Överkörd Natur

Tibet, HongYuan wetland

Sven Björk

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The Hongyuan wetland research project, Tibet

The project financed by the Swedish Agency for International Technical and Economic Co-operation
Berdningen för Internationellt Tekniskt-ekonomiskt Samarbete BITS

Summary from Björk.S. 1993.

Swedish Team

Sven Björk, Pål Börjesson (recirculation of peat ash), Gunnar Digerfeldt (quaternary geology), Stina-Mina Ehn (availability and consumption of vegetables), Börje Ekstam (ecological botany), Per Johansson/ Bo Verner (environment engineering, energy demand and production technology), Kai-Sang Phuiling (interpreter English-Scandinavian-Tibetan dialects), Göran Larsson (horticultural peat quality and use), Jörgen Pedersen (wetland vehicles and equipment), Magnus Thelaus (quaternary geology), Sven Westergård /Per-Åke Andersson (peat mining machinery).
The project was documented by Dr. Barbro Soller, the Swedish Television, who produced the film "Yakarnas land/The Land of the Yaks".

Location of Sichuan province in China and the Aba Zang and Qiang autonomous prefecture   Aba Zang and Qiang Nationalities Autonomous Prefecture in Sichuan Province

1 Location of Sichuan province in China and the Aba Zang and Qiang autonomus prefecture, including the Hongvuan-Ruoergai high plateau, in Sichuan.
2 The Aba Zang (Tibetan) and Qiang Nationalities Autonomous Prefecture and its location in Sichuan Province.

Introduction

The relations between man and nature in the Tibetan grassland landscape of the high plateau has for centuries been characterized by having successfully developed a delicate balance between human demands and the prevailing conditions, thus causing no damage to the environment. Recently the administrative Aba Zang (Tibetan) and Qiang Nationalities' Autonomous Prefecture was established in the area originally named Amdo Ngaba. After the invasion in 1950-51 an immigration of Chinese has taken place. New types of activities have been introduced, with a demand for energy as a consequence.

In the search for local energy resources, Chinese geologists identified peat as a potentially suitable fuel for energy production in the Tibetan Kachudo region, now in the Hongyuan County of the Aba Prefecture. Peat is used by the Chinese population for heating and cooking and is supposed to be a future fuel of the Hongyuan yak milk powder factory. However, mining of peat cannot be looked upon and treated as an isolated undertaking, but must be dealt with as an integrated part in the total ecological and socio - economical unit of the Hongyuan region. This holistic approach is necessary because all forms of human activity must be achieved in such a way that environmental degradation is prevented and sustainable living conditions secured. In the extremely sensitive natural environment of the high plateau, clumsy technology and primitive exploitation would rapidly result in the destruction of a long-established pattern of life and in the creation of an environmental and cultural slum.

The joint cooperative project between the Sichuan Institute of Natural Resources (SINR), Chengdu, and the University of Lund, Sweden, regarding an Ecological and Technichal Feasibility Study of Peat Mining in Hongyuan is distinguished by its holistic view of the optimal and sustainable use and management of environmental resources. With the common aim to give the Hongyuan peat project a modern, eco-technical design as a demonstration project, much information and experience has been gained and exchanged.
On behalf of the Swedish team it is a great pleasure to extend our warmest thanks for splendid cooperation to the Chinese and Tibetan authorities for their support of the project and especially to our colleagues of the SINR team, headed by Director Chen Linbin and Shang Chenglin, M.Eng.Sc. We also express our sincere thanks to the Swedish Agency for International Technical and Economic Co-operation (BITS) for financing the Swedish participation in the project.

The connections between the Sichhuan plain and the Hong Yuan Ruo Erg Gai high plateau

Road construction up to Hong gyuan Rou Er gai
Road constructed in narrow river vallies 1989 and 1992
Mountains surrounding the high plateau. A pass at 4200 m is teh highest point on the ordinary road from Chengu to Hong Yuan 1990

Aba Zang and Qiang Nationalities Autonomous Prefecture

The Aba Zang (Tibetan) and Qiang Nationalities Autonomous Prefecture and its location in Sichuan Province.

On the Hongyuan-Ruoergai high plateau large areas are covered by peat in the form of soligenous and topogenous mires. Before any decision was taken concerning the industrial extraction of peat, detailed investigations had to be carried out concerning the quality of the peat, the quantities available and ecologically suitable mining and processing technology. It is stressed that a close collaboration between ecology and technology is necessary in order to achieve the required integrated solution for successful peat extraction and environmental protection.

The present summary is based on cooperative field studies undertaken from early summer to autumn of the period October 1989 - August 1992, on discussions with local authorities and team members, and on basic information contained in technical reports by the participants in the Swedish research team. The laboratory analyses were completed in December 1992.

The landscape of the high plateau

Grazing yaks close to the town Hong Yuan at River Baihe, a tributary to the Hwang Ho, the Yellow River 1987
Soligenous peat mires. The Tibetan tents set up on minerogenic ground 1987
Reconnoitring soligenous mires 1990
Drained wetland (topogenous peat mire) at Waqie, north of Hong Yuan 1987,1991 and 1991

Climatic conditions

The fundamental fact that mining and open-air handling of peat is totally dependent on weather conditions must always be kept in mind. Although the local climate at Hongyuan is characterized by sudden changes, occurring at irregular intervals during summer, making mining impossible for shorter periods, the weather conditions are in general favorable for the mining, drying and freezing of peat.

Peat resources, preliminary estimations and present use

The Chinese survey of peat deposits on the Hongyuan-Ruoergai plateau resulted in an estimation of the peat resources at 1.9 thousand million tons air-dried peat. The analyses included in the survey indicate that the ash content usually varies from 25 to 50 %, but may in places reach values as high as 50 to 70 %. In the preliminary feasibility study (Björk & Digerfeldt, 1987) it was concluded that a considerable part - probably the major portion - of the peat must be considered unsuitable or only marginally suitable as fuel for energy production.

According to local information, peat has not been used as fuel by nomadizing Tibetans. However, Chinese people moving in after the high plateau was opened by road to the Sichuan plain, started to use peat as fuel for cooking and heating. Peat has also been used as fuel in a brick factory and, also experimentally after being mixed with coal, in the Hongyuan milk powder factory. This cutting of peat, which was not carried out according to any plan, has resulted in serious environmental degradation. The unplanned peat extraction was stopped by the local authorities in 1991, but cutting had to be allowed again for a period to meet the fuel demands of the citizens of Hongyuan Town. Due to relatively low furnace temperature and no demand for energy effective burning, no serious problems have been caused by the high ash content when peat has been used in the brick factory and for domestic heating and cooking.

Uncontrolled mining of soligenious peat mires
close to Hong Yuan town.

1987
1989
1990
1991

Objectives, methods and guidelines of activities within the feasibility study

The Chinese - Swedish joint project has aimed at the application of a modern management programme for the utilization of peat resources without disturbing the balance between nature and man. It has been stressed that a holistic view must be taken on the ecological and socio-economical character of the Hongyuan region and that peat mining should not be allowed to be looked upon as an isolated undertaking. On the contrary, it has to be well adjusted to and integrated in the way of life developed under the specific conditions imposed by the natural environment of the region.

The peat deposits in the vicinity of Hongyuan Town which are considered most suitable for mining have been the subject of quantitative and qualitative investigations. Technical methods for ecologically correct peat extraction as well as for the production of both fuel and horticultural peat have been developed and demonstrated. The peat sods produced are used for domestic cooking and heating and mixtures of horticultural peat have been used as a growth medium in the experimental project greenhouse. The importance of the inhabitants to have access to locally produced vegetables is established.

It is very obvious that the present "development" of Hongyuan Town and its environment implies a general degradation of the region, strikingly in contrast to the admirable freshness of the original Tibetan landscape. In accordance with the holistic approach of the joint project, problems connected with water supply, sewage, waste water and solid waste have also been treated. The relations between the indigenous peoples and immigrants have for very obvious reasons attracted great interest.


Results and recommendations

Peat deposits around Hong Gyuan in Tibet

Peat Alocation Near Hong Yoan Town
Map of peat depoits (enclosed areas, some of them with Roman figures) around the town of Hong Yuan

Peat quantity and quality

Among the peat mires considered most attractive for mining in the vicinity of Hongyuan Town, only two, the soligenous Hongyuan I and II, have turned out to be suitable for industrial extraction. Together they contain about 1.7 million m3 of wet peat, with an ash content of 20-30% and a net calorific value of 6.6 MJ/kg. The peat does not contain any elements that would make it unsuitable for horticultural purposes.

As a representative of topogenous mires, the Waqie basin has been investigated. Of this 100 km2 of wetland about 10 km2 have been studied in detail. While the soligenous Hongyuan I and II have a homogenous stratigraphy, the deposits in Waqie are irregular with layers of silt and clay and strata containing peat mixed with minerogenic material. The ash content of these large quantities is, therefore, high and the extraction of peat suitable as fuel is difficult. No elements that would make the peat unsuitable for horticultural use have been found here either.

In all the mires investigated the highest ash content has been recorded in the upper and lower parts of the peat column as well as in the marginal zones. Because the wetlands have been drained, subsidence is taking place, a process resulting in a successive increase in the ash content of the upper peat layer.


Peat prospecting combined with ecological investigation. Obtaining data för the Environmental Impact Assessment, EIA (Swedish Miljökonsekvensbeskrivinning MKB).

Peat prospecting. Obtaining of transect investigation through soligenious mires. Stratigrafic investigations and sampling for age determination, chemical analysis and peat classification. Foto 1992, 1990 and 1992
Field investigations of flora,  vegetation seedproduction and predation 1990
Studies of recolonization of mire vegetation in a test area restored after destructive uncontrolled mining 1990
Investigation on germinability of seed of native plantpopulations 1990

Wetland flora and vegetation

The flora of the mires is diverse and the vegetation productive. About 200 species were collected on or close to the mires being studied. The vegetation is characterized by a long growing season and rapid regrowth after the winter period and grazing. The plant cover has an extremely well-developed rhizome and root system, resistant to intensive trampling and with a capacity to prevent erosion. In Hongyuan II the standing crop amounted to ca 3,000 kg dry matter per hectare in July. The great number of species responsible for the high standing crop guarantees an even production, sustainable under different kinds of climatic stress and pest attacks, and at the same time it constitutes the naturally varied feed for grazing cattle throughout the year.

Diaspore bank and recolonization

The maximum seed bank density, approximately 12,000 individuals per square meter (0-15 cm depth) was found in a fenced area of Hongyuan II, the second season after grazing animals had been excluded. The previous year the density in the top 5 cm of peat was considerably lower, suggesting that grazing may reduce the seed production and the density of soil seed banks. A seed predation experiment showed that a substantial amount (>80 %) of large, freshly produced seeds may be lost to predators. Vegetative propagation (development of buds on rhizome fragments and other perennial organs) was probably more important than seed germination for the establishment of the graminoid species.

When mining soligenous mires the extraction has to stop about one meter above the minerogenic soil, i.e. just above or at the level at which the ash content starts to increase. The peaty layer remaining after mining should immediately be seeded with diaspore bank material shaved off from the natural vegetation cover uphill from the mining strips. Recolonization with native diaspore material guarantees the development of a resistant and productive vegetation. The introduction in such areas of foreign species, ecologically not adapted to the high plateau, is out of the question.

Erosion and sediment transport caused by uncontrolled mining of soligenous peat.

Erosion downhill the mire 1989
Erosion downhill the mire 1990
Eroded material transported by water to River Baihe, a tributary of Yellow River

Mining, transport, drying and processing of peat

In soligenous mires mining should start from the lowest portion and proceed uphill. However, before any extraction starts, surface water flowing downhill must be diverted from the mining area along shallow grooves conducting the water within the unmined marginal zones.

By means of the machinery for mining and for the production of fuel peat, donated by Sweden to the Hongyuan project, the mining procedure has been demonstrated at Hongyuan II. From the strips intended for stepwise, downward mining, the top 5-10 cm layer with native vegetation should be shaved off and later used for the seeding off finally mined-out strips. It is of the utmost importance that the surface of the strip to be mined is carefully leveled before mining starts.

Pretreatment of soligenous mires before peat miining

Construction of shallow grooves for the deviation of surface water from mining areas. The screw-shaver also used for obtaining donor dispore material when making peat stripes ready for mining  1990
A water deviation groove immediately after construction 1990
The same groove one year late. The bottom firmed up by root systems and resistant to erotion  1991

For the transport of extracted peat a flexible, light-weight, narrow-gauge railway system should be used, allowing an uninterrupted flow of peat from the mining site to the drying field. The mining equipment granted from Sweden has such a capacity that all demands for peat within the Hongyuan region could be satisfied, provided an efficient transport system is made available.

Swedish peat mining equipment 1992
Levelled stripof soliggenous mire ready for mining  1992
Peat mining and loading of extracted peat The rails and wagons inappropriate and too small for efficient transport of extracted peat 1992
Provincial arrangement for transport and unloading of extracted peat 1992

The peat which is intended to be used as fuel should be transported straight to the Swedish equipment for producing peat sods. In order to avoid expensive and time-consuming transport of wet peat containing 80-90 % water, the machinery producing the peat sods should be installed on the drying field, located on minerogenic soil close to the mining site, for immediate processing of fuel peat. The peat sods produced have to be dispersed on the drying field and, after drying, are ready for use as fuel. The air-dried peat sods should be stored under shelter.

Production of     peat sods 1992.

Extracted peat intended for horticultural purposes should be directly spread out on the drying field. Most qualities of horticultural mixtures contain frozen peat, sifted before any addition of nutrients, selected fractions of minerogenic matter etc.

Mining topogenous mires poses problems quite different from those of mining soligenous deposits. With the drained Waqie basin as an example, further drainage should not be undertaken, because this would result in a further increase in the ash content of the peat and a general drying out of the landscape. Apparently drainage projects have been executed without any prognostication concerning long-term local and downstream effects. Extraction of peat in topogenous mires should be performed without the groundwater level being lowered, if necessary modified by longer mining screws. Before extracting the peat along a groove as broad as the screws (= 60 cm), the top layer, including the living vegetation is removed by means of the screws. Thus, both the mining machine and the narrow-gauge railway transport system should be working on existing tough root felt capable of supporting the weight of this equipment. The extracted peat should be transported to drying fields on minerogenic soil. This model for mining results in the creation of shallow waters which will be colonized partly by vegetation and under all circumstances will be attractive for waterfowl and fish, thereby to some extent constituting a compensation for the great environmental losses caused by draining the wetlands of the high plateau.

Feul peat

Until 1992 unpressed peat was used as fuel by the inhabitants in Hongyuan Town and by the brick factory. In the milk powder factory a mixture of coal and 30-45 % peat was tested in 1987. In this case the air-dried peat-blocks were manually broken up before being mixed with coal and burnt. After the Swedish machinery for production of peat sods had been delivered, this type of fuel has been available and is appreciated by the Hongyuan citizens for heating and cooking. The low temperatures in household stoves burn the peat to an ash powder. Large-scale burning at high temperatures may result in the formation of glass and to boiler damage. Because the production of peat sods did not start until the summer of 1992, no full-scale tests with sods extruded from Hongyuan peat as fuel for industrial boilers have been carried out. It is, therefore, still an open question whether peat sods with such a high ash content can be used as fuel in the milk powder factory. Tests with fuel consisting of only peat sods, as well as different mixtures of coal and peat sods, should be made before any decision is taken concerning the type and size of boiler to be installed in the milk powder factory.

Environmental pollution

The Hong Yuan yak milk powder factory 1989
A  tributary to the Baihe River dowstream the milk powder factory polluted by sewage and industrial waste water 1990
The confluence of a clean stream of heavily polluted water from the milk powder factory. Note the large stands of flowering Ranunculus in the clear stream 1990

Peat ash of the type obtained from household stoves has been investigated with respect to its utility as fertilizer. The ash is poor in nitrogen available to plants, but contains important macro-nutrients such as calcium, magnesium, potassium and phosphorus in addition to essential micro-nutrients. No dangerous concentrations of harmful heavy metals are found in Hongyuan peat ash. The liming effect and the content of valuable nutrients makes the pure peat ash a valuable fertilizer. It has to be emphasized, however, that peat ash should not be mixed with coal ash containing elements harmful to plants.

Horticultural peat

The physical as well as chemical properties of the Hongyuan and Waqie peat makes it excellent for horticultural purposes. In this context neither the high ash content in general, nor the layers of silt and clay as in the Waqie basin cause any problem.

An extensive test programme has been carried out to demonstrate the vast possibilities for the use of peat as a growth medium for the production of plants, in particular vegetables, which are a commodity in short and irregular supply in the Hogyuan region. Detailed recommendations have been given concerning greenhouse design, horticultural soil mixtures, selection of plant types, and the management of cultures in greenhouses. At this very early stage of greenhouse use on the high plateau, with a new growth medium etc., an immediate start of commercial production would certainly result in big failures and give this very promising activity a bad reputation. The data from the project test greenhouse will, however, successively give a firm basis of reliable results and experience for future prosperous commercial production. It is also recommended that the people managing the experimental greenhouse should be given training within relevant sectors of plant cultivation to be able to act thereafter as skilled consultants to greenhouse plant producers on the high plateau.

In the feasibility study special attention has been focused on the decisive importance of controlling the temperature, light and water conditions. Also, special consideration has been given to the question of compound fertilizers.

Hongyuan is situated at latitude ca 33o north, i.e. at the same latitude as southernmost California, Casablanca, Tripoli, Haifa and Baghdad. In combination with the location on the high plateau, about 3,500 m a.s.l., this gives rise to stress problems, caused by light and temperature, in plants grown in ordinary greenhouses. However, utilization of the new design for greenhouses with roofs of Linear Fresnel Lenses (LFL), makes it possible not only to avoid the negative effects of the intensive isolation and adverse temperature regime, but also to make use of the very specific light and temperature conditions of the high plateau so as to optimize the greenhouse cultivation of plants. By means of this recently developed type of construction, the ordinary greenhouse is transformed into a hothouse which, in the case of Hongyuan, is independent of heat from the milk powder factory which functions only seasonally. In spring and autumn, when insolation is intensive in the daytime, but low night temperatures prevent ordinary greenhouse cultivation at Hongyuan, access to LFL roofs means that excess direct radiation is absorbed and this accumulated heat is utilized for warmig the house and its growth beds. Furthermore, on bright summer days, when the very high temperature in the ordinary greenhouse damages the plants, a great part of the direct solar radiation is converted into heat collected by the tube absorbers of the LFL roof and removed by the pipe-and-pump system for use inside or outside the greenhouse.

Investigations of peat for horticultural purposes

Laboratory growth tests with peat of different origin and pretreated in diferent ways 1990
The project greenhouse at Hong Yuan 1992

In summary, the LFL system is extremely well suited for use under the very specific conditions prevailing at Hongyuan on the high plateau. This system makes it possible to prolong the growing season considerably and to overcome the present problems concerning light and temperature in the ordinary greenhouse. The combination of LFL-greenhouses and an unlimited supply of horticultural peat makes the future production on the high plateau of vegetables and other plants very promising.

In this connection the existence in Hongyuan of the Grassland Reserch Institute is also of importance. Within the framework of the feasibility study staff members from this institute have demonstrated great interest and skill in the development of the methodology of greenhouse horticulture.

Restoration of areas destroyed by unplanned mining

The ecologically degraded portions of Hongyuan I should be restored as soon as possible. After levelling, this part should be seeded with native plant material in order to stop erosion and to re-create the highly diverse vegetation most suitable for grazig yaks and resistant to trampling. It might be tempting to grow monocultures of lowland plants for hay. This would, however, be a complete failure and cause further degradation.

Water, waste water and solid waste

In Hongyuan Town the water supply comes from several shallow (2-5 m) and three deeper (10-15 m) wells. The water has high concentrations of iron and, at least periodically, the high concentrations of coliform bacteria indicate pollution of the groundwater.

The town inhabitants have access to one latrine pit per ca. 40 persons. Neither sewage nor any other waste water is treated. Solid waste is deposited on several sites within and around the town, part of it along the banks of the Long Rang Ke stream.

The milieu of Hongyuan Town gives a general impression of dirtiness, and this dirt produces pollution of the groundwater. An urgent task is to secure a supply of high-quality water for both the food industries and the citizens and to bring about a general upgrading of the deteriorated environmental conditions. This would, of course, include a satisfactory treatment of sewage and waste water in order to prevent the pollution of watercourses downstream from the town. These measures should be given higher priority than any other plans such as increased industrialization, or increased immigration, etc.

Energy demand and production technology, upgrading of present systems

In Hongyuan Town the two main fuel consumers demanding fuel peat are the milk powder factory, and the town citizens, who, so far, have also used wood as fuel. In the factory ca 96 % of the total energy required is used in the form of steam, the rest as electricity.
Cf. the List of references.
Johansson, P. & Verner, B. 1993. The Hongyuan wetland research project. Environment engineering, energy demand and production technology. - Department of water and environmental engineering. Lund institute of technology, University of Lund.

Problems concerning fuel peat

One of the objectives of the feasibility study was to give advice on a programme of energy production by a 1 MW experimental thermal power station run on peat in the Hongyuan milk powder factory. However, the primary objective of the study, i.e. the investigation of the quality and quantity of the peat resources in the Hogyuan area, has shown that a plan for large-scale use of peat as fuel faces two main problems, viz. firstly, the high ash content, and secondly, the fairly limited volumes of industrially extractable peat with reasonably acceptable ash content.

The ash content of the Hongyuan peat is much higher than that of peat used as fuel, for instance, in Europe. Because manufacturers lack experience in the design of boilers needed for burning peat of the specific Hongyuan type, and because high ash content is a serious problem (boiler destruction) in general in connection with large-scale burning, the difficult task of providing the correct advice on boiler type for a steamturbine-generator set (smallest standard available = 4 MW), an advice which must be well-founded and given extremely thorough consideration, has not yet been tackled.
The general procedure before a decision is made concerning boiler type includes test series of burning realistic volumes of the peat in question in order to elucidate the characteristics of the boiler problems successively appearing. Such a project could not be carried out within the framework of this feasibility study.

The usefulness of Hongyuan Peat

As explained above, the problem concerning the large-scale and long-term use of Hongyuan peat as fuel for boilers still remains unsolved and careful tests must be made in order to provide the solution. However, data and the experiences gained from the feasibility study leave no room for doubt that the peat is suitable and attractive as fuel for domestic use and excellent for the production of horticultural soil mixtures. It has, furthermore, been shown that greenhouse production on the high plateau of vegetables and other plants would be very successful. Methods for mining have been elaborated and demonstrated and equipment covering all present needs for both extraction and production of fuel and horticultural peat has been made available. Provided the ecological directions are followed - as stated in the project agreement - peat mining of already drained mires is recommended. The production of domestic fuel and horticultural peat would then be combined with a badly needed restoration of degraded wetlands on the high plateau. Such a combination would be of local benefit and internationally appreciated, assuming that all activities are carried out in mutual understanding with the autonomous Tibetans.


Further reading

Björk, S. 1993. The Hongyuan wetland research project. An ecological and technical feasibility study of peat mining in Hongyuan, Sichuan, China. - Department of Limnology, University of Lund, Sweden, and Sichuan Institute of Natural Resources, Chengdu, China.
Björk.S. & Digerfeldt, G. 1987. The Hongyuan peat project. Report from a study visit. - Departments of Limnology and Quaternary Geology, University of Lund.
Björk, S. & Thelaus, M. 1996. Torvmarker i Kachudo, Tibet. Tillämpad våtmarksforskning. - Ymer. Svenska sällskapet för antropologi och geografi. ISSN 0044-0477.
Börjesson, P. 1992. Peat ash in Hongyuan. A study of possibilities to recirculate ash from peat burning. - Swedish University of Agricultural Sciences. International Rural Development Centre. ISSN 1100-8679.
Ehn, S-M. 1992. Vegetables in Hongyuan. A study of availability and consumption of vegetables in selected urban and Tibetan households. - Swedish University of Agricultural Sciences. International Rural Development Centre. ISSN 1100-8679.
Ekstam, B. 1993. Flora, structure and regeneration of wetland vegetation in Hongyuan, Sichuan, China. - Department of Limnology, University of Lund, Sweden, and Sichuan Institute of Natural Resources, Chengdu, China. ISSN 1100-6366.
Johansson, P. & Verner, B. 1993. The Hongyuan wetland research project. Environment engineering, energy demand and production technology. - Lund Institute of technology, University of Lund.
Thelaus, M. 1992. Some characteristics of the mire development in Hongyuan County, Eastern Tibetan Plateau. - International Peat Congress.


The Chines Swdeish team active in the Hong Gyuan Ruo Er Gai high plateau

The Chinese-Swedish team active in the Hongyuan-Rouergai high plateau. Foto 1989 in front of the Chengdu Institute of National Resourses.

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