Mining practices

Contents

PAGE

THE MINING DISTRICTS OK JOPLIN AND SOUTHEAST Missonti ........ 1-26

Four articles by II. IV. Kitson

II -Mississippian >{<- Ordovician -yCambria/U- .-^Cambrian &*<•

EAST! |

FIG. 4. GEOLOGICAL SECTION THROUGH JOPLIN AND SOUTHEAST MISSOURI — AFTER BUCKLEY and make his payments on long and easy terms at a rate fixed in 1862 of $1.25 per acre.

In the Joplin district the first-reported discovery was made by William Foster at Granby in 1850. This, like other succeeding discoveries, was made by accident in the course of well digging for water. Galena was the ore mined from the shallow deposits where shafts were

Boston. In 1856 Blow & Kennet started operations on a larger scale. Lands were leased and furnaces erected, and railroad construction started. The Civil War put a stop to development in 1861, but the mines were operated alternately by both sides during that period. Eight after the war the Granby Mining and Smelting Co. was organized, the various interests combined and operations

MI.\L\C PRACTICES resumed. Galena and cerrusite were the first ores mined. Calamine and sphalerite were later recognized, and upon completion of the railroad to Granby, zinc ores were shipped.

For the first 30 years galena and calamine were the main ores of the district, but later sphalerite ores took the lead, with calamine second and galena third. The first modern concentrator was built in 1898, the ores up until that time having been concentrated in hand jigs.

The history of the district is one of spasmodic rushes and booms, followed by hasty production on a profitable if wasteful scale. The land, primarily agricultural, was largely settled by a farming people who knew little of mining. For a number of years Granby was the center

Impervious

Fio. 5. DIAGRAM SHOWING OZARK ARTESIAN CIRCULATION — AFTER SIEBENTIIAI.

of prospecting. Later, strikes were made by accident at Joplin and at Oronogo, at which points mining activity became intense. Discoveries followed at Webb City, again by accident, and another rush was made to this section, and such has been the development of the region from the beginning. Strike after strike was made, with intense exploitation in each section, until there became a scattered group of camps with Joplin as a center. Between most of the camps there are wide stretches undeveloped that may prove to be valuable mining ground. There are well-known instances where mining activities have linked together neighboring mining camps by the lateral extension of the orebodies, as from Oronogo on through to Duenweg, a stretch of seven miles, and more recent operations point to a probable repetition of such expansion in other parts of the district. The ground between Duenweg and Granby, under the stimulus of efficient prospecting, may prove to be a continuous run of ore. The undeveloped stretch between Carthage and Neck City forms another possibility for the future.

Early exploitation was by the grubstake plan, prospecting for the shallow lead deposits at first and later the shallow zinc deposits. The mineral had to be free and amenable to hand picking, followed by hand jigging, to be profitable. Problems of concentration came with the exhaustion of the shallow deposits and the discovery of the deeper and lower grade orebodies. Out of all this the present . milling practice was evolved, and its low cost of operation has made profitable the mining of ores producing as low as 2% of zinc concentrates. At present, however, many of the lower grade mines have been forced to close owing to the marked increase inwages and cost of supplies and the absence of a corresponding advance in the price of ores. This condition has stimulated prospecting in the newer fields of Oklahoma and Kansas, where ores of higher grade can be made to yield a better profit on the present market.

The earliest mining in the Southeast Missouri district proper was at Mine a Joe in 1801. These were shallow lead deposits in the tract later known as the Bogy Lead and Mining Co. and in 1S87 purchased by the Desloge interests. Operations at the Pratt mine, in the vicinity of Bonne Terre, started as early as is-'d. but the disseminated ores were not discovered until 1864. Four years later the St. Joseph Lead Co. was organized and diamond drilling started in the Bonne Terre section. The company purchased the land from Anthony La Grave, a property previously owned by the Yalle and Aubuchon families. The Doe Eun company started in 1887, but has recently been merged with the St. Joseph Lead Co. The Federal Lead Co. began operations in the Flat Uiver district in 1902, later acquiring the properties of the Irondale, Derby, Central and Field companies. The St. Louis Smelting and Ivelining Co. commenced in 1898 by purchasing the holdings of the Flat liiver Lead Company.

The region is well served by railroads connecting the productive districts with the smelting and marketing centers. West of the Mississippi the Kansas Southern Ey. runs from Kansas City to Port Arthur, Tex. It is the short line from Kansas City to the southeastern Kansas coal field and the Joplin zinc-lead district, and traverses the coal-producing section of eastern Oklahoma and western Arkansas. The Missouri Pacific E.H. connects St. Louis and Kansas City, serving the coal fields of northwestern Missouri, passing through Barton County, Mo., Crawford and Cherokee counties, Kan., the Joplin- Webb City zinc-lead territory, and the oil and smelting districts of Kansas and Oklahoma. It also reaches through subsidiary lines the coal mines of Arkansas and the southeast Missouri lead district. The St. Louis- San Francisco Ey., known as the Frisco Lines, runs from St. Louis and Kansas City to the heart of the Pittsburgh, Kan., coal fields and the Joplin-Miami lead district, passing to the Tulsa and Glenn Poole, Okla,, oil and gas country, and with four district lines to Texas handles a large mineral tonnage. The Frisco Lines also serve most of the smelteries.

In 1916 there was produced from the smelteries in the lower Mississippi Valley 512,000 tons of spelter, or 75% of the total production of the United States. Of this amount Kansas and Missouri smelteries produced 34%, Illinois 28%, Oklahoma 31% and Arkansas 7%. Natural gas in Kansas and Oklahoma has inade this section desirable for the location of smelting plants of which there are 17 and 14 respectively. In Illinois there are 11 plants, in Missouri three, in Arkansas three and in Indiana one.

The lead smelteries of the region are situated close to the lead-producing districts and in 191(1 yielded 236,- 000 tons of lead. The principal smelteries for the southeast Missouri district are those of the St. Louis Smelting and Refining Co., at Collinsville, 111.; the Federal Lead Co., at Federal, 111. ; the St. Joseph Lead Co., at Herculaneaum, Mo., and the Desloge Consolidated Lead Co., at Desloge, Mo. The Eagle-Picher Lead Co., one of the largest pigment manufacturers in America, has plants at Joplin and Webb City. Missouri.

The Mining Districts of Joplin and Southeast Missouri Part II

BY II. W. KITSON

Ki<;. (i. TYPK-AI. VIEW IN THK SIIEET-<;HOUM> AIJEA, SHOWING EFFKLT OF A CAVE

The Joplin district covers a territory of 3000 square miles that includes parts of Missouri, Oklahoma and Kansas, and consists of numerous scattered camps and groups of camps situated along more or less well-defined belts, shown by dark areas on the map in Fig 7. The main productive section in Missouri lies in Jasper and Newton counties; but the district extends also into Lawrence, Bade, Christian and Greene counties, all of which are in the southwestern part of the state, whence the name Southwest Missouri zinc district by which it is also known. Eastward from the city of Joplin the Missouri section extends to Springfield, a distance of GO miles, and westward to the Kansas state line. North of Joplin the active camps take in Webb City, Carterville, Oronogo, Waco, Neck City and Alba, and to the south Granby, Spurgeon, Spring City and Saginaw, making a width of 30 miles on a line northward from Granby through Dnenweg to Neck City.

In Oklahoma, the Joplin district lies entirely within Ottawa County, in the northeast corner of the state, extending from the vicinity of Miami, 40 miles west of Joplin, to the Kansas state line on the north, taking in Commerce, Quapaw, Sunnyside, Douthat, St. Louis, Century, Tar River, Cardin and Picher. The Kansas section lies in the southeastern part of Cherokee County, and, together with the Oklahoma section, is sometimes called the Miami district. The important communities in the Kansas section are Galena, Treece and Baxter Springs. The main line of the St. Louis and San Francisco R.R. passes through Miami, Baxter Springs, Galena, Joplin, Cartilage and Springfield ; and the Missouri Pacific, Kansas City Southern, Missouri, Oklahoma & Galena, and Missouri, Kansas and Texas railways connect most of the other camps with Joplin and smelting centers. This <-ity is therefore an important distributing point and an industrial as well as geographical center for the entire district; with the Southwest Missouri Ry. inter-urban electric lines connecting Galena, Webb City, Carterville, Oronogo, Neck City, Carthage and Duenweg, and a population of nearly 50,000, mine workers are able to commute to the various mines and live comfortably in the larger communities.

The panoramic view from the top of any of the innumerable " chat " or tailings piles around Joplin presents the appearance on all sides of a wide level plain, and mining communities can be observed for many miles. The various camps are marked by their mounds of " chat " piles, derricks and dummy elevators, and between them are to be seen cultivated fields and patches of woods.

The country is somewhat broken by the drainage system of the Spring River from its source west of Springfield along its westward course north of Joplin and between Joplin and Baxter Springs, where the surface has a gently rolling relief. The Spring and Neosho rivers join a short distance southeast of Miami, this district lying mostly between the angular convergence of the two, and having a topography similar to that of Joplin, level and unbroken except for one or two low hills, as at Blue Mound, in Kansas, near the state line north of Picher. The region is on the western border of the Oxark Uplift, and elevations range from 1000 ft. at Miami and Joplin to 1250 ft. and more in the eastern district.

The surface conditions of the district offer great facilities for railway construction and highways, although the rapidly growing amount of traffic over the latter has outpaced the rate of upkeep, and the roads are consequently in poor condition. The proposed concrete county road from Joplin to the new Miami fields is therefore a much-needed project. Railroad spurs have recently been extended to Richer, St. Louis and other camps in the Oklahoma district ; and in the near future the important producing centers of this district will all be connected to the main lines of one or more of the important railroad systems. On the other hand the extreme flatness of the country offers no opportunity for favorable millsites and consequently mills are all equipped with elevators inside, and " dummy elevators " with launders outside. By means of the latter the " chats " are heaped in conical piles by stages, and at the larger plants accumulate to considerable heights.

Each of the many small mills that dot the landscape is situated over a hoisting shaft, and surface or underground haulage from adjacent properties to a central number of different lessors 'from the sale of concentrates or ores from an equal number of different 5 to 40-aere tracts.

In the Missouri and Kansas sections the average unit of operations is 20 acres and in Oklahoma 40 acres. The reason for this is that most of the mines are worked under a leasing system. Mining rights are leased on land owned in small tracts by the descendants of the original settlers of Missouri and Kansas, who were altogether an agricultural people, and by the Indians in Oklahoma who own their land in tracts granted by the Government. Many of the larger companies have purchased considerable tracts of land outright and some have purchase'] the right to mine without royalty, but do not po>- the surface rights. The large number of sin;. 11 inde-

Fio. 7. MAP SHOWI.NG MINED AREAS IN THE JOPLJN DISTRICT, MISSOURI, OKLAHOMA AND KANSAS mill is rare. The prevailing hoisting practice of the district is by means of buckets, which system enables a light winding engine to be installed at the top of the headframe or " derrick," as it is more properly called. With flat surface conditions this light type of structure has the advantage of giving considerable hoisting height at a low initial cost, which condition is desirable for proper dumping headroom over mill bins or " hoppers " that are most conveniently and customarily built as an integral part of both derrick and mill. Some of the larger and more recent properties, however, are using skips and centralizing hoisting and milling operations. Such practice, however, is only practicable where the operators are not obliged to pay separate royalties to a pendent operators obtain leases usually fou 10 years and pay royalties on shipments of ore at ra. ies ranging from 2i/o to 25%, the average being about ty»% in the Oronogo-Duenweg sheet-ground mines, which are the lowest of all in grade. Since the boom in the newer fields north of Miami premiums arc asked in addition when the leases are taken, and royalties average from 10 to 15%. • Some of these premiums have run as high as $260,000 on the larger tracts. When a lease is solicited, a one-year's option for drilling and proving up the ground is given, subject to acceptance by the lessor at the end of that time, together with the previously drawn up terms of lease.

Individual orebodies are of varying size, but the range

THE MINING DISTRICTS OF JOPLIN AND SOUTHEAST MISSOURI of life is from six months to six years. Under such conditions it is apparent that little capital can be put into plant and development, and the result has been methods both in mining and milling that will yield a marketable product at the lowest possible combined cost of plant and operation, with little regard for loss in pillars underground or in the tailings 011 top. The wisdom of such policy from a commercial standpoint is evident. More elaborate methods have been attempted, but they proved commercial failures. Exact data on mine anc mill extractions in the district are, in the nature of the methods used, almost impossible to obtain. It is estimated, however, that from 10 to 15% of the orebodies remains in pillars and that from 58 to 70% is recovered in the mills.

individual ores. Concentrates of higher or lower grade than 60% are respectively allowed or penalized $1 for each unit above or below this base. An iron content of 1% is accepted, but above this amount a penalty of $1 per unit is imposed. The maximum allowable lead content in zinc concentrates is fixed at 0.3%, and amounts over this are penalized indirectly in calculating base-price quotations. Zinc silicate ores are sold on a base price for 40% zinc metal, with premiums and penalties corresponding to those established for sulphides. Concentrates of lead sulphide are bought in a similar manner, quotations being fixed on a base of 80% lead metal, with the same rate of premium or penalty per unit above or below 80% as for zinc. There are, however, no penalties or premiums for zinc or iron.

MISSOURI Joplin Blende Bumble Bee M. Co 242.140 St. Regis M. Co 264,830 Little Martha M. Co 149,150 Fifteenth Street M Co 171 300

Gibson M Co 120 800

Consolidated-Inter-State M. Co 83,410 Swartz M. Co 92,290 Malcona M. Co 65.450 Ethel Gray If . Co 62.270 New Geronimo M. Co... 63.100 Kaglewood M Co 55.370 Wise Guy M. Co 40,270 Paragon M. Co 62 700

Malsbury M. Co 25.480 Rabbits Foot M. Co 7690

Sundries . 241 610

241 210

241 210

Calamine Falkner M. Co 63,800

Webb City — Carterville

Blende Bertha A. M. Co 510,730 American Z. L. & S 458.660 Kirkwood M. Co 161,150 Queen Esther M. Co.... 170.280 Concord M. Co 156.140 Unity M. Co 86.190 Ben Franklin M. Co 72,280 Mahatmah M. Co 65,820 Nearby M. Co 47.510

Lucy Bell M Co 35 690

Shawgo M Co 13 230

220 710

Totals 2 087 O'O

220 710

Duenweg

TABLE I. PRODUCING COMPANIES OF THE JOPLIN DISTRICT

Oronogo

Blende Galena

Oronogo Circle 192,000

Aurora

Blende

Red Wasp M. Co 178,000

Bonanza M. Co 159.800

Mills & Co 62.180

Murray & Co 12,660

412,640

Calamine

Mathe-"-s-Phelps M. Co.. 70,000

Sandridare M. Co 44.240

Consolidated M. Co 34,000

KANSAS Galena

Diplomat M. Co South Side M. Co lY.eio lo'e.oid

Andrew Bros. M. Co. . . .

Wayland M. Co

C. W. Squires M. Co. . . .

Boor M. Co

3,040 116,660

Waco-Lawt

Eastern L. & Z. Co

Smart & Crane M. Co...

Total .

614.700

Granby

Blende

American Z. L. & S 66.800

Calamine

Perkins M. Co 1,400.000

,T. R. Underwood M. Co. 80.000

Woodcock M. Co 80,000

Buick M. Co 70.000

OKLAHOMA

Belville

Blende Galena

Tennessee M. Co 130.800

Culbert L. & Z. Co 45,940

Kirkpatrick M. Co 19.330

Co.

Blende Galena

803,790

545.050

206.180 Joplin Concentrating

65,660 Sponable M. Co. ...

Athletic M. Co.

Coahuila M. Co.

St. Regis M. Co.

What Cheer M.

Total produi on for the week ended Oct. 20, 1917, was: Blende, 16,283,170 Ib.

196,070

Blende

Picher Mines

2 630 400

Underwriters Land Co.

936,850

Mahutska M. Co

, 820,470

Montreal M. Co

659,740

U. S. Smelting Co

600,000

Bilharz M. Co

398,240

Admiralty Zinc Co.

. 322,290

Skelton No. 2

•300,040

Anna Beaver M. Co.

. 281,600

Bethel M. Co

. 278,840

Ramage M. Co

191,130

Metals M. Co

130.000

C. Dawson, trustee

122.560

Skelton No. 1

87.890

Lucky Kid M Co

85,350

80,880

Central L. & Z. Co

117,540

Lion M. Co

115,690

Piokee L. & Z. Co

83,960

Lucky Bill M. Co

80,000

Dewdrop M. Co

87.080

ITaynes M Co

78,970

2,860

Woodchuek M. Co

54.360

Croesus M Co

'85,960

Blue Goose M Co

65,440

Sundries

243.220

478,360

Leases us- tally provide for the removal by the lessee of all machinery and equipment at the expiration of his lease, and as the standard practice of the district in both mining and milling is adaptable in all mines it enables an operator to salvage and transport the machinery of h, i mill, hoisting and other equipment almost intact to another part of the district and continue operations on a new tract under a new lease.

Ores and concentrates are sold at the mills through ore-buying agencies representing the various smelters, according to the time-honored custom of the district, at so much per dry ton. For zinc sulphides the base price per ton is quoted by the buyers for a 60% zinc metal content and is subject to fluctuation according to the market price for spelter and special characteristics of

In the Joplin district grades of ore mined are considered in terms of base grade concentrates made. Thus a 2% ore is understood to mean one from which 100 tons would produce at the mill 2 tons of combined concentrate of the base grades given. Zinc concentrates vary in grade in different parts of the district from 50 to 65% metal, and lead concentrates from 70 to 83% metal.

Separate 'description of the many independent operations in the Joplin district is not necessary, as their number is great and the difference slight; but reference to the holdings of some of the larger companies is of interest. The American Zinc, Lead and Smelting Co. holds in fee thousands of acres in groups located north of Joplin, Webb City, Carterville and Oronogo, and south of Joplin in small scattered tracts extending from the Oklahoma line to Granby and including the properties absorbed in 1816 of the Granby Mining and Smelting Co., and recent acquisitions along the western border of present activities in the Kansas field. In the Oklahoma section the most important producer is the Eagle- Picher Lead Co., with rich and extensive tracts leased and sub-leased at Picher, Cardin and south of Tar Eiver.

The Miami Zinc Syndicate has leases aggregating 4000 acres in tracts under development west of Baxter Springs in Kansas ; and the American M etal Co. has a vast number of small tracts in the northwestern part of the Missouri section and extending from northeast to southwest across the Kansas section along the so-called Miami fault belt. The properties of the Commerce Mining and Eoyalty Co. lie mostly in the Miami field to the west of Miami, Century and Picher, extending along the Miami fault belt into the southern part of Kansas. This company was the first in the western -fields, having struck ore at Commerce in 1905. The Vinegar Hill Zinc Co. has a comparatively smaller tract west of Baxter Springs

According to the annual statistics published by the Journal, the production in ores and concentrates of the Joplin district in 1917 was 550,000 tons. Of this amount 80% was as blende, 6.5% calamine, 13.5% galena. Missouri produced 58.5% of the total tonnage, Oklahoma 34% and Kansas 7.5%. Considering the proportional production of total blende ores, which was 442,- 000 tons, Missouri accounted for 56%, Oklahoma 36% and Kansas 8%. Most of the calamine came from Missouri mines and amounted to 35,695 tons, Oklahoma producing only 65 tons and Kansas none. Of the lead ores produced, which altogether amounted to 72,500 tons, Missouri yielded 55%, Oklahoma 39%, and Kansas 6%.

In each of the four years since 1913 production from the Joplin district responded to advancing prices of zinc; and although in 1917 zinc concentrates averaged only $67.70 per ton with zinc at 8.7c. per lb., as compared to $84.72 in 1916 with zinc at 12. 5c. and $79.30 per ton in 1915, when zinc was 13c. per lb., Joplin increased its production nearly 26% over that of 1916.

FIG. 8. PANORAMIC VIEW OF PICKER, OKLA., SHOWING THE MOST ADVANCED and west of the Commerce company's properties, and the U. S. Smelting Co. has developed and completed a large mill on tracts west of the Vinegar Hill ground, and holds some leases northeast of Waco. Other large development enterprises in the district are : The Chanute Spelter Co., with 16,000 acres: the Butte and Superior; the Waco Mining Co., with 71,000 acres; P. B. Butler, with 6500 acres; the Danglade, and the Church & Mabon interests. The most important producers at present are those given in the table, grouped according to their respective camps and showing the relative production in various classes of ores and concentrates as officially reported for the week ended Oct. 20, 1917. The base range of prices for ores and concentrates for the week was: Blende, from $60 to $75, with an average of $67.50 and an average settlement price of $66. Galena was sold in prices ranging from $70 to $80 per ton and calamine $35 to $38 per ton.

Zinc silicate ores are mined in certain parts of the district, as at Granby, Duenweg and Joplin City. Granby is the chief producer, and in 1916 averaged about 50 tons per day. The American Zinc, Lead and Smelting Co. is at present producing from its own and sub-leased properties in Granby about 40 tons of this ore per day. But little lead-oxide ore is found. The average rate of production in silicate ores from all camps is about 75 tons per day.

The annual increase over the preceding years in 1916 was 23% and in 1915, 12',. Considering the production in 1914 as normal compared with previous years since 1900, when prices of zinc concentrates ranged between $40 and $45 per ton and spelter between 5 and 6c. per lb., the production of 1917 was 60% greater than in normal pre-war years. Lead ores reached the highest average basic price in 1917, which, roughly, was $98 per ton, as compared wilh $S i in 1916, $55 in 1915, $46.50 in 1914 and $52.50 in 1913. Although an important byproduct of the Joplin district, lead is produced in comparatively small quantities, and the fluctuations of the price of zinc practically govern operating conditions, irrespective of the price of lead.

The response to the demands of the war, reflected in the increased prices of zinc and lead, was made possible by the exploration of lower-grade ores in the Missouri sheet-ground mines and the rapid expansion of developments in the Oklahoma and Kansas high-grade fields. The last six months of 1917 witnessed a strong reaction in metal and concentrate prices, and many mills operating on low-grade sheet-ground ores were forced to cease operations. A large percentage \\erc dismantled and taken to the newer fields. As a consequence, this condition decreased the 1917 production of blende from Missouri about 9%. The production of lead and calamine was slightly increased. Tn Oklahoma and Kansas

TILE UIXIXG DISTBICTS OF JOPL1X AXD SOUTHEAST MlSSOl'HI many developments started in 1915 and 191C reached their productive stages early in 1917, and notwithstanding the drop in metal prices later in the year, this section of the district continued its intensive production and was only prevented from making greater gains by shortages of labor and power. The increase in production of blende from Oklahoma and Kansas in 1917 was 175% and of lead 94% of the production of 1916.

The orebodies of Joplin, as mentioned, occur in all Carboniferous sedimentaries of the district, but mainly in the cherty crystalline Boone limestone of Mississippian age. The Boone outcrops throughout all but the extreme western limits of the district, has a total thickness of 350 ft. and a slight regional dip somewhat north of west, disappearing in the Oklahoma and Kansas sections and at the northwest corner of Jasper County, Mo., under the overlying and successively outcropping Chester and Cherokee limestones, sandstones and shales, respectively of Mississippian and Pennsylvanian age. Two distinct classes of orebodies occur in the Missouri section, and the present mines, are much lower in grade, yielding in 1916 mill recoveries, in the orebodies then worked, ranging from 1% to 3% combined sulphides. At present 2% ores are barely yielding a margin of profit.

In many places the sheet-ground orebodies are continuously connected to the sink-hole deposits above by orebodies occurring in the upper Boone. Such orebodies also are replacements and deposits in and upon the limestone walls of former openings or channels. The mineralization has in some places been followed in mining for varying distances below the sheet-ground deposits in what is known as the " second lime." Camps where the mining of " upper run " orebodies still exists are Duenweg, Joplin and Granby. The largest sheet-ground mines are at Webb City, Carterville, Joplin, Duenweg, Porto Eico and Granby. The " lower run " orebodies have been mined at Orongo, Sarcoxie, Aurora and Cave Springs. At Granby and Springfield ore has been mined from the " gumbo runs " or deposits in the basic shales of the Boone formation.

OPERATIONS AND THE INTENSITY OF DEVELOPMENT IN A PERIOD OF Two YEARS.

locally these are known as the " upper run " and the " sheet-ground " deposits. The " upper run " deposits were the earliest found, occurring near the surface in the higher horizons of the Mississippian limestones, mainly in the bouldery ground along the roughly semi-spherical contact made by the deposits of the later shales in ancient sink holes in the Chester and Boone. The sheet-ground deposits occur in a cherty stratum of the Boone known as the Grand Falls chert, that lies in nearly horizontal position about 250 ft. below the surface and from 50 to 100 ft. from the lower shale base of the Boone formation.

The Grand Falls chert has a thickness varying from eight to 50 ft. The sulphides occur as. replacements of the lime and deposits in openings, disseminated in a cherty breccia and laminated in roughly horizontal seams intercalated between alternate narrow bands, or sheets, as the name implies, of chert, flint and jasperoid. The Grand Falls chert is seldom mineralized for more than 20 or 25 ft. vertically, the orebodies being inclosed above and below by barren zones of flint of varying thickness; but these deposits extend over wide areas in many parts of the western portion of the Missouri section, and most typically and persistently in the zone, shown on the accompanying map, between Oronogo and Duenwpg. The sheet-ground deposits, although far more extensive and productive than the "upper run'" deposit-;, especially in

In the Miami district definite geologic relationships are not so apparent and have not as yet presented sufficient evidence for complete and satisfactory conclusions. Two distinct ore horizons or " runs," however, are recognized. The " lower run," which to date is the most important both in grade and size of the orebodies, lies at depths ranging from 250 to 300 ft., and in shape, thickness and general dip and strike presents characteristics similar to the sheet-ground deposits of Missouri, without, however, having the sheets of flint characteristic of the Grand Falls dhert. In the Miami orebodies the mineralization is considerably higher in grade than in the sheet-ground mines and generally presents more of a disseminated structure. There is more limestone in the gangue of the orebody, and considerable yellow calcite or " tiff " ; and although much of the ore occurs in tabular narrow seams, and considerable flint and chert are present, the formation in the mineralized areas so far mined appears to be more extensively of the brecciated and rec-emented type, and on the whole presents decided marks of distinction from the structural characteristics of the sheet-ground orebodies. The richest ores have been concentrated along bedding planes and parallel watercourses where a sheeted condition exists, and may represent horizons which, according to Siebenthal, are at the terminus of an artesian circulation controlled by the imprevious shales which begin to outcrop