through Streams a water-sealed trap and so that practically all fresh air and surface water is kept out of the mine. The states most conFor more than twenty years laboratory researches and cerned were Pennsylvania, Ohio, West Virginia, and Xenfield investigations have been in progress to ascertain the tucky. After the projects were approved, the state health best method for reducing the destructive pollution of streams departments, largely through their sanitary engineering diby acid mine drainage. Since 1925 a group of chemical and visions, organized the mine-sealing work in each state under mining engineers and chemists a t the Bureau of Mines under the general supervision of the U. S. Public Health Service. the leadership of Sayers, Yant, and Leitch (34-40) have done The first allotment of funds for sealing abandoned coal mines intensive work on this problem, as have also Stevenson was $3,500,000 obtained in December, 1933, from the Civil (46, 47) and colleagues of the Pennsylvania Department of Works Administration. Later allocations of funds have been Health, and the sanitary engineers and chemists in the health made by the Federal Emergency Relief Administration and departments of the other states who were signatories to the the Works Progress Administration. Alabama, Indiana, Ohio Basin Interstate Stream Conservation Agreement of Maryland, and Tennessee have also received WPA funds for 1924 (49, 68). Some of the others who have worked on this use in reducing stream pollution caused by drainage from problem are Eavenson (17, 18), Tracy (53), Handy (23), abandoned coal mines and industrial plants. Carpenter and Herndon (7), Campbell ( 5 ) , and a number of commercial firms (87). Extent of Mine-Sealing Program The more important methods developed for reducing the mine acid pollution of streams are: (1) impounding the mine When the mine-sealing program started late in 1933, comdrainage; (2) flooding abandoned mines; (3) neutralizing the paratively few data had been assembled as to the total num-
‘
ber of abandoned mines and the number of openings which would have to be sealed in each of the states. Perhaps the most detailed study of individual coal mines and the acidity of their drainage available a t that time was that by Herndon and Hodge (26). Based on coal mine acreage exhausted, an average of 1000 gallons of mine water drainage per acre per day (18), and the data from thousands of acidity p H determinations on drainage from different mines, they estimated that the coal mine “sulfuric acid plants” were pouring daily into the streams of West Virginia a total of 168,349,000gallons of mine drainage, containing the equivalent of 2,876,000 pounds of concentrated sulfuric acid. From the results of early and rather hurried mine and stream surveys, Tisdale and Lyon (62) estimated (April, 1935) the daily total of acid produced by 1440 coal mines in West Virginia at 3,528,000 pounds. Results of more detailed investigations reported by E. W. Lyon place the total acid production from coal mines in this state a t 2,282,000 pounds per day. This checks closely with the total estimated by Herndon and Hodge in 1933. The distribution by states of the coal mine acid drainage as stated in January, 1937, by the WPA Information Service (59) is as follows (in pounds per day): State Alabama Indiana Kentucky Maryland Ohio Pennsylvania W. Virginia Total
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INDUSTRIAL AND ENGINEERING CHEMISTRY
1052
--Nature Active 13,000 700,000 807,000 384,000 913,300 4,284,200 664,400
of Mining OperationMarginal Abandoned
Total Acid
40,000 900,000 1,688,000 244,000 1 790 900 4:373:700 1,378,400
53,000 1,800,000 2,669 000 667:ZOO 2 704 200 9’117’600
200‘000 174:OOO 39,200 459;700
239,500 -7,765,900
1,112,400
~
10,415,000
2:282:300 ___ 19,293,300
The acid produced by abandoned coal mines amounted to 10,415,000 pounds per day, approximately 54 per cent of all the mine acid flowing into the rivers. Sealing these abandoned mines does not interfere with but has actually benefited the coal mining industry.
Organization and Procedure The Federal Program for Sealing Abandoned Coal Mines as now organized is under the general supervision of the U. S. Public Health Service. The health department of each state has direct charge of the mine sealing within its own borders. The state sanitary engineer may be the director of the state program, and he has a competent mining engineer as the assistant or administrative director with a staff of field and laboratory engineers and chemists to carry on the technical work involved. Most of the labor in sealing the mines has been done by experienced miners, many of whom would have been on relief rolls otherwise. In recent years funds for the work have been secured from the WPA and are allocated to the respective state projects by the U. S. Public Health Service. The mines are sealed in accordance with the basic specifications furnished by the Pittsburgh station of the U. S. Bureau of Mines. The general procedures for sealing abandoned coal mines have been published by the U. S. Public Health Service (66A). The reasons for the methods adopted and sequence of operations have been discussed by Chapman (8) and Whitman (68.) First there is the reconnaissance survey to locate all the bituminous coal mines by counties and by watersheds, classify mines into marginal, active, or abandoned, map the mines and the stream into which each discharges drainage, and secure a general view and plan of the work projects in the given area. The second group of operations includes the detailed mine inspection and survey for wet and dry openings, cave holes, crop falls, or crevices through which air and surface water might enter the mine; the opening8 vary from a few to
around five hundred in some mines from which the pillars have been drawn. Index and detailed sketches of the mine and its openings and the location of streams, railroads, and highways are made, and these data are transferred to the U. S. Geological Survey topographical sheets or county maps. Samples of the mine waters are collected, including some taken from stations above the mine or mines polluting a stream, and from below the lowest drainage point of the mines. These samples are tested for pH and for reaction to methyl red in cold solution and to phenolphthalein in hot solution. The quantity of drainage from the mines is determined by weir and float methods or, if the rate of flow is small, by the use of buckets of definite capacity. Permission to seal the mine must also be obtained from the property owners. All reports are checked a t Division Headquarters, and finally the Assistant Director approves or disapproves sealing the mine, except when the estimated mine sealing cost exceeds $10.00 per ton year; then special approval of the U. S. Public Health Service Regional Bureau must be obtained before the work is started. Factors considered in deciding whether or not to seal a mine are acidity of the drainage, quantity of the effluent, relation to the stream flow, condition and uses of the stream, unit cost of acid reduction, feasibility of the project as to efficient sealing and diversion of surface waters flowing into the mine, and value of the work to local communities and to the general water supply conservation. The third group of activities is concerned with construction work in sealing the mine and of diversion channels for surface waters flowing into the mine. If the mine is sealed, then the fourth group of procedures follows; it involves check sampling and chemical tests and analyses, inspections by the district engineer, follow-up work to make sure that all air leaks are sealed, maintenance work, and reports and records of the job and the results obtained.
Methods of Sealing Mine Openings The best method of sealing the openings is determined by the district engineers who are usually experienced mining men, and every precaution is used for the safety of the workmen. The more common types of drainage-opening seals, as described by Hatch ($4, 26) are: masonry wall with sewer trap, somewhat like a part of the S-trap below a kitchen sink; masonry curtain wall with dam and overflow trough; and masonry wall with earth fill and box sump trap with overflow opening. The more common types of seals for dry openings (24,61) are masonry walls, masonry walls with earth a s , and heavy earth fills. Other types of seals are used where special conditions require them., The work has been carried out a t a relatively low cost. Stone and timber near the mines have been utilized as construction materials. Some of the mining companies have donated steel, lumber, cement, and mine props. I n general, the cooperation of the interested parties has been good.
Expenditures and Mine Sealing by States The average costs in the West Virginia program u p to November, 1936, given by Tisdale and Chapman (51) are as follows: Construction Maintenance Total
Per Opening $ 89 00
Per Mine
16.00
$798.00 144.00
$105.00
$942 00
During the 3-year period the total expenditures for airsealing some five hundred abandoned coal mines in West Virginia had been approximately $500,000. More than thirty-six hundred openings had been closed. The reduction in acid produced is calculated as 44,000 tons per year-a cost of about 87 cents per ton of acid eliminated if the investment
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INDUSTRIAL 4 U D EYGI\EEHIUG CHEMISTRY
is figured on a Isyear basis. This is a reasonable cost for so large a reduction in the destructive stream pollution (52). The average cost will probably rise as the work continues, since most of the low-cost sealing on highly acid-producing mines has already been done. The expenditures in Pennsylvania for mine-sealing work to Jnouary, 1937, had been approxiinatcly $1,500,000. The work was heing carried forward in tnenty-two counties, seventeen hundred men were regularly employed, and soine thirty tl~ousaiidopenings had been dosed; the air-sealing work on 208 mines WBS completed, andwork Ti-as being continued on 139 other partly sealed mines (5.9). There are about forty-five hiindred abandoned coal mines in twenty-four counties in Ohio, From the mine and stream surveys made, Hatch (24) estimates that the niiiies in the Ohio vatershed in his state were daily contributing over 3,000,000 pounds of sulfuric acid to the Ohio River. By Octohzr 1, 1936, 570 mines had been air-sealed by closing some thirteen thousand opmings. Many earth fills were used with allowance for the mine drainage to flow out through a waterieitled trap in a masonry wall (59). In Kentucky there were approximately forty-three hundred abandoned coal mines, of which one hundred and ten had been sealed before January, 1937. This required closing 633 openings, and A. T . McCormack, State I-iealth Cominissioner,
ABANDONEDCOALMINE OPENINGIN W E ~ TVIEGINIA, A
BOX-SEALED WITH MASONRY WALL
COALMINE OPENINGIN Omo, TRAP-SEALED WITH MMONXY
1053
reported the work of sealing was in progress on seventy other iniiies (5,9). The writer does not have available published reports on tlie mine-sealing programs which have more recent,ly been started in h,larylaud, Inrlinna, Tennessee. aiid Alabama. However, Hall, State Director, states that the largest single source of acid pollution in Maryland is through the Hoffman Drainage Tunnel 75-hirh discharges at inaxiiiiuin flow about 19,000 tons of acid per year (2,"). Since air sealing is not practic a l k in this case, tlit: mine openings will be earth-Bled, and tlie five streams \vtiicti flow over this area will be diverted from entering the mines; hence the river water will not become acid and so can be used for dilution purposes.
Reduction of Acid Pollution of Streams The Program for Sealing Abandoned Coal Mines has now heen under vay for only 31j3 years. A general survey of its
accomplishments reveals that many beneficial results have already heen attained (69). Since the time faetor is often important in the reduction of the quantity of acid produced in the coal mines, the favorable effects of mine sealing are more noticeable in the states in which the program was first started on an extensive scale. The greatest amount ol work and expenditures of monry for minr sealing have been in Pennsylvania, and the results prove t,he success of tlie methods used. A tvoical examnle is the Commerce go. 4. niinc
INDUSTRIAL AND ENGINEERING CHEMISTRY
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major diversion projects, including iilling the cave holes, were undertaken. The results of the tests made in January, 1937, under original conditions and in April, 1937, when the projects were about 95 per cent completed showed a diversion of 5,446,700 gallons of water and elimination of 135,559 pounds of acid per day. Theee are daily reductions of 52 per cent in volume of drainage and 56.5 per cent in acid produced. Estimated costs for the job are about 20 cents per ton year. The large volume of unpolluted water is diverted to the creek and aids in the dilution of the now much smaller quantity of acid mine drainage. This greatly improves the condition of the stream which flows into the basin above the immense, new government dam on the Tygart River, A record of the tests and calculated results made on this mine are given in Table I1 (8). Some fifteen bills were introduced in Congress last year for further federal support (32, 62) in reducing unnecessary stream pollution as a result of the many advantages already observed from air sealing abandoned coal mines and diversion of surface waters from both T I M E IN MONTHS active and abandoned mines. The BarkleyFIGURE 2. DECREASE IN STREAM ACIDITYDUE TO AIR SEALING ABAXDONED Vinson and the Lonergan BiIls before the MINESON THE WATERSHED present Congress indicate that we may be entering upon a period of greatly extended efforts for the conservation of our national water resources trations will be outlined here. Previous to 1936, during the dry summer months the Monongahela River a t Morgantown (41). Naturally there are differences of opinion ( I ) as to how far federal assistance and control shall go and the measwaterworks had attained a n acidity of 49 p. p. m.; during the ure of responsibiIity to be assumed by the respective states drought of 1936 the highest acidity observed was 6 p. p. m. in the disposal of industrial and sewage wastes in streams. Two large mines draining acid into Beaver Creek, a tributary However, the Program for Sealing Abandoned Coal Mines of the Cheat River, were sealed in 1934. For years no fish is a n outstanding illustration of the helpful cooperati9n of had been seen below this point of pollution. Trout were the Federal Government with state authorities in the recaught last spring within 6 miles of the former point of severe duction of dangerous and destructive stream pollution withacid pollution (60, 61). out handicapping the mining industry, and of improving for The data plotted on Figure 2 were furnished by Bardwell many industries and millions of people the quality of their ( 3 ) . The data were obtained from the records of a railroad’s available water supplies. water-treating plant at Whitman Junction on Island Creek in southern West Virginia. The curves show that from JanuFOR SURFACE W A T E R DIVERSION PROJECTS ary, 1931, to March, 1935, the TABLE 11. MINE DRaINAGE TESTS IN PRESTOX COUNTY, W, VA. creek water was always acid. Temporary Total Date Mine -4cidity Acidity Most of the abandoned coal of Opening Totai Mine t o Phenolt o Methyl mines on this watershed were Sample 40. Sampling No. Has04 Drainage phthalein (Hot) p H sealed in 1933 and 1934. I n Lb./day 1000 gal./day P . P. m 15 30,800 1,944 0 1 900 3 1 1935the average monthly acidi9,586 1/12/3 3,024 0 2:400 3 1 16 60.500 9,587 ties were greatly reduced and 3 1 142,500 5,184 0 3,300 17 9,588 1s 34 200 3 4 . 120 20 2 9,589 for 2 months were actually 19 281 56 2 600 3.2 460 9.590 Still alkaline in r e a c t i o n Totala 234,115 10,228 4 further improvement in the 15 141 12 9 1,300 3.3 1,000 12,152 4/5/37 alkalinity of the stream water 1,400 3.4 1,200 16 5,045 432 0 12,153 1,780 2,220 3 3 21,500 1,137 6 17 12,154 is apparent from the 1936 and 1s 18 3 6 600 3.4 500 12,155 20 3,300 247.7 1,600 3 4 1,260 12,157 1937 data. 1,560 74 9 2,500 3 3 2,000 21 12,158 An outstanding accomplish12,159 22 128 9 4 1,640 3.4 1,300 12,156 ment of the present year in reducing the quantity of sulfuric Totala 31,818 1,938.3 acid produced in a partially abandoned mine by diversion of surface water is reported by original 239,103 10,560.4 2,240 Chapman (8). Since mining Natural flow, estd. operations were being carried Check sample on in part of the mine, air sealing could not be considered. Large q u a n t i t i e s of surface water were flowing through cave holes into the mine, Four
.
SEPTEMBER, 1937
INDUSTRIAL AND EN GINEERING CHEMISTRY
The great reduction in quantity of acid produced in coal mines by reducing the concentration of oxygen in the mine stir through air sealing the openings and by diverting surface waters from the mines proves the correctness of the early conclusions made from laboratory and field experiments as to the importance of these components in the chemical reactions (Equations 1, 2, and 3) forming the sulfuric acid in mine drainage. More thorough and frequent removal with controlled combustion of the fines, “gob,” sulfur balls, and sulfur mud from marginal and active mines would greatly reduce the quantity of the third component in the reaction and doubtless lead to further reductions in the quantities of acid mine drainage polluting the streams of the Ohio Basin.
Acknowledgment The author acknowledges with grateful appreciation the cordial cooperation received in the furnishing of recent data, photographs, and information by E. S. Tisdale, C. L. Chapman, E. H. Martin, L. K. Herndon, B. F. Hatch, G. L. Hall, R. C. Bardwell, Roscoe TVright, 9.W. Yon Struve, and E. W. Lyon. Photographs were furnished through the courtesy of Mine Sealing Programs, U. S. Public Health Service and Works Progress ddministration.
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(24) Hatch, B. F., private communication, 1937. (25) Hatch, B. F., Water W o r k s & Sewerage, 81, 99-100 (1934). (26) Herndon, L. K., and Hodge, W. W., W. \‘a. Univ. Eng. Expt. Sta., Research Bull. 14 (1936). (27) Hodge, W‘. W., paper presented before Central States Section, Am. W&terWorks Assoc., Aug., 1936. (28) Hodge, W. W., W. Va. Univ. Eng. Expt. Sta., Tech. Bull. 1, 40-54 (1927), (29) Hodge, W. W., W. Va. Univ. Sci. Assoc., Bull. 1, No. 4, 35-43 (1924). (30) Hodge, W.W., and Newton, R . , W.Va. Univ. Eng. Expt. Sta., Tech. Bull. 7, 52-69 (1934). (30A) Hodge, W. W., and Niehaus, E . J., T.V. Va. Univ. Eng. Expt. Sta., Research Bull. 15 (1936). (31) Hoskins, J. H., and Crohurst, H . R., IND.ENG. CHEM.,22, 1340-2 (1930). (32) Jansson, M. E., S.Am. Water Works Assoc., 27, 359-72 (1935). (33) Jones, H. E., W. Va. Univ. Ena. Expt. Sta., Tech. Bull. 1. 31-9 (1927); Chem. & Met. Eng, 35,215-18 (1928). (34) Leitch, R. D., paper presented before Am. I n s t . ,Mining Met. Engrs., Feb., 1937. (35) Leitch, R. D., U. S.Bur. Mines, Repts. Investigations 2725 (1926) ; Coal M i n e Management, 5, 38, 58-63 (1926). (36) Leitch, R. D., U. S. Bur. Mines, Repts. Investigations 2889 (1928). (37) Ibid., 3098 (1931). (38) Leitch, R. D., and Yant, W. P., Coal Age, 35, 78-80 (1930). (39) Leitch, R. D., and Yant, W. P., U. S. Bur. Mines, Repts. Innvestigations 2895 (1928). (40) Leitch, R. D., Yant, W. P., and Sayers, R. R., Ibid., 2994 (1930). (41) Natl. Resources Comm., Special Advisory Comni. on Water Pollution, Rept. on Water Pollution, 1935. (42) Nelson, H. W., Snow, R. D., and Keyes, D. B., ISD.EKG.. CHEM.,25, 1355-8 (1933). (43) Purdy, W. C., U. S. Pub. Health Service, Bulls. 131 (1923) and 198 (1930). (44) Roberts, T. P., Proc. Engrs. SOC.Western Pa., 27,375451 (1911). (45) Selvig, W. A., and Ratcliffe, W. C., J. IXD.ENG. CHEM., 14, 423-6 (1922). (46) Stevenson, W. L., M i n i n g Congr. J . , 12, 423-6 (1926); S. Pa. Water Works Operators’ Assoc., “Germicidal Effects of Acid Mine Drainage,” 1922. (47) Stevenson, W. L., Proc. 3rd Intern. Conf. Bituminous Coal, 2, 912-23 (1931). (48) Theriault, E. J., IND. ENG.CHEM.,21, 343-6 (1929). (49) Tisdale, E . S., J . Am. Water W o r k s Assoc., 23, 1357-65 (1931). (50) Tisdale, E. S., paper presented before Am. Inst. Mining Met. Engrs., Feb., 1937. (51) Tisdale, E. S., Chapman, C . L., and others, Bull. W. Va. State Health Deot. and State Water Commission. 1937. (52) Tisdale, E. S., and Lyon, E. W., J. Am. Water W o r k s Assoc., 27,1186-98 (1935). (53) Tracy, L. D., Trans. Am. Inst. M i n i n g Met. Engrs., 66, 609-25 (1921). (54) Trax, E. C., Eng. News, 64, 362-3 (1910); Eng. Record, 62, 371-2 (1910). (55) Trax, E. C., W. Va. Univ. Eng. Expt. Sta., Tech. Bull. 6, 5-19 (1933); Water W o r k s Eng., 87, 774-5 (1934). (56) U. S.Army Engrs., “The Ohio River,” 5th ed., 1935. (56A) U. S. Pub. Health Service, Manual of Policy, Organization, and Uniform Practice, p. 4 , 1936. (57) U. S. War Dept., M i n i n g Congr. S., 12, 523-4 (1926). (58) Whitman, R. V., paper presented before Am. Inst. Mining Met. Engrs., Feb., 1937. (59) Works Progress Admin., Information Service Release, Jan., 1937. (60) Young, C. M., S.Am. Water Works Assoc., 8, 201-17 (1921).
RECEIVED April 20, 1937. Presented before the Division of Water, Sewage, and Sanitation Chemistry at the 93rd Meeting of the -4merican Chemica! Society, Chapel Hill, N. C., April 12 t o 15, 1937.
