TID-4500, UC-35 Nuclear Explosions — Peaceful Applications

L5 LASA/RENCE UVERMORE LABORATORY Unh*^atCa*xrik/UmrnK^Cm>nl4/94550

UCRL-51163 POSSIBLE EFFECTS OF THE RIO BLANCO PROJECT ON THE OVEkLYING OIL SHALE AND MINERAL DEPOSITS F. Holzer D. O, Emerson MS. date: December 27, 1971

— NOT.CE- Thlt report was prepare? «*i an account of work sponsored by the United States Government. Neither the United States no? tha United States Aiomic Energy Commission, nor any/ of sheir employees, nor any of

their contractors, subcontnctors; or their employees, maJcai vat 1*f*«M*y, »*gs«s,«s irnqKaA, « mawata any lags] liability or responsibility for the accuracy, com­ pleteness or usefulness of iny {information, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights.

wawsimw OF THIS oocumm is ONI Contents

Abstract 1 Introduction 1 The Hio Blanco Project and Site Geology 3 Proposed Phases of the ?roject 3 Subsurface Geology and Mineral Distribution 6 Stratigraphy 6 Mineral Distribution ~i Hydrology 10 Effects of Rio Blanco 10 Subsurface and Near-Surface Effects 10 Explosion-Induced Fault Motion 20 Effects on Mines 22 Summary 25 Acknowledgments 25 References 26

•iii- POSSIBLE EFFECTS OF THE RIO BLANCO PROJECT ON THE OVERLYING OIL SHALE AND MINERAL DEPOSITS

Abstract

The proposed Rio Blanco nuclear deto­ We expect no subsurface separation of the nation for stimulating natural gas produc­ rock layers in the Green River Forma­ tion (and the subsequent development of tion. A seismic reflection survey shows the Rio Blanco Unit) has raised questions that the closest indication of a subsurface about possible harmful effects of the ex­ fault occurs about 2 miles from the Rio plosions on the overlying formations con­ Blanco location. Data from the Nevada taining oil and sodium minerals. We Teat Site show that no fault farther than show that fractures will extend to perhaps 6000 ft from a 100-kt explosion would 400 ft above tht> upper explosive. Since undergo explosion-induced displacements, at least 2300 ft separates the gas-bearing and hence none is expected from Rio strata from the oil shale and minerals, Blanco. At the mine closest to Rio no fractures will extend into the forma­ Blanco, we predict the peak acceleration tions containing these resources. We to be 0.06 g. Since this was about the calculate a spall depth of about 170 ft; same acceleration experienced by this our experience indicates that no harmful mine from the Rulison explosion, Rio effects will occur as a result of this spall. Blanco should not cause any mine damage.

Introduction

As part of the Plowshare Program's tial phase are now being defined, and the use of nuclear explosives to stimulate environmental impact is being studied. the recovery of natural gaa from low- The progress of the plans for the first permeability formations, the CER- phase of the Rio Blanco Project, as well Geonuclear Corporation, together with as for the subsequent unit development, the Equity Oil Company, has proposed has raised concern among various corpo­ a project whose initial phase consists of rations that are attempting to develop the simultaneous detonation in a single economic techniques for recovering oil emplacement well of three 30-kt nuclear and other minerals from the oil shale explosives in the Fort Onion and deposits that are distributed in various Mesaverde Formations of Colorado's amounts in different parts of the Piceance Piceance Basin. The details of this ini- Basin,2 Emplacement well

Parachute Greek Member Green River Formation (oil shale and minerals)

7MZL -Orange Marker

2900 3000 --

4000 -- Wasatch Formation

5000 -- 53«)

Fort Union Formation Oil shale 6000 (>I0gal/ron) 6180

Gas-bearing Mesaverde Formation sandstone 7000 H

Fig. 1. Generalized geological cross section at the Rio Blanco site showing the main gas-bearing formations as well as oil- and mineral-containing formations. Depths indicated are in feet; the horizontal scale is equal to the vertical scale.

-2 Our approach is to examine the poten­ 4) Explosion-induced motion on exist- tial impact of Rio Blanco on the geologic ing faults. formations containing the oil and the 5) Damage to existing mines. sodium minerals nahcolite and dawsonite. Figure 1 shows the relation of the pro­ The premise on which the conclusions are posed Rio Blanco Phase-1 project to the based is that if these formations are not geologic formations containing oil shale fractured as a result of the explosions and minerals. The gas-bearing forma­ or attendant phenomena, then the re­ tions that are planned for nuclear stimu­ covery of the oil and minerals will not lation lie, in general, at a depth greater be affected. than 5000 ft, while the oil shale and We examined the following possi­ mineral-containing rocks are, in general, bilities: encountered in the 400- to 3000-ft interval. The main conclusion reached from the 1) Direct fracturing from the explosion studies presented in the following sections zone into the oil shale and the for­ is that the separation of more than 2300 ft mations bearing sodium minerals. between the detonation zones and the 2) Extent and depth of surface fractur­ mineral-containing formations serves ing or "spall." as an effective barrier between them and 3) Subourface separation of the various makes any disturbance of the latter highly strata and layers. unlikely.

The Rio Blanco Project and Site Geology

The location of Phase 1 of the Bio Blanco simultaneously, the details of the Phase-2 Project, as well as th

-4- j|g^y^ ® Rio Blanco Phase-1 location kfe- O ApProx'mate Phase-2 location

Fig. 3. Location of the Rio Blanco Unit within the Piceance Creek Basin. Tht Phase-2 locations snown are approximate only. -5- simultaneous detonations should net be scription of these topics is necessary to ruled out at this time. evaluate the potential impact of the Rio Phase 3 is presently contemplated to Blanco Project. consist of 20 to 60 well stimulations whose Figure 4 depicts a cross section of the nature and location will depend on the re­ subsurface geology along a;i approximately sults from the previous phases. A more east-west line through the Rio Blanco em­ extensive development of the unit, con­ placement well, and Fig. 5 shows the sisting of stimulating perhaps an addi­ cross section in a generally northeast- tional 100 wells, would follow. southwest line for the western portion of the unit. These figures show that the beds SUBSURFACE GEOLOGY AND MINERAL dip and thicken from west to east and from DISTRIBUTION south to north. Generally, the Evacuation The general subsurface geology and Creek Member of the Green River Forma­ mineral attribution of the Piceance Creek tion is exposed at the surface. However, Basin have been studied extensively and are the Parachute Creek Member outcrops in 3 described in the literature. We will not the extreme southwestern corner. attempt to duplicate this information here Stratigraphy but will focus our attention instead on the The stratigrapbic horizons observed Rio Blanco Unit, for which a brief de­ near the emplacement well for Rio Blanco

6000 ft ~-~^-"ir-- Mahogany Zone-* _ m . _2range_Mar|(er (Base of lean oil shale) 4000 ft

2000 ft

Sea level West last

Fig. 4. Geologic cross section along a general east/west line through the Rio Blanco Unit and the Phase-1 emplacement well. 6000 ft

"TCFarige Marker 4000 ft (Base of lean oil shale)

2000 ft

Sea level Southwest Northe st

Fig. 5. Geologic cross section from southwest to northeast of the western par. of the '. io Blanco Unit.

are at a depth that is about average for the Formation, a mudstone and shal J unit unit. At that location alluvium deposits containing intermitteat and infr* quent in the stream bed are found bet'veen the lenses of sandstont carrying g 9 and surface and a depth of about 100 ft. Be­ water, extends from about 3000 to 5360 ft. tween 100 and 400 ft below the surface is Below this level are gas-bearing sands of found the Evacuation Creek Member of the Fort Union and Mesaverde Formations the Green River Formation—a barren in which the proposed nuclear detonations sandstone, siltstone, and mudstone forma­ will take place. tion. The Parachute Creek Member of the Green River Formation, a marlstone, Mineral Distribution contains most of the oil shale and sodium Figure 6 shows the areal distribution 4 minerals and extends from a depth of of the oil shale. It can be seen that the 400 to about 2100 ft. The so-cs-Ued greatest yield and thickness of oil shale Mahogar^ Zone, about 180 ft thick, is is found near the center of the basin north found between 760 and 940 ft. The Green of the proposed gas stimulation unit. In Eiver Formation emends to about 3000 ft, addition to oil shale, other minerals of but the interval between 2300 and 3000 ft concern include nahcolite (sodium bicar­ contains, on the average, less than 3 gal- bonate) and dawsonite, an aluminum- 4 Ions of oil per ton oi rock. The Wasatch containing mineral. These minerals, -7- R100W R99VV R98W R97W R96W R95W R94W R93W

R101W RIOOW R99W

R95W R94W R93W R96W

Fig. 6. Isopach map of oil shale in the Piceance Creek Basin and the Rio Blanco Unit.4 Also shown is the U. S. Bureau of Mines/AEC Core Hole #3. The numbers on the contours give the maximum thickness (in feet) of continuous section averag­ ing 25 gallons of oil per ton. HCI-extractable Oil yield — gal/ton Nahcolite content — wt% alumina — wt% 0 10 20 30 40 50 0 10 20 30 40 50 60 1900 0123456 i r—i r I J, I I

2000

2200

2400

2500

2600

2700 "Core missing J I I L

Fig. 7. Oil yield, nahcolite content, and HCl-extractable alumina in the Colorado Core Hole #3 as determined from cores spanning the nahcolite-containing strata.

-9- having a geologic origin similar to that shale averages 2.7%, with a maximum of of the oil shale, are similarly dis­ 5.8%. tributed. N&hcolite inclusions sev­ Hydrology eral feet in diameter have been The hydrology of the Fawn Creek site found. By contrast, dawsonitf> is fine has been determined, and a preliminary grained and much more uniformly analysis is available. Water is present distributed. from within 47 ft of the ground surface to A quantitative uetermination of nahcolite a depth of approximately 1550 ft. The and dawsonite concentrations in the static water level associated with the Piceance Basin has been reported by zones above and below the Mahogany Zone 5 Smith and Young on cores spanning the differ by about 8 ft. The water production entire nahcolite-bearing section of the from the lower zone is only about 200 gal/ U. S. Bureau of Mines/AEC Colorado Core day/ft, which indicates a rather ':ight Hole #3. The location of this hole, shown formation at this site. Wells drilled in Fig. 6, is about 18 miles north of the throughout the unit show that the water­ Rio Blanco site and about 10 miles north bearing zones of the Green River Forma­ of the closest unit boundary. The results, tion are not connected with the connate shown together with oil content in Fig. 7, water of the Fort Union and Mesaverde indicate an average nahcolite content of Formations. In the Wasatch Formation 22.4%, although in thin layers the concen­ are found only infrequent and widely tration is as high as 48.3%. The amount spaced lenses containing water together of Al-O, that is acid-leachable from the with some gas.

Effects of Rio Blanco

SUBSURFACE AND NEAR-SURFACE matelyl200 to 1300 ft of gas-bearing EFFECTS 7 formation is expected to be formed. The description of the Rio Blanco det­ Figure 8 shows this configuration. onation effects can be conveniently sep­ The radius of the fractured zo.-e is ex­ arated in terms of effects below the pected to be approximately 70 ft, with Green River Formation and effects in and fractures radiating horizontally to approx­ above that formation. The three nuclear imately 350 ft from each detonation point explosives will be emplaced in the same and extending to perhaps 400 ft above the hole and detonated at approximately 5875, highest explosive location. These pre­ 6340, and 6775 ft below the surface. The dictions are based on experimental ob­ spacing of 420 to 450 ft is based on the servations of the effects of nuclear explo- Q expectation that the chimney from a sions at the Nevada Test Site, postshot 9 single 30-kt explosion would extend about investigation of the Gasbuggy and 350 ft above the level of the detonation; Rulison detonations, as well as theo- with a spacing of 450 ft a continuous retical calculations. 11 Contrary to what high-permeability zone spanning approxi- has been surmised at various times,

-10- Rulison chimney; Figure 10 shows the Gasbuggy chimney and the surrounding fracture field, as determined from the postshot drilling and gas production data. 5400 Figure 11 gives the data from direct measurements of the fracture formation at the Gasbuggy Site; the measurements 5600 show that a very weak electrical cable remained intact for all distances greater 9 than 440 ft from the detonation center. 5800 These observations, together with others from the Nevada Test Site, have shown that fractures extend, in general, 6000 to ranges less than about five times the radius of the final explosion cavity. Figure 12 summarizes these observations

6200 B lor a variety of rock types, Since the predicted cavity radius from each 30-kt Rio Blanco explosion is estimated to be 6400 about 70 ft (the 29-kt Gasbuggy explosion at a shallower depth gave a cavity radius 6600 of about 78 ft), no fracturing is expected farther than about 350 or 400 ft from each explosive. Since throughout the 6800 ' V proposed Rio Blanco unit the detonation points will be more than 2300 ft below the bottom of the oil shale and mineral- bearing formations, direct fracturing Fig. 8. Chimney and fracture zone de­ tails expected from Project Rio from the explosion should not be able to Blanco. penetrate to these deposits. The Rio Blanco explosions will give fracturing from a nuclear explosion is rise to a strong shock wave that degen­ confined to a relatively small region. erates rather rapidly, but when it arrives Permeability measurements derived at the surface its amplitude will still be from the 2as flow data on both Gasbuggy considerable. Therefore, we investigated and Rulison indicate that no fractures the potential effect of this stress wave on could have extended more than approxi­ the Green River Formation, using calcu­ mately 300 to 350 ft from these lation procedures developed with the aid detonations. of the previously cited experimental Chimney heights have been found to observations. correlate closely with fracture dis- When the compressional wave is re­ 1 2 tances. Figure 9 is a schematic of the flected from the ground surface, it does 11- Emplacement Reentry Exploration 600 ft •>'-"'Y,SlJ-> '••

500 ft

400 ftU

300 ft jj • ''i* i ii • iji I*. * . i', '-i '• • " «l >- ~*~-", r •"•• •'

200 ft

100 ftr- I? c vi £ x Oft o £• 8

-100 ft r-

-200

*r*jj Gas sands

• Shales

Fig. 9. Rulison postshot interpretation based on cores, logs, gas composition, and gas production. The cavity radius was 76 ft, the depth of burial was 8427 ft, tnd the yield was 43 kt.

-12 Feet >j 100 200 300 400 1 1 1 1 Depth 3464 In feet 3500

UJ CO CM Ojo % 4*1 0 7 1 CD HI CO at Alamo O o 5 ^1 o s 3600 3637

. Kirtland - 3700

1 !• 3796 Si* 3800 _ 1 Fruitland i i J * 3862

3900

4000

4100

4200

4300

14400 To 4800 To 4600

Fig. 10. Gasbuggy postshot interpretation and geophysical data.

13 so as a tension wave, and separation of nations at the Nevada Test Site. The the su. face material can occur. This depth of this disturbance is greatest when phenomenon, called spall, has been ob­ the material has no tensile strength; a served and studied on a number of deto- calculation based on 100 kt detonated at -13- 3700 1 1 1 ' 1 1 1 1 1 2}Measured points; the triangles represent less certain dota. Points connected by dashed line are equally probable. 3800 -

3900 - * —t- 7~ - Calculated j - \ / O 4000 _ arrivatimesl -\ ><\ri \ vt En/ d of intact fracture _ e y^ cable in GB-1 o/ £ 4100- -

4200 -

4300, .1 1.1 1 1 1 1 1 1 10 20 30 40 50 40 70 80 90 100 Time — msec Fig. 11. Dynamic shock and fracture formation measured for Gasbuggy. The horizontal lines indicate sections of the electrical cable that was progressively shortened by breaks from the bottom. The cable remained intact above the 3800 ft level (440 ft above the detonation point).

500 1 1 1 1 1 1 O MlcrofVacrurina. • Core, drift, and tunnel observations ^ In-iifu permeability _ \7 Chimney pressurization 400 - [») i Hardhot y^r JEJ^ t Piledriver s French Granite ^7 » Salmon 8 300—h 7 Gnome 3Rc is Gasbuggy " Handcar " Rainier 7 Jr sQ\ •^"ISR 2 200 — jf c —

100 r-

r^^ 1 1 1 1 , 20 40 60 80 100 120 140 Cavity radius, R — ft Flg. 12. Observed horizontal fracture distance as a function of cavity radius for a number of nuclear detonations in various media. Included are data from explosions in granite, dolomite, tuff, salt, and shale. 14- a depth of 6000 ft s isumed that the rock since the calculations indicate some in­ above 2000 ft had no tensile strength and crease in velocity to that point. consisted, in essence, of layers resting This surface spall is an example of a on top of each other. Figure 13 shows more general phenomenon occurring when the velocity profile obtained. On this a compression wave encounters bound­ basis we expect that the top 170 ft will aries between materials of high impedance suffer a temporary separation as the (density X wave velocity) and those of stress wave strikes it and reflects from lower impedance. A series of calcula- 14 the surface. It is conceivable that the tions was undertaken to investigate spall depth might be as much as 360 ft. whether the oil-rich shales of the

3LJ_

Maximum spall f (360 ft\J) Spall depth (170 ft) J

'/ / /J SEE Oil shale 1 2000 -WMM. Lean shale T

3000--

a. 4000-i

5000-"

6000 -10 1 2 3 Particle velocity — m/see

7000

Fig. 13. Calculatec1 velocities in the rock vertically above a 100 kt explosion at a depth of 6000 ft at the Rio Blanco site. The maximum spall depth does not extend as far as the shallowest oil-bearing rock at the Rio Blanco site. -15' Depth Compressional velocity ft/sec Density g/cro in ft 8000 _ 10,000 12,000 7000 | 9000 | 11,000 I 2.1 2,2 2.,3 2,4 2,5 J_i_ I L-J I I I I I I

200

400

600-

800-

1000 •

1200-

1400 •

1600-

1800 --

2000 --

2200

2400 -+-

2600

2800 Fawn Geek ^3 Ryan '2 2.5 mi from ground zero 7.0 mi from ground zero

Pig. 14. In-situ density and velocity data from two wells in the vicinity of the Rio Blanco emplacement well. Discontinuity in average values occurs at a depth between 1700 and 2000 ft.

16- Parachute Creek Formation might cause flected from the discontinuity at a depth an impedance mismatch large enough to of 1966 ft were calculated for oil contents result in a subsurface separation. That up to 60 gal/ton in the upper layer; such a discontinuity exists at a depth of about a mismatch is twice as drastic as any 1900 ft can be seen from the density and observed at the Rio Blanco Bite. Again, velocity logs shown in Fig. 14. This is the rock was assumed to possess zero consistent with observations presented in tensile strength. The results of these Fig. 15, which shows that densities and calculations, which have been described 14 velocities decrease as the oil content of in detail by Terhune, show that in no the shale increases. Tests on the case could the weak tensile waves cause strengths of oil shale also yield the re­ any subsurface separation, since in all sults (see Fig. 16) that the higher the oil cases the compressive stresses due to content the weaker the rock will be. the overburden are dominant. These data are used as input quantities Surface motions similar to those ex­ to the calculational model depicted in pected from Rio Blanco were observed Fig. 17. The pressure profile of the cal­ and measured from the Gasbuggy detona­ culations mentioned above was applied at tion. Figure 18 is a map of the gas the 3376 ft level. The tension waves re­ wells and pipelines within 1 mile of the

Sonic log travel time — jisec/ft 140 120 100 60 1 USBM relationship from cores in Mahogany Zone shales in Piceance Creek and Uinta Basins B - Bardsley and Algermissen relationship from cores in Uinta Basin, Utah C - Bardsley and Algermissen sonic log relationship

1.60 1.80 2.00 2.20 2.40 2.60 3 Density — g/cm

Fig. 15. Experimentally determined decrease in density and velocity for oil shale with increasing oil content. -17- ' 1 • 1 ' i • i • i > i > i ' 6 - » Brittle-ductile point 1 —— Fractured strength Wagon Wheel shale -v ^^^^" 1 CM ;

ii 2 \- ID _.—*""""" Oil shale (18gal/ton)- - ^Oil shale (26 gal/ton) ^-""T I,I. 1,1,1,1.1. 6 8 10 12 14 16

Pm = (o, + 2

Fig. 16. Shear strength of shale as a function of pres&ure. The higher the oil content, the weaker the shale becomes.

point on the ground surface directly above 1 Groun d surface the Gasbuggy explosion. This figure also < shows the peak accelerations, velocities, Shale B and displacments measured at these dis­ v e sourc ac e — f t tances. Except for the well at 43 5 ft, o s 4 4 c c which was fully stemmed prior to the E detonation, gas has been produced from Shale A all the other wells shown. No subsurface

Dept h or surface damage has been observed in inc e fro m ex p inc e fro m ex p any of the wells, surface equipment, or 337_ 6 * "~ |A,>plie d pressure profile) 1 fi

Compressional connecting piplines. It was indeed dif­ Density veloc:ty ficult to detect any surface damage what­ Shale type (km/sec) Impedance (g/«5 soever; an example is shown in Fig. 19, A (Wagon Wheel) 2.A5 4.12 10.1 which is a photograph of the wellhead of Bl (Oil shale, 2.19 2.79 6.12 25 pal/ton) the emplacment hole for the Gasbuggy B2 (OM shale, 2.0 2.23 4.46 detonation taken a few hours after the ex­ 40 gal/ton) plosion. Postshot drilling at Gasbuggy B3 (Oil shale, 1.7 2.0 3.4 60 gal/ton) encountered no difficulties in the spall region. This is consistent with experience Fig. 17. Input constants and model for at the Nevada Test Site, where the explo­ calculations investigating the possibility of subsurface sion regions are routinely explored by separation. means of holes drilled postshot.

-18- / $—•— 7 (4000 ft) / / / / N^(435 ft) \ / yf^\ 10-30 g \ / / ( 9 ) 150-170 cm/sec / VJ^y 15-20, '

I -$-(4000 ft) I

Fig. 18. Locations of projucing gas wells and connecting pipe lines within 1 mile of Gasbuggy. Measured surface motions indi­ cated on this figure show the effect of spall; the higher value of motion occurs upon fallback of the surface layer.

Fig. 19. Gasbuggy emplacement wellhead being checked for gas tight­ ness immediately after the Gasbuggy detonation. Note that the sand filling the area around the wellhead is still intact, as is the light bulb attached near the top flange. 19- EXPLOSION-INDUCED FAULT MOTION Fault Dashed where inferred; Pre- and postshot examination of the arrow on downrhrown side. ground surface above a number of detona­ 12 tions at the Nevada Test Site has revealed that preexisting faults have undergone Explosion-produced fracture N movement as a result of the detonations. 17 Arrows show relofive horizontal movement; number is vertical High-speed photography during on3 of the displacement (in cm) and on downthrown side. events indicated that the fault motion started with the first arrival of the com- pressional wave. Most of the data treat fault displacement from explosions in the Pahute Mesa area of the Nevada Test Site; this area is characterized by a high den­ sity of faults generally in a north-south direction. Figure 20 is an example of fault- displacement observations; it shows the faults activated by the 65-kt Duryea ex­ plosion, which was detonated at a depth of approximately 1800 ft. Analysis of a number of such displacement, figures for explosions of different yields leads to the exclusion that the distance of an activa­ ted fault i3 related in a rather regular way to the yield of explosion that caused the displacement. This relation is shown Feet in Fig. 21, in which are plotted both the perpendicular distance from the emplace­ Fig. 20. Faults existing prior to the 65-fct Duryea explosion on ment hole wellhead to the farthest activa­ Pahute Mesa at NTS and mo­ ted fault and the distance from the well­ tions along these faults caused by the detonation. Both hori­ head to the point of the farthest fault zontal and vertical displace­ motion. ments were observed. On the basis of these data, we expect the Rio Blanco Project is not known, and no motion on a preexisting fault closer no data are available for detonations in than about 6000 ft (2000 m) from a 100 kt the sandstone/shale sequences of the explosion. It must be remembered that Piceance Creek Basin. No fault motion these data were derived from relatively was detected as a consequence of either shallow detonations—the depths were be­ the Gasbuggy or the Rulison detonations, tween about 1800 and 4000 ft. To what although a number of faults were postu­ extent this picture might be modified for lated to be within 750 ft of the Gasbuggy deeper explosions such as are planned for detonation. -20- 2 -i 1—i—r—r- T—i—riii i \p o ® 104 -it 7 II 1/ n t 2 oo o Perpendicular I 4 A S *•* distance to farthest activated I Fault a Distance to point of farthest fault motion'

itr j^J 1 1 1—l„J-,L.iJ- L±- _I—i—i—• • < • 10 100 1,000 10,000 Yield — h

Pig. 21. Relationship between the distance from surface zero to activated faults and the yield for detonations of various yields on Pahute Mesa.

Fig. 22. Known surface and inferred subsurface faults within the Rio Blanco Unit. The closest subsurface fault indication is about 2 miles from Rio Blanco, while the closest surface fault Is about 3j miles away.

-21- Figure 22 shows the faults known to be 10 ~i i i J i nil "T I I I l l III present in the Rio Blanco Unit. Included —~ Mean 18 are faults exposed at the surface as ±1

EFFECTS ON MINES the Fawn Creek site, and its closest ap­ proach to the Rio Blanco unit boundary For potential damage to mines as well is about 8 miles. The peak acceleration as to surface installations to be predicted, at the TOSCO mine from the Rio Blanco ground motion must be reliably predicted. detonation is expected to be approximately Although this always involves some un­ 0.06 g. The peak acceleration measured certainty for a new area, the data from at the TOSCO mine from the Rulison deto- 20 Ruli8on and Gasbuggy together with theo­ nation was between 0.05 and 0.1 g, which retical work give a large measure of caused no damage. Therefore, we expect confidence to the Rio Blanco predictions. no damage from the Rio Blanco detonation. The expected peak acceleration as a The next closest mine to Rio Blanco is 19 function of distance is shown in Fig. 23. about 32 miles to the northwest, on the The TOSCO oil shale mine on Parachute White River; Fig. 24 shows the locations Creek is the closest existing mine to the of all existing mines within 55 miles of Rio Blanco detonation and to the Rio the Rio Blanco site. Many of these mines Blanco Unit. It is about 18 miles from were investigated for damage following

-22. 0 Active mines • Inactive mines

tone J V

o'l 10 20 30 Cisco

Fie. 24. Locations of active and inactive mines and quarries within about 60 miles of the Rio Blanco site.

21 the Rulison detonation. Only in one summarizes the result of the Rolison mine, the Cameo Coal Mine, located mine investigation. 27 miles from the Rulison explosion, was Information pertinent to the question of any damage detected. This occurred in mine damage has alsobeen obtained from the shallow cover near an outcrop where some of the nuclear explosions attheNevada the roof conditions were generally poor. Test Site that have taken place in various By contrast, the Mobil and the Bureau of tunnels dug in the tuff of Rainier Mesa. Mines oil shale mines, located 9 and Table 2 lists the farthest scaled distances 10 miles, respectively, from Rulison, at which damage was observed in the tun­ sustained no damage whatsoever—in fact, nels. In almost all cases this first indica­ the very extensive and sensitive meas­ tion of damage was extremely minor and urements in the USBM mine did not detect generally occurred in a weak geologic area. any roof sag, pillar displacement, or Based on these observations, one would 22 other permanent effects. Table 1, expsct tunnel damage out to about 6000 <"' based on the Bureau of Mines report. from a 100 let explosion.

•ii* Table 1. Effects of the Rulison Event on mines in the vicinity. Peak Distance acceleration (miles) Mine Mine features (g) Damage/comments

9 Mobil oil shale 0.06 No damage to mine; 10 USBM oil shale Room and pillar 0.06 aome rock falls on • canyon walls and Union oil shale (roof poor to 15 good) along access roads 17 Colony oil shale 0.05-0.1 20 Nu-Gap coal Truck mine -0.03 No damage 23 Rifle vanadium Room and pillar -0.03 No damage 27 Cameo coal Room and pillar -0.04 Small roof fall; cracked caprock 27 Roadside coal Room and pillar -0.04 Toppled timber prop 29 Coal Canyon Auger mine — No damage 32 Red Canyon coal -0.007 No damage 32 Green Valley coal -0,007 No damage 33 Top coal Small truck mine -0.007 No damage 34 McGinley coal (generally in No damage pitching seams) 34 Four-Mile coal -0.005 No damage 35 Dutch Creek coal — No damage

Table 2. Farthest distances at which damage to tunn els was observed at Nevada Test Site.23 D istance to fi rst visible Damage in lamage in other tunnels ei nplacement Distance Event Location tut inel (ft/kt1/3) Loca tion (ft/ktiyS) Remarks Midi Mist U12N-02 480 U12* -03 1300 Considerable damage in weak clay zone of U12N-03 Hudson Seal U12N-04 500 — — — Diana Mist U12N-06 680 — — Minor bulging of sets Dorsal Fin U12E-10 410 — — — Diesel Train U12E-11 430 U12E -10 1250 Loose slabs in weak clay zone Hudson Moon U12E-12 770 — — — Door Mist U?2G-07 670 — — Extensive heaving Cypress U12G-09 380 — — — Double Play U16A-03 430 — — — Ming Vase U16A-04 410 — — Minor shift of tracks

•24- Summary

This paper has examined a number of 4) No movement on any fault is ex­ potentially harmful effects of proposed pected to result from Rio Blanco. How­ nuclear detonations in the Fort Union- ever, observations at NTS indicate that Mesaverde Formation in a portion of the some fault motion might be triggered from Piceance Basin on the overlying oil shale subsequent detonations in the unit. It and mineral deposits. The results can would therefore seem prudent to exercise be summarized as follows: caution in choosing the location of future 1) All detonations will be 2300 ft or detonations and examine faults for any more below any of the oil- or mineral- explosion-induced movement. It should be containing strata. Since fracturing (even recognized that there is no evidence that on a microscopic scale) is not expected to fault motion, should it occur, would be in extend for more than 400 ft from the ex­ any way harmful. plosives, no fracturing into the formation 5) No damage to any existing mine is containing oil shale and other minerals expected from the Rio Blanco explosion. will occur. The TOSCO mine, closest to the explosion 2) The depth of surface spall from a center, should experience the same levsl 100 kt explosion at a depth of 6000 ft, even of ground motion it did from th« Huiison neglecting rock tensile strengths, is ex­ explosion, which caused no damage. The pected to be 170 ft, but might possibly be TOSCO facility will also be closer than as much as 360 ft. Except in the extreme any other mine to the subsequent proposed southwest corner of the unit, this spall explosions, since it approaches to within depth would therefore not extend down into about 8 miles of the boundary of the eastern the richer oil shales. part of the unit. However, from the re­ 3 * No subsurface separation will occur sponse of the Mobil and USBM mines from as a result of tension waves reflected from Rulison we expect no damage, although a discontinuities between oil-rich and oil- reexamination should be made after the lean layers. Phase-2 explosions.

Acknowledgments

Among those who have helped the Mines), Wendell Weart (Sandia Labora­ authors in the preparation of this paper, tories, Albuquerque), and Charles Gary H. Higgins and Robert W. Terhune Boardman, Carrol Knutson, and Ed Alcock (LLL), Paul Russell (U. S. Bureau of (CER-Geonuclear) deserve special thanks.

-25- References

1. Project Rio Blanco Demonstration Plan, CER-Geonuclear Corp., Las Vegas, Nevada, 1971. 2. Minutes of the October 19. 1971, Meeting of the Governor's Special Advisory Com­ mittee or. the Rio Blanco Nuclear Stimulation Project. State of Colorado, Denver, Colorado, 1971. 3. Project Rio Blanco: Geology of the Piceance Basin, CER-Geonuclear Corp., Las Vegas, Nevada, 1971. 4. K. W. Stanfield et al., Oil Yields of Sections of the Green River Oil Shale in Colorado, 1957-1963, U. S. Bureau of Mines, Washington, D. C., Rept.RI-7051 (1967). 5. J. W. Smith and N. B. Young, Determination of Dawsontte and Nahcoltte in Green River Formation Oil Shales, U. S. Bureau of Mines, Washington, D. C, Rept. 7286 (1969) 6. S. W. West, U. S. Geological Survey, Denver, Colorado, private communication, 1971. 7. Project Rio Blanco Definition Plan, CER-Geonuclear Corp., Las Vegas, Nevada, 1971. Vol. L 8. i. Y. Borg, Observed Fracture Radii Around Underground Shots. Lawrence Livermore Laboratory, Internal Rept. SDK-71-3 (1971). 9. A. Holzer, Gaabuggy in Perapectlve, Lawrence Livermore Laboratory, Rept. UCRL-72175 (1970). 10. M. Reynolds, Jr., Trans. Amer. Nucl. Soc. 14, 687 (1971). 11. R. W. Terhune, Predictions of Explosion Effects in Wagon Wheel Sandstone. Lawrence Livermore Laboratory, Rept. UCRL-50993 (1971). 12. J. T. Cherry et al.. Int. J. Rock. Mech. 5, 455 (1968). 13. J. D. Eisler and F. Chilton, J. Geophys. Res. 69, 5285 (1964). 14. R. W. Terhune, Prediction of Spall Phenomena and Near Surface Effects for Project Rio Blanco. Lawrence Livermore Laboratory, Rept. UCID-15922 (1971). 15. W. R. Perret, Gasbuggy Seismic Source and Surface Motion. U.S. Army Engineer Explosive Excavation Research Office. Livermore, California. Kept. PNE-1002 (1969). 16. P. C. Ward, Safety Survey of Gas Wells and Associated Facilities in the Project Gasbuggy Area. U. S. Army Engineer Explosive Excavation Research Office, Livermore, California, Rept. PNE-1011 (1969). 17. F. A. McKeownandD. D. Dickey, Bull. Selsmol. Soc. Amer. j>9. 2253 (1969). 18. J. R. Donnell, Tertiary Geology and Oil Shale Resources at the Piceance Creek Basin Between the Colorado and White Rivers, Northwest Colorado. V. S. Geological Survey, Washington, D.C.. Bull. 1082-L (1961). 19. Predictions of Ground Motion. Rio Blanco Event. Environmental Research Corp.. Las Vegas, Nevada, Rept. NVO-1163-228 (1971).

-26- 20. W. W. Haya, Environmental Research Corp., Las Vegas, Nevada, private com­ munication, 1971. 21. R. L. Bolmer, Mine Effects Evaluation tor Project Rultaon, U. S. Bureau of Mines, Washington, D.C... Rept. USBM-1002 (1970). 22. P. L. Russell, Dynamic and Static Response of the Government Oil Shale Mine at Rifle. Colorado, to the Rultaon Event, U. S. Bureau of Mines, Washington, D. C, Rept. OSBM-1001 (1970). 23. W. Weart, Sandia Laboratories, Albuquerque, New Mexico, private communication, 1971.

-27- ^ - - - ,

SA. available fro.n the N« .ormi i .•;! ton Cttnter, National Bureau of Sta.iuar *nt of Commerce, Springfield, \ s gini; Printed Copy $ft.OO; Mjcfoficn* S' .&S.