Table 5.2: Hydroseeding specifications for establishing grass/legume cover in temperate climates

Sl. No.	Material	Rate of application
1.	Mixture (appropriate) of grass-seeds (including nursecrop in exposed situations)	70 kg/ha
2.	Wild white clover or other legume (innoculated and pre-germinated if necessary)	10 kg/ha
3.	Mulch: woodfibre, chopped straw or glasswool	1-2 t/ha
4.	Stablizer: woodfibre, alginate PVA or latex (if likelihood of severe erosion)	Depending on stablizer
5.	Fertilizer: complete 15:15:15 (slow release N-fertilizer value if legume is not included)	200 kg/ha followed by 300 kg/ha after 8 weeks
.	or	.
.	Dry organic matter	500 kg/ha
6.	Lime (if pH requires this and may have to be spread separately)	0-500 kg/ha

Source: Bradshaw and. Chadwick, 1980

5.5 Soil management
If the mineral to mine is deep-seated, covered by OB and topsoil, preservation of this topsoil is very important. It is to be collected separately by scraping the top 10-150 cm layer (depending upon the soil profile) and stored properly to preserve its biolife and physical properties. In Indian condition (tropical climate) such scraped soil prove to be vulnerable to erosion, and if lost, create serious ecological damage by forming siltation on surrounding land and water and also creating loss of topsoil, a worthy natural resource; as nature takes several years to form 1 cm of topsoil.

Hence it will not be justified to loose the topsoil by getting mixed with subsoil or OB. Thus a calendar programme has been chalked out to reuse topsoil for its (most rapid use) on back-filled quarries even without requiring preservation through long time and has been named as "continuous and concurrent reclamation mining" (Ghosh & Ghosh, 1990a) as detailed below.

The model postulated here for reclamation in OC mining areas uses the "continuous reclamation mining method" outlined in Coates (1981, pp.600) as the base. Originally a somewhat similar method was used by EXXON Mining Corporation for surface mining without leaving significant scars on the land. A significant improvement in the proposed model over the earlier methods is the scope for special care to preserve and utilise the topsoil and subsoil separately and effectively. The method is good mainly for sedimentary deposits only.

As a first step, the total area for OC mining should be divided into more or less uniform plots of smaller size so that mining in each plot can be finished in 6 months. The exact size of the plot should depend on the mechanisation and labour force available. Actual operation should start with corner plot, i.e. plot 1, which should be excavated first only to take out and dump the topsoil and subsoil separately in the fringe area of this plot. Preservation of these dumps should be such that these are not washed away within one year. For this, any available natural depression (not holding an usable water source) should be preferred as dumping ground. Suitable embankments may be constructed to prevent rain washing. A comparatively easy method, involving minimum expenses for preservation of sub-soil is to put on the dump the cut-out twings and leafy parts of the plants and other types of greeneries to form a mulch. In fact site preparation would require cutting out some amount of greeneries which can be used for such purposes. Grasses with their roots and 6? of soil (in the form of soddings) can be used to cover the topsoil dump to obtain a special care for preserving biolife of the soil. The grasses will survive very easily and will form a temporary cover on the soil heaps and protect it from being washed away by rain waters. The leaves will protect the soil at their base until they are dried, rotten and decomposed. The roots of grass and cut-out plants will act as soil binder until these are decomposed. After decomposition these will add nutrients to the underlying soil. Even some of the roots may grow to give rise to some natural vegetation and protect soil from erosion (Haigh, 1976). Thus according to this plan, the soil along with its fertility will be preserved for one year at a minimal cost in terms of labour only.

The next step would involve excavation of OB from plot 1. The OB is to be dumped separately at a properly selected site and preserved by planting rapidly growing grass and shrubs on the dump so that the dump is preserved for a longer time. Studies about slopes of lands disturbed by surface mines suggest that the slopes covered by a dense seeded turf have about a third of soil loss than the unvegetated parts (Haigh, 1976).

Then comes the actual exploitation of the mineral and its transportation. Towards the last phase of extraction of mineral from plot 1, site preparation should begin in the neighbouring plot2. This starts with removal of vegetation and its temporary dumping over the topsoil and sub-soil heaps from plot 1. This is followed by removal of topsoil and sub-soil from plot 2, to be covered immediately by the freshly heaped vegetation mulches over the topsoil and subsoil heap from plot 1. By this time mining operation should be completed in plot 1.

The removal of OB from plot 2 starts, which should be put in the exploited pit of plot 1. Then as the excavation starts in plot 2, another group of labour should put back first the sub-soil and then the topsoil dump of plot 1, along with the decomposed plant tissues in the filled in (by OB) quarry of plot 1.

Every stage would require mechanical compaction. Two groups of labours in necessary strength should be deployed in a calculated manner, so that this cycle of four stages is completed within one year, before the topsoil and sub-soil looses its nutrients and fertility and hence capacity to grow fresh vegetation.

Repetition of this sequential plan in successively adjacent plots, one after another, should be done to cover the entire area. Finally, the OB dump of plot 1 should be used to fillup the quarry in the last plot. Hence it was mentioned that due care should be taken to select the dumping site for OB from plot 1, and its preservation. An operation plan for this model is presented in Fig. 5.4.