How difficult was Muraviev's amassing of troops for the forcing of the Treaty of Aigun, and what effects on development did it have?

The following is taken from the book (in Russian)

Natalia Mathanova, "Governors-general of Eastern Siberia in mid-19th century", Novosibirsk, 1998. (This is Mathanova's doctoral dissertation.)

Muraviev arrived to Irkutsk as a governor-general of the entire Eastern Siberia in 1849. While there is some disagreement regarding his goals (see pp. 117-118 of the book), one far-reaching objective (from the very beginning) was the (re)conquest of the Amur region:

"возвраще­ние России Амурского края стало основной целью дея­тельности Муравьева с самого ее начала."

While by 1849 Russian far East already had some number of cossacks settled there,

Проект Муравьева, осуществленный в 1851 г., вносил кардинальные изменения. Если его предшественники предлагали из­менить количество казаков в пределах одной — двух тысяч, то по предложению Муравьева их штатная чис­ленность была доведена почти до 16 тыс. чел., а после включения в состав казаков нерчинских горнозаводских крестьян к ним прибавилось еще около 30 тыс. Реально к 1857 г. он располагал на границе примерно 23 тыс. чел. Если в 1830—1840-е гг. речь шла о создании бригады, передаче казаков в военное ведомство, то Муравьевым было создано войско, подобно Донскому или Оренбург­скому. Но главное — Забайкальское казачье войско по­ лучило совершенно новое назначение, связанное с пла­нами Муравьева на Амуре.

Muraviov's project, carried out from 1851 onward, introduced dramatic changes. If his predecessors proposed to change the number of Cossacks within one - two thousand, Muraviov's proposal was to increase their numbers to almost 16 thousand people, and after the inclusion of the Nerchinsk mining and refinery peasants in the ranks of Cossacks, about 30 thousand more were added to them. 1857 Muraviev had about 23 thousand cossack troops at his disposal near the border. If earlier (1830-1840s) the question was about creating a cossack brigade, transferring the Cossacks to the military department, then the Muraviov created a cossack army, similar to ones in Don or Orenburg regions. But the main thing is that the Transbaikal Cossack army had a completely new task associated with Muraviov's plans of reconquest of the Amur region.

(It might be more appropriate to call this "conquest" rather "reconquest," but this is a minor grumble.)

Here is how colonists and cossack troops were brought to the region: While most large Siberian rivers flow South-to-North, the Amur river (and its triburary, Shilka river) mostly flows West-to-East, so it can be used for transport.

Pages 169-171:

До заключения в 1858 г. Айгунского трактата было осуществлено четыре сплава по Амуру (сам договор под­ писан во время пятого), основано несколько военных постов по берегу реки, в 1855 г. переселились на Амур первые 50 крестьянских семей из Иркутской губернии и Забайкальской области, в 1857 г. началось переселение туда казаков из Забайкальского войска. Таким образом, колонизация фактически началась до заключения офи­циального договора.

Prior to the conclusion of the Aigun treaty in 1858, Muraviev organized four rafting expeditions along Amur river (the treaty itself was signed during the fifth), several military posts were founded along the river bank, in 1855 the first 50 peasant families from the Irkutsk province and the Trans-Baikal region moved to the Amur. In 1857, the Cossacks from the Trans-Baikal army began to move there. Thus, colonization actually began before the conclusion of a formal treaty.

In other words, Muraviev was creating "facts on the ground," which is why by 1858 he had all these troops along Amur river at his disposal. Simultaneously with cossacks, more than a thousand of regular army troops (including artillery) were carried down the river in as well.

One more name should be mentioned in connection to all this, Admiral Gennady Nevelskoy, responsible the naval exploration of the region (1849—1855). See

Виталий Тренев, Путь к океану, Москва, 1958.

and

П.И.Кабанов, "Амурский Вопрос," Благовещенск, 1959.

for further details. [Usual caveats apply: Soviet-period sources should be treated with extra care and double/triple checked.]