ties. To obtain and check the records of production of minerals from the leased lands and to report at the end of each quarter the amount of production and the value of accrued rentals and royalties chargeable to each lease.

§ 231.4 General obligations of lessees.

Mining operations by the lessee shall conform to the terms of the act, the lease, and the regulations in this part and to the written instructions of the mining supervisor and his subordinates, and shall use all reasonable precautions, in accordance with the most approved methods, to prevent waste, damage to mineral-bearing formations, and injury to life or health, and shall provide for safety and welfare of the employees. MAPS AND PLANS

§ 231.5

Maps and plans required prior to beginning commercial operations; modification thereof; departure therefrom; operations in advance of approval thereof or not in conformity therewith.

Prior to the beginning of actual commercial mining operations maps and plans showing the proposed mining methods and the plant layout shall be submitted to the district mining supervisor for approval. Such maps and plans shall be modified as required by the district mining supervisor, and when approved shall be put into execution. If subsequent operations require radical departure from the approved maps and plans, supplementary maps and plans shall be submitted with a statement of reasons for the changes. Operations conducted in advance of approval of such maps and plans by the district mining supervisor or not in conformity with approved maps and plans constitute violation of the regulations in this part. § 231.6 Requirements for maps of underground workings and surface operations and equipment; accuracy to be attested before notary public; posting.

Maps of underground workings, unless otherwise ordered by the district mining supervisor, shall be drawn to a scale of 100 feet to the inch; maps of surface operations and equipment may be to a scale of not over 200 feet to the inch. All maps shall be appropriately marked with reference to Government landmarks or lines and elevations with refer

ence to sea level. Where the beds or deposits dip at angles greater than 45° from the horizontal, vertical projections and cross sections shall be made accompanying plan views. Maps shall be based on accurate surveys made within 30 days following January 1 and July 1 of each year and as may be necessary at other times. Accurate copies of such maps on tracing cloth or prints shall be furnished the district mining supervisor when and as required. The accuracy of maps furnished shall be attested before a notary public. The maps shall be posted to date at least once each six months.

§ 231.8

PROSPECT BORE HOLES

Submission of core or test hole records; cores, samples, cuttings, mill products; cementing and casing of drill holes.

The lessee shall submit promptly to the district mining supervisor sworn copies of all core or test hole records made on the leased lands, the records to be in such form that the position and direction of the holes can be accurately located on a map. The records shall include a log of all strata penetrated and conditions encountered, such as water, quicksand, gas, or unusual conditions, and copies of analyses of all samples analyzed from strata penetrated shall be transmitted to the district mining supervisor as soon as obtained. The core from test holes shall be available for inspection at the convenience of the district or deputy mining supervisor, and he shall be privileged to cut such cores and receive samples of such parts as he may deem advisable, or on request of the district mining supervisor the lessee shall furnish such samples of strata, drill cuttings, and mill products as may be required. Drill holes for development or

holes for prospecting shall be cemented and cased to the satisfaction of the district mining supervisor and in a manner not to endanger any present or future underground operation or any deposit of oil, gas, or other mineral substances.

WELFARE AND SAFETY

§ 231.9 Sanitary, welfare, and safety arrangements.

The underground and surface sanitary, welfare, and safety arrangements shall be in accordance with the recommendations of the United States Public Health Service and United States Bureau of Mines.

CROSS REFERENCES: For United States Bureau of Mines, see Chapter I of this title. For United States Public Health Service, Department of the Treasury, see 42 CFR Chapter I.

§ 231.10 Reports of accidents, inundations, or fires to be promptly mailed; fatal accidents and serious or threatening damages to be reported by telegraph or telephone.

Full reports of all accidents, inundations, or fires shall be promptly mailed to the district mining supervisor by the lessee or his representatives. Fatal accidents and serious or threatening damages to the mine, the leased lands, or deposits, shall be reported to the district mining supervisor by telegraph or telephone.

§ 231.11 Protection of employees; mechanical equipment; dangerous walks or passages; moving parts of machinery or belts.

All employees while in the mine or accessory plants shall be afforded all possible protection to life and health. All mechanical equipment used for the transportation of men shall be of a safe design and character for the work it performs. At dangerous walks or passages adequate shelter holes shall be made, guard rails or fences shall be erected, and warning signs shall be posted. All moving parts of machinery or belts, when endangering employees or liable to result in injury, shall be adequately guarded.

The lessee shall observe good practice in prospecting and mining, sinking wells, shafts, and winzes, driving drifts and tunnels, stoping, blasting, transporting ore materials, hoisting, the use of explosives, timbering, pumping, and other operations for the development and preservation of any operation, mine, or mine equipment on the lease. § 231.13 Operations shall be conducted in a manner to yield ultimate maximum recovery; information recorded and copy furnished district mining supervisor.

Mining operations shall be conducted in a manner to yield the ultimate maximum recovery of the mineral deposits. All shafts, main exits, and passageways, as well as overlying beds or mineral deposits that at a future date may be of economic importance, shall be protected by adequate pillars in the deposit being worked. Information obtained regarding the mineral deposit being worked and other mineral deposits on the leased lands shall be fully recorded and a copy of the record furnished to the district mining supervisor.

§ 231.14 Sufficient pillars shall be left.

Sufficient pillars shall be left in first mining to insure the ultimate maximum recovery when the time arrives for the removal of pillars. Boundary pillars shall in no case be less than 50 feet thick unless otherwise specified in writing by the mining supervisor. Boundary and other main pillars shall be mined only with the written consent or by order of the mining supervisor or his authorized subordinates.

§ 231.15 Working places; traveling way.

All working places shall be visited at least once during each shift by the mine foreman or his assistants, and there shall be provided adequate timber distributed throughout the mine for the usual daily uses. The roof and sides of every traveling way and each working place shall be made secure when neces

sary by timbering or adequate lining and arching in accord with good mining practice and the lessee shall not permit anyone to travel on or work in any traveling way or working place which is not secure, unless appointed for the purpose of exploring, inspecting, or repairing

same.

§ 231.16 Mining or prospecting minerals soluble in water; brines; minerals taken in solution.

In mining or prospecting deposits of potassium or other minerals soluble in water, all wells, shafts, prospect holes, and other openings shall be adequately protected with neat cement against the coursing or entrance of water; and the lessee shall, on orders of the district mining supervisor, back fill with rock or other suitable material to protect the roof from breakage when there is a danger of the entrance of water. On leased lands containing brines, due precaution shall be exercised to prevent the deposits becoming diluted or contaminated by the mixture of water or valueless solution; and, where the minerals are taken from the earth in solution, such extraction shall not be within 500 feet of the boundary line of the leased lands without the written permission of the Secretary of the Interior.

PROTECTION AGAINST MINE HAZARDS § 231.17 Dust, fumes, and acids.

In

In the mining and milling or treating of the ores or mined products, the employees shall be adequately protected from injurious fumes, acids, dusts, and harmful or dangerous conditions. mines where siliceous or other harmful dusts are formed, drilling machines shall be of the water-injection type and sprays shall be used to wet down the dust.

§ 231.18 Ventilation.

Lessees shall provide and maintain for each underground operation on any lease a good and sufficient amount of ventilation for such men and animals as may be employed therein, and shall cause an adequate quantity of normal air to circulate through and into all the shafts, winzes, levels, and all working places of such mine. A working place, entry, or passageway shall not be deemed normally

in a fit condition for men to work or travel in if the air therein be found by chemical analysis to contain on a moisture-free basis more than 14 percent carbon dioxide or less than 191⁄2 percent oxygen. The lessee, upon being notified of such finding, shall immediately undertake measures to improve the quality of the air of said working place or entry. Where natural ventilation does not furnish a positive current of air, ventilating fans shall be provided. Fans when installed shall have fireproof housing and surface fans shall be so arranged that the ventilating current can be quickly reversed.

§ 231.19 Inflammable gas and dust.

Mines in which inflammable gas is found or explosive dust produced shall be subject to the coal-mining operating regulations covering these hazards.

CROSS REFERENCE: For coal-mining operating regulations, see Part 211 of this chapter.

The lessee shall store, thaw, transport, issue, and use explosives only in the most approved manner and with due regard for the safety and welfare of the employees and protection of property and in accord with instructions or notices issued by the district mining supervisor. § 231.21 Electricity.

Electric circuits with potential of more than 600 volts shall be conducted in or through a mine only through insulated lead-covered armored cables, with the armor electrically continuous throughout and grounded, and may only be used for transmission or for application to transformers, motors, or other apparatus in which the whole of the high-voltage winding is stationary. Electric circuits of between 300 and 600 volts may be used only for stationary motors. All portable motors, such as locomotive mining machinery and portable pumps or portable fans, shall use current of less than 300 volts. All electric wires and appliances shall be installed, maintained, and used so as to insure safety to the employees and the mine and be in accord with the recommendations of the United States Bureau of Mines.

§ 231.22 Fire protection.

All structures within 75 feet of any mine opening shall be so constructed and protected against fire that the men in the mine shall not be endangered if fire should occur in a surface building. Inflammable material shall not be stored within 75 feet of a mine exit. All shafts shall be fireproof. All underground offices, stations, shops, magazines, and stores shall be so constructed, equipped, and maintained as to reduce the fire hazard to a minimum. Sufficient firefighting apparatus shall be maintained in working conditions at the mine exits and at convenient points in the mine workings for fire emergencies. An adequate water supply shall be held in storage tanks or reservoirs for fire emergencies and be available for immediate use through connecting pipe lines for either surface or underground fires. § 231.23

Escape ways.

In all underground operations the lessee shall not without the written consent of the district mining supervisor employ more than 10 men underground on any one shift until a second exit or escape way of adequate dimensions has been made from the interior of the mine to the surface. At the surface such exits shall be not less than 100 feet apart if by drift nor less than 200 feet apart if by shafts. When necessary in the opinion of the district mining supervisor such escape ways shall be provided with ladders or stairs in addition to any mechanical means of ingress or egress as may exist or be required. Said openings shall not be covered by or connected with inflammable buildings or materials, but open timber framework may be permitted.

MILLING; WASTE FROM MINING OR
MILLING

§ 231.24 Milling shall be in accord with approved practices.

It shall be the duty of the lessee to use due diligence in the reduction, concentration, or separation of mineral substances by mechanical or chemical processes, by distillation, by evaporation, or other means so that the percentage of salts, concentrates, oil, or other mineral substances recovered shall be in accord with the most approved practices.

§ 231.25 Disposal of waste from mining or milling.

The lessee shall make such provision

for the disposal of the waste from wells, the waste rock from the mines, the material removed in hydraulic or stripping operations, the sludge from the mill, the brines from the plant, and other refuse that it will not become a nuisance or obstruction to any public highway, railroad, right of way, or other avenue of transportation or travel, or to any private or public land or stream, or in any manner to occasion private or public damage.

PRODUCTION RECORDS AND AUDIT

§ 231.26 Books of account to be kept.

The lessee shall maintain books in which will be kept a correct account of all ore and rock mined on the tract, of all ore put through the mill, of all mineral products produced, and of all ore and mineral products sold and to whom sold, the weight, assay value, moisture content, base price, dates, penalties, and price received, and the percentage of the mineral products recovered and lost shall be shown.

§ 231.27 Sale price basis not less than highest market price; Secretary of the Interior may determine and declare market price.

The sale price basis for the determination of the rates and amount of royalty shall not be less than the highest and best obtainable market price of the ore and mineral products, at the usual and customary place of disposing of them at the time of sale, and the right is reserved to the Secretary of the Interior to determine and declare such market price, if it is deemed necessary by him to do so for the protection of the interests of the lessor.

§ 231.28

Audit of lessee's accounts and books semiannually or at other times; lessee to furnish audit free of cost.

An audit of the lessee's accounts and books may be made semiannually or at such other times as may be directed by the Secretary of the Interior, by certified public accountants, approved by the Secretary, and at the expense of the lessee. The lessee shall furnish free of cost a copy of such semiannual or other audit to the Secretary of the Interior, through the duly authorized representative of the Department of the Interior, within 30 days after the completion of each auditing.

INSPECTION, ISSUANCE OF ORDERS AND ENFORCEMENT OF ORDERS

§ 231.29 Lessees shall provide means for inspection of underground and surface conditions; surveying, estimating, and study.

The lessees shall provide means at all reasonable hours, either day or night, for the district mining supervisor, his subordinates and representatives, and for Federal mine surveyors authorized in writing by the district mining supervisor for the purpose of inspection of underground and surface conditions, surveying, estimating amount of ore or mineral product mined, and to study the methods of mining that are or were followed.

§ 231.30 Issuance of orders.

Before beginning commercial mining operations the lessee shall inform the district mining supervisor in writing of the designation and post-office address of the mining operation, and of the name and post-office address of the superintendent or other agent who will be in responsible charge of the mining and milling operations and the sanitation and welfare of the employees on the leased land, and who will act as the local representative of the lessee. The district mining supervisor shall also be informed of each change thereafter in the address of the mine office or in the name or address of the local representative.

mine or mine office, or mailed or handed to the superintendent, the mine foreman, the mine clerk, or higher officials connected with the mine, for transmittal to the lessee or his local representative. § 231.32

Enforcement of orders; suspension of operations; temporary waiver of suspension order pending appeal and review.

If the lessee fails to comply with the regulations in this part or any part thereof, or with any orders or instructions of the mining supervisor or his authorized subordinates, the district mining supervisor shall have authority to require him by written order to suspend any or all operations on the leased lands. This suspension shall remain in force until the lessee complies with the regulations or orders that have been violated or until such order of suspension has been revoked: Provided, That if the continuance of any such operation required to be suspended does not endanger life, threaten immediate, serious, and irreparable damage to the mine or the deposit being mined, or other valuable mineral deposits, the district mining supervisor, on petition in writing made by the lessee within 10 days from the issuance of the order of suspension, shall temporarily waive compliance with the order of suspension pending an appeal to and review by the Secretary of the Interior.

§ 231.33 Appeal; time allowed.

Any appeal must be filed in duplicate with the district mining supervisor for transmittal to the Secretary within 30 days from the issuance of the order of suspension.