CA1138212A - Method of sealing salina excavations - Google Patents
Method of sealing salina excavationsInfo
- Publication number
- CA1138212A CA1138212A CA000340032A CA340032A CA1138212A CA 1138212 A CA1138212 A CA 1138212A CA 000340032 A CA000340032 A CA 000340032A CA 340032 A CA340032 A CA 340032A CA 1138212 A CA1138212 A CA 1138212A
- Authority
- CA
- Canada
- Prior art keywords
- salt
- isostructural
- salting out
- solution
- rock mass
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 29
- 238000007789 sealing Methods 0.000 title claims abstract description 26
- 238000009412 basement excavation Methods 0.000 title claims abstract description 13
- 241001466077 Salina Species 0.000 title 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 60
- 238000005185 salting out Methods 0.000 claims abstract description 40
- 150000003839 salts Chemical class 0.000 claims abstract description 39
- 239000011435 rock Substances 0.000 claims abstract description 38
- 239000011780 sodium chloride Substances 0.000 claims abstract description 38
- 239000003960 organic solvent Substances 0.000 claims abstract description 10
- 235000002639 sodium chloride Nutrition 0.000 claims description 71
- 239000000243 solution Substances 0.000 claims description 34
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M potassium chloride Inorganic materials [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims description 28
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 27
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 21
- 239000012266 salt solution Substances 0.000 claims description 16
- 239000013078 crystal Substances 0.000 claims description 15
- 239000001103 potassium chloride Substances 0.000 claims description 14
- 235000011164 potassium chloride Nutrition 0.000 claims description 14
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 13
- 239000001110 calcium chloride Substances 0.000 claims description 11
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 11
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 10
- 150000001450 anions Chemical class 0.000 claims description 6
- 239000007864 aqueous solution Substances 0.000 claims description 6
- 150000001768 cations Chemical class 0.000 claims description 6
- 239000013049 sediment Substances 0.000 claims description 5
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 3
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 claims description 3
- 239000002244 precipitate Substances 0.000 claims description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical group [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims 1
- 150000002500 ions Chemical class 0.000 claims 1
- 239000007788 liquid Substances 0.000 abstract description 2
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 13
- 235000011147 magnesium chloride Nutrition 0.000 description 13
- 235000011148 calcium chloride Nutrition 0.000 description 11
- 238000002425 crystallisation Methods 0.000 description 11
- 230000008025 crystallization Effects 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 208000012868 Overgrowth Diseases 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000000725 suspension Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 3
- 235000019341 magnesium sulphate Nutrition 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 230000002269 spontaneous effect Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- PALNZFJYSCMLBK-UHFFFAOYSA-K magnesium;potassium;trichloride;hexahydrate Chemical compound O.O.O.O.O.O.[Mg+2].[Cl-].[Cl-].[Cl-].[K+] PALNZFJYSCMLBK-UHFFFAOYSA-K 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000001175 calcium sulphate Substances 0.000 description 1
- 235000011132 calcium sulphate Nutrition 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 239000001120 potassium sulphate Substances 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 239000012047 saturated solution Substances 0.000 description 1
- 239000003566 sealing material Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Landscapes
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
ABSTRACT
The present invention relates to a method of sealing saline excava-tions to close capillary rifts and eliminate undesired liquid inflows which may otherwise cause flooding of the excavation. The method comprises adding to effluent a salt or organic solvent to form a salting out method which is supersaturated with regard to a salt in the salting out medium so that the supersaturated salt crystallizes in the rift wherein the supersaturated salt is the same as or is structural with the salt of the rock mass.
The present invention relates to a method of sealing saline excava-tions to close capillary rifts and eliminate undesired liquid inflows which may otherwise cause flooding of the excavation. The method comprises adding to effluent a salt or organic solvent to form a salting out method which is supersaturated with regard to a salt in the salting out medium so that the supersaturated salt crystallizes in the rift wherein the supersaturated salt is the same as or is structural with the salt of the rock mass.
Description
~13BZlZ
The pres~nt invention relates to a method of sealing saline excava-tions, which contain capillary rifts or cracks in the rock mass o~ the excava-tion site. By sealing such rifts or cracks, undesirable liquid inflows of effluent (underground water appearing in or beside a deposit), which may cause flooding of the excavation, can be eliminated.
A known method of sealing capillary rifts in a rock mass comprises warming the rock mass by first introdùcing dilute carnallite (KCl MgC12 H20~
liquor, at a temperature lower than 363K (Kelvin's degrees) but higher than the rock mass temperature, to holes drilled in the rock mass in the vicinity of the cracks or rifts. Supersaturated carnallite liquor, having a temperature of from 363 to 423~K is then introduced under pressure to the warmed rock mass.
A disadvantage of this method is that sylvine ~KCl) crystals, which are pre-cipitated during crystallization do not satisfactorily seal the rifts because of the spontaneous crystallization caused by the extreme temperature gradient.
Therefore the present invention seeks to find a sealing method which does not rely upon sharp temperature gradients to achieve crystal growth in the cracks and thereby can effect a more controlled or uniform sealing of the cracks.
According to the present invention there is provided a method of sealing cracks or capillary rifts in the rock mass of saline excavations com-prising supplying to the crack or rift a substantially saturated solution of a salt isostructural with the salt forming the rock mass and at the same time or subsequently adding a salting out medium which causes the isostructuTal salt to crystallize on the surfaces of the walls of the cracks OT rifts thereby sealing the cracks OT rifts, wherein the salting out medium is an aqueous solution of a salting out salt or an organic solvent, and the temperature of the isostructuTal salt solution and the salting out medium is substantially '~
~138;~
the same as the temperature of the rock mass.
The term saline excavation is intended to include excavations of a rock salt or potassium salt mine.
In general the effluent contains isostructural salt and according to the invention the salting out medium is added to this effluent. If the effluent contains insufficient isostructural salt it may be modified by en-riching it to the required concentration of isostructural salt. Alternatively, a solution of required concentration of isostructural salt may be made independ-ently and used in place of the effluent or modified efluent. The term isostructural salt as used herein refers to a salt which is identieal to or isostructural with the salts forming rock mass. Therefore the term isostruc-tural salt solution as used herein is intended to include unmodified effluent which contains sufficient isostructural salt, modified effluent which has been modified by enrichment in an isostructural salt, and a solution prepared independently of the effluent by dissolving sufficient isostructural salt in water.
According to the invention a salting out medium comprises an aqueous solution of a salting out salt, which may be called the salting out solution, or an organic solvent. The salting out medium is selected so as to disturb the saturation of the effluent or modified effluent so that the iso-structural salt will crystallize on the surfaces of the cracks in the rock mass.
The amount of added salting out medium, which modifies the composition of the effluent, should be such as to stimulate initial crystallization on the walls of the rifts. To increase the~ëffect of crystallization it is advantageous to form crystal nuclei of the native rock mass or foreign salts in the suspen-sion, especially those of calcium sulphate, calcium carbonate or magnesium carbonate, In the subsequent phase of the sealing process crystal nuclei are overgrown with crystals isostructural with the rock mass.
C
11382~2 A preferred salting out medium is a solution of a water soluble salt or salts, especially calcium chloride or magnesium chloride. They cause salting out of, for example, sodium chloride or potassium chloride which crystallize on the rims of the rift walls. If sulphates and carbonates are present in the effluent there occurs simultaneously crystallization of spar-ingly soluble respective calcium and magnesium salts.
Another salting out medium which can be usedin this invention comprises organic solvents. As the organic solvents methanol or acetone are applied advantageously. They first cause crystallization of sulphates, then almost simultaneously, crystallization of sodium chloride and potassium chloride.
Calcium and magnesium chlorides remain in the liquor. The salting out medium is introduced under pressure into the rift at least a few meters away from the outlet of the effluent, through an appropriately drilled hole.
By the method according to the invention of sealing saline excava-tions which possesscapillary rifts the isostructural salt solution, which may be effluent, modified effluent or a solution prepared independently to the required degree of saturation, may be continuously introduced with a salting out solution, under pressure. Good sealing results are also achieved by intro-ducing isostructural salt solution and salting out solution alternately, or further the isostructural salt solution may be supplied whilst a salting out solution is added batchwise. Alternating the supply of isostructural salt solution with salting out solution results in the crystals overgrowth on the walls of the capillary rifts.
When the application of the above methods doesn't completely seal the rock mass, the isostructural salt solution may be introduced followed by the salting out solution, with the difference that the isostructural salt solution contains cations or anions, and the salting out solution anions or cations which form a precipitate of crystals of a sparingly soluble salt which .~
113BZlZ
is not isostructural with the rock mass salt. This sediment thus mechanically seals the capillary rifts and cracks. In this latter method, the solutions used are simultaneously oversaturated towards e.g. sodium chloride and they form a ~irm bond of the one sediment crystals with another and with the walls of the rift.
Inorganic salts, readily water - soluble, advantageously calcium chloride or magnesium chloride alternatively organic solvents such as methanol or acetone are applied as salting out media. Methanol or acetone cause crystallization of sulphates first and then almost simultaneously sodium chloride and potassium chloride. Where modification of effluent is required, it may be achieved advantageously at a temperature higher than the rock mass temperature, adjusting to obtain the required degree of oversaturation, which will effect overgrowth of crystals on the walls of the capillary rifts but yet will avoid spontaneous formation of crystal nuclei.
The inductive period should hence last up to several hours, depending on the length and size of the rifts or cracks and the intensity of the rate of flow of the sealing solution through them.
In the last stage of sealing it is recommended to prepare the isostruc~ural salt solution to such a degree of oversaturation which will also effect spontaneous crystal nuclei formation in the suspension.
The virtue of the method according to the invention is a substan-tial reduction in the formation of gaps in the contact area between the sealing material and the rock mass. Application of the rock mass salts and also salts isostructural with them permits improved reliability of sealing.
The method according to the invention is illustrated by the following examples, which are not intended to exclude their wider range of application. The linear speeds of crystallization were achieved at a constant flow rate of modified effluent, of 1.7 x 10 3 m/s.
.C
~138~1Z
le I:
To 128 kg of effluent containing 2.4 kg of sodium chloride, 1.8 kg potassillm chlorlde, 8.9 kg magnesium sulphate, 24.4 kg magnesium chloride, 83 kE~ of methanol were introduced into a hole drilled in a rock mass sample.
Potassium sulphate and magnesium sulphate crystallized in the sediment and sodium chloride partially with potassium chloride crystallized on the walls of the rift and paTtially in the sediment. The linear speed of the rift walls overgrowth amounted to 4.5 x 10 9 m/s.
Example II:
To 123 kg of effluent containing 14.6 kg of sodium chloride, 1.7 kg potassium chloride, 7.6 kg magnesium chloride and 9.2 kg calcium chloride 15 kg of methanol were introduced into a drilled hole in a mass rock sample. Sodium chlorids crystallized on the wall of the rift with linear speed of 9.3 x 10 9 m/s, Example III:
To 123 kg of effluent of the same composition as in the example II, 4 kg of calcium chloride solution of concentration 41.4% were introduced.
Crystallization of sodium chloride occurred on the walls of the rift with the linear speed of 7.2 x 10 9 m/s.
-4a-.C
11~8~1Z
Example IV:
To 127 kg of effluent containing 1.5 kg of sodium chloride, 1.7 kg potassium chloride and 34.skg magnesium chloride 20 kg of calcium chloride soluti,on of concentrati,on 44% were introduced into a drilled hole in a rock mass sample. The linear speed of sodium chloride crystallization together wtih potassium chloride amounted to 6.7 x 10 9 m/s.
Example V:
To 128 kg of efn uent of the same composition as in example I, 53 kg of magnesium chloride solution were introduced~ Sodium chloride crystallized together with potassium chloride with the linear speed of 9.3 x 10,9 m/s.
Example VI:
To 123 kg of effluent of composition similar to that of example III, 13.4 kg of 35% magnesium chloride solution were introduced. Sodium chloride crystallized with the linear speed of 1.1 x 10 8 m/s.
Example VII:
To a bore-hole drilled in a zone of capillary rifting in a rock salt bed of temperature 293 K, sealing solution was introduced under pressure of 1.52 x 105Pa, by portions. The batches of the solution were prepared from brine obtained by dissolving of 1.23 kg of sodium chloride and 27.19 kg of magnesium chloride in 70.24 kg of water and mixed before introducing to the bore-hole with equal amount of 44.45% aqueous solution of calcium chloride in order to obtain a solution saturated with regard to sodium chloride at tempera-ture 308K. After flowing by portions .3m3 of such prepared solution through the sealed rock mass its flow rate decreased to 18.7% of the starting value.
Example VIII:
To a bore-hole drilled in a rock mass as in example VII, a sealing solution ~as introduced by portions under pressure of 2 x 105Pa. The batches of solutions~wero; prepared from the saline obtained by dissolving 11.87 kg of ;21Z
sodium chloride, 1.34 kg potassium chloride, 6.18 kg magnesium chloride and 7.52 kg of calcium chloride in 73.09 kg of water and mixed before introducing to the bore-hole with equal amount of 49% aqueous calcium chloride solution to obtain the solution saturated with regard to sodium chloride at temperature 308 K. After .7m3 of the solution had passed in portions through the sealed rock mass its flow rate decreased to 6% of the starting value. In order to achieve complete sealing of the rock mass sealing solution containing 1.85 kg of sodium chloride, 1.44 kg of potassium chloride, 6.96 kg magnesium sulphate and 19.09 kg of magnesium chloride dissolved in 70.66 kg of water, followed with the solution containing 5% calcium chloride solution and 21.7% of sodium chloride, saturated with regard to sodium chloride at temperature 303K, were introduced under pressure 2 x 105Pa, alternately by portions. After two cycles of alternate introducing of these solutions to the rock mass, complete sealing of the rock mass was achieved.
Example IX:
To the bore-hole drilled in a rock mass like in the example VII, to the efluent of the composition: 11.87 kg of sodium chloride, 1.39 kg potassium chloride, 6.18 kg magnesium chloride and 7.52 kg calcium chloride dissolved in 73.14 kg of water, forced under pressure of 3.03 x 105Pa, 49% aqueous solution of calcium chloride was introduced by portioning. After allowing the efn uent and 49% solution of calcium chloride to flow with the volume rate 50:1 and total volume of .4m3, the effluent flow rate decreased to 5% of the starting value.
The method, according to the invention finds wide application espe-cially in rock salt and potassium salt ~ines.
1138~1%
The subject of the invention is the method of sealing saline excavations based on that to effluent, into the rift of the mass rock, salt-ing out substances are introduced in form of inorganic salts or organic solvents in quantity and quality adjusted to the properties of the effluent, determined by its complete chemical analysis and solubility isotherm of a proper system, selecting such dcgree of oversaturation which secure maximum linear speed of the rift walls overgrowth by crystals identical and/or isostructural to the rock mass forming salts. Additionally also advantageous is forming of crystal nuclei of the rock mass salt or foreign in the sus-pension what accelerate the sealing process.
The method is characterized by that, the salting out substances are calcium chloride or magnesium chloride and like organic solvents methanol or acetone is applied.
The point of the method is that the efluent and/or modified saline previously modified with salting out solutions are introduced continuously under pressure or alternately the effluent and/or the saline and salting out solutions or continuously the effluent and/or the saline and by portioning salting out solutions or alternately the effluent and~or the saline followed by salting out solutions, with that the effluent and/or the saline contains cations or anions whereas the salting out solutions contain anions or cations which in the effect of the reaction form rifts sealing suspensions of crystals identical and/or isostructural with the rock mass salts.
The pres~nt invention relates to a method of sealing saline excava-tions, which contain capillary rifts or cracks in the rock mass o~ the excava-tion site. By sealing such rifts or cracks, undesirable liquid inflows of effluent (underground water appearing in or beside a deposit), which may cause flooding of the excavation, can be eliminated.
A known method of sealing capillary rifts in a rock mass comprises warming the rock mass by first introdùcing dilute carnallite (KCl MgC12 H20~
liquor, at a temperature lower than 363K (Kelvin's degrees) but higher than the rock mass temperature, to holes drilled in the rock mass in the vicinity of the cracks or rifts. Supersaturated carnallite liquor, having a temperature of from 363 to 423~K is then introduced under pressure to the warmed rock mass.
A disadvantage of this method is that sylvine ~KCl) crystals, which are pre-cipitated during crystallization do not satisfactorily seal the rifts because of the spontaneous crystallization caused by the extreme temperature gradient.
Therefore the present invention seeks to find a sealing method which does not rely upon sharp temperature gradients to achieve crystal growth in the cracks and thereby can effect a more controlled or uniform sealing of the cracks.
According to the present invention there is provided a method of sealing cracks or capillary rifts in the rock mass of saline excavations com-prising supplying to the crack or rift a substantially saturated solution of a salt isostructural with the salt forming the rock mass and at the same time or subsequently adding a salting out medium which causes the isostructuTal salt to crystallize on the surfaces of the walls of the cracks OT rifts thereby sealing the cracks OT rifts, wherein the salting out medium is an aqueous solution of a salting out salt or an organic solvent, and the temperature of the isostructuTal salt solution and the salting out medium is substantially '~
~138;~
the same as the temperature of the rock mass.
The term saline excavation is intended to include excavations of a rock salt or potassium salt mine.
In general the effluent contains isostructural salt and according to the invention the salting out medium is added to this effluent. If the effluent contains insufficient isostructural salt it may be modified by en-riching it to the required concentration of isostructural salt. Alternatively, a solution of required concentration of isostructural salt may be made independ-ently and used in place of the effluent or modified efluent. The term isostructural salt as used herein refers to a salt which is identieal to or isostructural with the salts forming rock mass. Therefore the term isostruc-tural salt solution as used herein is intended to include unmodified effluent which contains sufficient isostructural salt, modified effluent which has been modified by enrichment in an isostructural salt, and a solution prepared independently of the effluent by dissolving sufficient isostructural salt in water.
According to the invention a salting out medium comprises an aqueous solution of a salting out salt, which may be called the salting out solution, or an organic solvent. The salting out medium is selected so as to disturb the saturation of the effluent or modified effluent so that the iso-structural salt will crystallize on the surfaces of the cracks in the rock mass.
The amount of added salting out medium, which modifies the composition of the effluent, should be such as to stimulate initial crystallization on the walls of the rifts. To increase the~ëffect of crystallization it is advantageous to form crystal nuclei of the native rock mass or foreign salts in the suspen-sion, especially those of calcium sulphate, calcium carbonate or magnesium carbonate, In the subsequent phase of the sealing process crystal nuclei are overgrown with crystals isostructural with the rock mass.
C
11382~2 A preferred salting out medium is a solution of a water soluble salt or salts, especially calcium chloride or magnesium chloride. They cause salting out of, for example, sodium chloride or potassium chloride which crystallize on the rims of the rift walls. If sulphates and carbonates are present in the effluent there occurs simultaneously crystallization of spar-ingly soluble respective calcium and magnesium salts.
Another salting out medium which can be usedin this invention comprises organic solvents. As the organic solvents methanol or acetone are applied advantageously. They first cause crystallization of sulphates, then almost simultaneously, crystallization of sodium chloride and potassium chloride.
Calcium and magnesium chlorides remain in the liquor. The salting out medium is introduced under pressure into the rift at least a few meters away from the outlet of the effluent, through an appropriately drilled hole.
By the method according to the invention of sealing saline excava-tions which possesscapillary rifts the isostructural salt solution, which may be effluent, modified effluent or a solution prepared independently to the required degree of saturation, may be continuously introduced with a salting out solution, under pressure. Good sealing results are also achieved by intro-ducing isostructural salt solution and salting out solution alternately, or further the isostructural salt solution may be supplied whilst a salting out solution is added batchwise. Alternating the supply of isostructural salt solution with salting out solution results in the crystals overgrowth on the walls of the capillary rifts.
When the application of the above methods doesn't completely seal the rock mass, the isostructural salt solution may be introduced followed by the salting out solution, with the difference that the isostructural salt solution contains cations or anions, and the salting out solution anions or cations which form a precipitate of crystals of a sparingly soluble salt which .~
113BZlZ
is not isostructural with the rock mass salt. This sediment thus mechanically seals the capillary rifts and cracks. In this latter method, the solutions used are simultaneously oversaturated towards e.g. sodium chloride and they form a ~irm bond of the one sediment crystals with another and with the walls of the rift.
Inorganic salts, readily water - soluble, advantageously calcium chloride or magnesium chloride alternatively organic solvents such as methanol or acetone are applied as salting out media. Methanol or acetone cause crystallization of sulphates first and then almost simultaneously sodium chloride and potassium chloride. Where modification of effluent is required, it may be achieved advantageously at a temperature higher than the rock mass temperature, adjusting to obtain the required degree of oversaturation, which will effect overgrowth of crystals on the walls of the capillary rifts but yet will avoid spontaneous formation of crystal nuclei.
The inductive period should hence last up to several hours, depending on the length and size of the rifts or cracks and the intensity of the rate of flow of the sealing solution through them.
In the last stage of sealing it is recommended to prepare the isostruc~ural salt solution to such a degree of oversaturation which will also effect spontaneous crystal nuclei formation in the suspension.
The virtue of the method according to the invention is a substan-tial reduction in the formation of gaps in the contact area between the sealing material and the rock mass. Application of the rock mass salts and also salts isostructural with them permits improved reliability of sealing.
The method according to the invention is illustrated by the following examples, which are not intended to exclude their wider range of application. The linear speeds of crystallization were achieved at a constant flow rate of modified effluent, of 1.7 x 10 3 m/s.
.C
~138~1Z
le I:
To 128 kg of effluent containing 2.4 kg of sodium chloride, 1.8 kg potassillm chlorlde, 8.9 kg magnesium sulphate, 24.4 kg magnesium chloride, 83 kE~ of methanol were introduced into a hole drilled in a rock mass sample.
Potassium sulphate and magnesium sulphate crystallized in the sediment and sodium chloride partially with potassium chloride crystallized on the walls of the rift and paTtially in the sediment. The linear speed of the rift walls overgrowth amounted to 4.5 x 10 9 m/s.
Example II:
To 123 kg of effluent containing 14.6 kg of sodium chloride, 1.7 kg potassium chloride, 7.6 kg magnesium chloride and 9.2 kg calcium chloride 15 kg of methanol were introduced into a drilled hole in a mass rock sample. Sodium chlorids crystallized on the wall of the rift with linear speed of 9.3 x 10 9 m/s, Example III:
To 123 kg of effluent of the same composition as in the example II, 4 kg of calcium chloride solution of concentration 41.4% were introduced.
Crystallization of sodium chloride occurred on the walls of the rift with the linear speed of 7.2 x 10 9 m/s.
-4a-.C
11~8~1Z
Example IV:
To 127 kg of effluent containing 1.5 kg of sodium chloride, 1.7 kg potassium chloride and 34.skg magnesium chloride 20 kg of calcium chloride soluti,on of concentrati,on 44% were introduced into a drilled hole in a rock mass sample. The linear speed of sodium chloride crystallization together wtih potassium chloride amounted to 6.7 x 10 9 m/s.
Example V:
To 128 kg of efn uent of the same composition as in example I, 53 kg of magnesium chloride solution were introduced~ Sodium chloride crystallized together with potassium chloride with the linear speed of 9.3 x 10,9 m/s.
Example VI:
To 123 kg of effluent of composition similar to that of example III, 13.4 kg of 35% magnesium chloride solution were introduced. Sodium chloride crystallized with the linear speed of 1.1 x 10 8 m/s.
Example VII:
To a bore-hole drilled in a zone of capillary rifting in a rock salt bed of temperature 293 K, sealing solution was introduced under pressure of 1.52 x 105Pa, by portions. The batches of the solution were prepared from brine obtained by dissolving of 1.23 kg of sodium chloride and 27.19 kg of magnesium chloride in 70.24 kg of water and mixed before introducing to the bore-hole with equal amount of 44.45% aqueous solution of calcium chloride in order to obtain a solution saturated with regard to sodium chloride at tempera-ture 308K. After flowing by portions .3m3 of such prepared solution through the sealed rock mass its flow rate decreased to 18.7% of the starting value.
Example VIII:
To a bore-hole drilled in a rock mass as in example VII, a sealing solution ~as introduced by portions under pressure of 2 x 105Pa. The batches of solutions~wero; prepared from the saline obtained by dissolving 11.87 kg of ;21Z
sodium chloride, 1.34 kg potassium chloride, 6.18 kg magnesium chloride and 7.52 kg of calcium chloride in 73.09 kg of water and mixed before introducing to the bore-hole with equal amount of 49% aqueous calcium chloride solution to obtain the solution saturated with regard to sodium chloride at temperature 308 K. After .7m3 of the solution had passed in portions through the sealed rock mass its flow rate decreased to 6% of the starting value. In order to achieve complete sealing of the rock mass sealing solution containing 1.85 kg of sodium chloride, 1.44 kg of potassium chloride, 6.96 kg magnesium sulphate and 19.09 kg of magnesium chloride dissolved in 70.66 kg of water, followed with the solution containing 5% calcium chloride solution and 21.7% of sodium chloride, saturated with regard to sodium chloride at temperature 303K, were introduced under pressure 2 x 105Pa, alternately by portions. After two cycles of alternate introducing of these solutions to the rock mass, complete sealing of the rock mass was achieved.
Example IX:
To the bore-hole drilled in a rock mass like in the example VII, to the efluent of the composition: 11.87 kg of sodium chloride, 1.39 kg potassium chloride, 6.18 kg magnesium chloride and 7.52 kg calcium chloride dissolved in 73.14 kg of water, forced under pressure of 3.03 x 105Pa, 49% aqueous solution of calcium chloride was introduced by portioning. After allowing the efn uent and 49% solution of calcium chloride to flow with the volume rate 50:1 and total volume of .4m3, the effluent flow rate decreased to 5% of the starting value.
The method, according to the invention finds wide application espe-cially in rock salt and potassium salt ~ines.
1138~1%
The subject of the invention is the method of sealing saline excavations based on that to effluent, into the rift of the mass rock, salt-ing out substances are introduced in form of inorganic salts or organic solvents in quantity and quality adjusted to the properties of the effluent, determined by its complete chemical analysis and solubility isotherm of a proper system, selecting such dcgree of oversaturation which secure maximum linear speed of the rift walls overgrowth by crystals identical and/or isostructural to the rock mass forming salts. Additionally also advantageous is forming of crystal nuclei of the rock mass salt or foreign in the sus-pension what accelerate the sealing process.
The method is characterized by that, the salting out substances are calcium chloride or magnesium chloride and like organic solvents methanol or acetone is applied.
The point of the method is that the efluent and/or modified saline previously modified with salting out solutions are introduced continuously under pressure or alternately the effluent and/or the saline and salting out solutions or continuously the effluent and/or the saline and by portioning salting out solutions or alternately the effluent and~or the saline followed by salting out solutions, with that the effluent and/or the saline contains cations or anions whereas the salting out solutions contain anions or cations which in the effect of the reaction form rifts sealing suspensions of crystals identical and/or isostructural with the rock mass salts.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of sealing a crack or capillary rift in a rock mass of a saline excavation comprising supplying to the crack or rift a solution of a salt isostructural with the salt forming the rock mass and at the same time or subsequently adding a salting out medium which causes the isostructural salt to crystallize on the surface of the wall of the crack or rift thereby sealing the crack or rift, wherein the salting out medium is an aqueous solution of a salting out salt or an organic solvent, and the temperature of the isostructural salt solution and the salting out medium is substantially the same as the temperature of the rock mass.
2. The method of claim 1 wherein the saline excavation is a rock salt or potassium salt mine.
3. The method of claim 1, wherein the isostructural salt is potassium or sodium chloride and the salting out medium is an aqueous solution of calcium or magnesium chloride or an organic solvent selected from the group consisting of acetone and methanol.
4. The method of claim 1, 2 or 3 wherein the salting out medium is added continuously with the isostructural salt solution.
5. The method of claim 1, 2 or 3 wherein the isostructural salt solution is added continuously and the salting out medium is added in batches.
6. The method of claim 1, 2 or 3 wherein the isostructural salt solution and the salting out medium are added alternately.
7. The method of claim 1, 2 or 3 wherein the isostructural salt solution is effluent or modified effluent already present in the rock mass.
8. The method of claim 1, 2 or 3 wherein the isostructural salt solution and the salting out medium are added under pressure.
9. The method of claim 1, 2 or 3 wherein the isostructural salt solution further contains cations or anions and the salting out medium further contains anions or cations which ions when together in solution precipitate as crystals which are not isostructural with the salt forming the rock mass and form a sediment which assists in sealing the cracks or rifts.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PLP-214184 | 1979-03-15 | ||
| PL21418479A PL126464B1 (en) | 1979-03-15 | 1979-03-15 | Method of sealing salt mine workings |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1138212A true CA1138212A (en) | 1982-12-28 |
Family
ID=19995142
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000340032A Expired CA1138212A (en) | 1979-03-15 | 1979-11-16 | Method of sealing salina excavations |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1138212A (en) |
| PL (1) | PL126464B1 (en) |
-
1979
- 1979-03-15 PL PL21418479A patent/PL126464B1/en unknown
- 1979-11-16 CA CA000340032A patent/CA1138212A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| PL126464B1 (en) | 1983-08-31 |
| PL214184A1 (en) | 1980-11-03 |
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